In primary mental disorders cholesterol deficiency purchase genuine atorlip-20, no specific and direct causative physiological mechanisms associated with a medical condition can be demonstrated hdl vs ldl cholesterol in eggs effective 20 mg atorlip-20. Illness anxiety disorder is characterized by a preoccupation with having or acquiring a serious illness cholesterol ratio 2.0 best buy atorlip-20. In the case of illness anxiety disorder cholesterol lowering snack foods discount atorlip-20 20mg free shipping, individuals may or may not have diagnosed medical conditions cholesterol belongs to which class of molecules best order for atorlip-20. Other specified obsessive-compulsive and related disorder or unspecified obsessive compulsive and related disorder cholesterol in steamed shrimp buy atorlip-20 20 mg without a prescription. These diagnoses are given if it is unclear whether the obsessive-compulsive and related symptoms are primary cholesterol levels and pregnancy buy cheap atorlip-20 20 mg on-line, substance-induced cholesterol glucose ratio generic 20mg atorlip-20 mastercard, or due to another medical condition. In such cases, the preoccupation with these flaws is clearly excessive and causes significant impairment or distress. Body dysmorphic-like disorder without repetitive behaviors: Presentations that meet body dysmorphic disorder except that the individual has not performed repetitive behaviors or mental acts in response to the appearance concerns. Body-focused repetitive behavior disorder: this is characterized by recurrent body focused repetitive behaviors. These symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning and are not better explained by trichotillomania (hair-pulling disorder), excoriation (skin picking) disorder, stereotypic movement disorder, or nonsuicidal self-injury. Placement of this chapter reflects the close relationship between these diagnoses and disorders in the surrounding chapters on anxiety disorders, obsessive-compulsive and related disorders, and dissociative disorders. In some cases, symptoms can be well understood within an anxiety or fear-based context. Because of these variable expressions of clinical distress following exposure to catastrophic or aversive events, the aforementioned disorders have been grouped under a separate category: trauma and stressor-related disorders. A persistent social and emotional disturbance characterized by at least two of the following: 1. Episodes of unexplained irritability, sadness, or fearfulness that are evident even during nonthreatening interactions with adult caregivers. The child has experienced a pattern of extremes of insufficient care as evidenced by at least one of the following: 1. Social neglect or deprivation in the form of persistent laci< of having basic emotional needs for comfort, stimulation, and affection met by caregiving adults. Diagnostic Features Reactive attachment disorder of infancy or early childhood is characterized by a pattern of markedly disturbed and developmentally inappropriate attachment behaviors, in which a child rarely or minimally turns preferentially to an attachment figure for comfort, support, protection, and nurturance. However, because of limited opportunities during early development, they fail to show the behavioral manifestations of selective attachments. That is, when distressed, they show no consistent effort to obtain comfort, support, nurturance, or protection from caregivers. Thus, the disorder is associated with the absence of expected comfort seeking and response to comforting behaviors. As such, children with reactive attachment disorder show diminished or absent expression of positive emotions during routine interactions with caregivers. A diagnosis of reactive attachment disorder should not be made in children who are developmentally unable to form selective attachments. Other associated features include stereotypies and other signs of severe neglect. The disorder has been found in young children exposed to severe neglect before being placed in foster care or raised in institutions. However, even in populations of severely neglected children, the disorder is uncommon, occurring in less than 10% of such children. Without remediation and recovery through normative caregiving environments, it appears that signs of the disorder may persist, at least for several years. It is unclear whether reactive attachment disorder occurs in older children and, if so, how it differs from its presentation in young children. Because of this, the diagnosis should be made with caution in children older than 5 years. Prognosis appears to depend on the quality of the caregiving environment following serious neglect. Cuiture-Related Diagnostic Issues Similar attachment behaviors have been described in young children in many different cultures around the world. However, caution should be exercised in making the diagnosis of reactive attachment disorder in cultures in which attachment has not been studied. Aberrant social behaviors manifest in young children with reactive attachment disorder, but they also are key features of autism spectrum disorder. Specifically, young children with either condition can manifest dampened expression of positive emotions, cognitive and language delays, and impairments in social reciprocity. These two disorders can be distinguished based on differential histories of neglect and on the presence of restricted interests or ritualized behaviors, specific deficit in social communication, and selective attachment behaviors. Children with autistic spectrum disorder will only rarely have a history of social neglect. The restricted interests and repetitive behaviors characteristic of autism spectrum disorder are not a feature of reactive attachment disorder. These clinical features manifest as excessive adherence to rituals and routines; restricted, fixated interests; and unusual sensory reactions. Children with either disorder also may exhibit a range of intellectual functioning, but only children with autis tic spectrum disorder exhibit selective impairments in social communicative behaviors, such as intentional communication. Finally, children with autistic spectrum disorder regularly show attachment behavior typical for their developmental level. In contrast, children with reactive attachment disorder do so only rarely or inconsistently, if at all. In contrast, children with reactive attachment disorder show lack of preferred attachment despite having attained a developmental age of at least 9 months. Depression in young children is also associated with reductions in positive affect. Medical conditions, such as severe malnutrition, may accompany signs of the disorder. A pattern of behavior in which a child actively approaches and interacts with unfamiliar adults and exhibits at least two of the following: 1. Reduced or absent reticence in approaching and interacting with unfamiliar adults. Overly familiar verbal or physical behavior (that is not consistent with culturally sanctioned and with age-appropriate social boundaries). Diminished or absent checking back with adult caregiver after venturing away, even in unfamiliar settings. The behaviors in Criterion A are not limited to impulsivity (as in attention-deficit/hyper activity disorder) but include socially disinhiblted behavior. Social neglect or deprivation in the form of persistent lack of having basic emotional needs for comfort, stimulation, and affection met by caregiving adults. Specify current severity: Disinhibited social engagement disorder is specified as severe when the child exhibits all symptoms of the disorder, with each symptom manifesting at relatively high levels. Diagnostic Features the essential feature of disinhibited social engagement disorder is a pattern of behavior that involves culturally inappropriate, overly familiar behavior with relative strangers (Criterion A). A diagnosis of disinhibited social engagement disorder should not be made before children are developmentally able to form selective attachments. However, signs of the disorder often persist even after these other signs of neglect are no longer present. Therefore, it is not uncommon for children with the disorder to present with no current signs of neglect. Moreover, the condition can present in children who show no signs of disordered attachment. Nevertheless, the disorder appears to be rare, occurring in a minority of children, even those who have been severely neglected and subsequently placed in foster care or raised in institutions. In such high-risk populations, the condition occurs in only about 20% of children. However, there is no evidence that neglect beginning after age 2 years is associated with manifestations of the disorder. If neglect occurs early and signs of the disorder appear, clinical features of the disorder are moderately stable over time, particularly if conditions of neglect persist. When the disorder persists into middle childhood, clinical features manifest as verbal and physical overfamiliarity as well as inauthentic expression of emotions. Disinhibited social engagement disorder has been described from the second year of life through adolescence. There are some differences in manifestations of the disorder from early childhood through adolescence. At the youngest ages, across many cultures, children show reticence when interacting with strangers. Young children with the disorder fail to show reticence to approach, engage with, and even accompany adults. In preschool children, verbal and social intrusiveness appear most prominent, often accompanied by attention-seeking behavior. Verbal and physical overfamiliarity continue through middle childhood, accompanied by inauthentic expressions of emotion. Relative to healthy adolescents, adolescents with the disorder have more "superficial" peer relationships and more peer conflicts. Serious social neglect is a diagnostic requirement for disinhibited social engagement disorder and is also the only known risk factor for the disorder. However, no clear link with any specific neurobiological factors has been established. The disorder has not been identified in children who experience social neglect only after age 2 years. Prognosis is only modestly associated with quality of the caregiving environment following serious neglect. In many cases, the disorder persists, even in children whose caregiving environment becomes markedly improved. Comorbidity Limited research has examined the issue of disorders comorbid with disinhibited social engagement disorder.
One of the players in the first team must enter the territory of the other team and tag any of its players by touching them cholesterol norms order atorlip-20 20mg without a prescription. Only when s/he fails to hold his/her breath cholesterol medication frequent urination discount atorlip-20 amex, can players from the other team tag him/her before s/he goes back to his/her territory cholesterol in eggs vs beef order genuine atorlip-20. Sound Poetry Sound poetry is usually taken to refer to vocal compositions in which more emphasis is placed on the non-verbal musical aspects of human vocalizations than on the verbal aspects cholesterol medication in powder form order atorlip-20 20 mg line. This form of poetry cholesterol free eggs calories purchase 20mg atorlip-20 free shipping, which frees the word from its semantic dimension cholesterol medication doesn't work purchase atorlip-20 with paypal, is also referred to as abstract poetry cholesterol test india discount atorlip-20 express, phonetic poetry cholesterol in fresh shrimp purchase generic atorlip-20 line, or sound art. Dada, which also influenced painting and theatre, was characterized by irrationality, cynicism, meaninglessness, and negation of conventional laws and tradition. Another sound poem was also performed by Tristan Tzara and Hans Arp at the Cabaret Voltaire in Zurich. Hausmann referred to his work as optophonetic and used different typefaces and font sizes to typographically notate the written expressions and to indicate the sound associated with each utterance (Figure 5). Hausmann, however, was not the first person to create a visual representation for sound poetry. The Italian futurist Filippo Tommaso Marinetti is thought to have preceded him in creating a visual representation of sound poetry called parole in liberta (words in freedom) [McCaffery, 1978]. The earliest and simplest of these are the tape recorded sound poems of Henri Chopin and Francois Dufrene which are discussed in section 2. Ventriloquism Ventriloquism is an artform in which the ventriloquist deceives the viewer by manipulating, projecting, or throwing his/her voice to give the auditory illusion that it is generated from another source. When the source is distant, for example when throwing the voice, it is referred to as distant ventriloquism. The artform is thought to have developed from gastromancy, an ancient Greek divination in which the diviner speaks to the consulter without moving his lips in order to deceive the consulter into thinking that the source of the voice is a spirit possessing the diviner. A puppet is usually used as the false source of the voice while the ventriloquist speaks or makes non-speech noises by keeping the lips and jaw still. This is possible through the substitution of phonemes that involve obvious oral articulation through lip movement by similar sounding phonemes that can be generated by the tongue or at the back of the throat rather than visibly articulated. The perceptual illusion achieved as a result of the interaction between the auditory and visual illusion is referred to as the McGurk effect, which plays an important role in the perception of speech and in lip reading. Ventriloquism also involves the generation of non-speech sounds such as bird, animal, or other natural sounds. Its application in the domain of performance, however, seems to be mostly confined to forms of art such as singing, chanting, poetry, and ventriloquism. Its application in the domain of human-computer interaction seems to be mostly confined to verbal communicative forms of interaction, namely speech recognition. The paralinguistic and performative uses of voice in human computer interaction have not significantly been exploited. Later, I suggest ways of extending the capabilities of the human voice in interactive media and in performance. When accompanying speech, vocal paralanguage can be an integral prosodic constituent of the verbal utterance (in the form of stress, intonation, rhythm and other patterns), it can be separately interposed between verbal utterances, or both. Voice characteristics include timbre, duration, loudness, intensity, pitch, tempo and arguably envelope. Emotive vocalizations include laughing, crying, sighing, cracking, whispering, yelling, moaning, groaning, sneezing, and coughing. Vocal segregates include vocal fillers (such as uh-huh, ooh, um, uh), silent pauses, and other hesitation phenomena. Albert Mehrabian claims that 55 percent of communication is through body language, 38 percent through vocal paralanguage and specifically vocal tonality, and only 7 percent through actual words [Mehrabian, 1981:76]. During a phone call, the voice timbre and pitch, not the verbal content, is what indicates that the speaker is a female or even a particular familiar female. That is why one may still recognize the person talking over the phone even if this person is a friend pretending to be someone else. That is also why one may recognize the voice of a famous singer on the radio even if the song is new and unfamiliar. Thus vocal paralanguage is very important in identifying identity, gender, and even age. Words can thus convey the opposite meaning when intonation and other paralinguistic cues are used. Language alone may not convey non-linguistic information such as gender and age, nor extra-linguistic information such as attitude and emotion. This might actually be one of the main factors that make the improvement of speech recognition systems moderately slow. Quast suggests that there is great potential in adding further non-speech dimensions to speech recognition systems; these dimensions can make recognition more accurate and allow the extraction of more information [2003]. The non-verbal vocalizations which people generate form one of the most immediate modes of expressive affective communication [Beeman, 1998]. Language itself is deficient in conveying affective states to others, and it requires significant enhancements from other dimensions of communication [Beeman, 1998]. Moreover, vocal signals such as pitch, volume, speech rate and intonation can be better than words in communicating interest and attraction towards members of the opposite sex. If a man greets a woman with a deep-toned, low-pitched voice that rises in intonation at the end of the greeting, then this kind of voice may indicate attraction or interest [Fox, 2003]. However, if the greeting is short, high-pitched and monotonous then this could be an indication of lack of interest [Fox, 2003]. Through measuring the stress and activity features of speech, Madan intends that the interest meter can be used for different purposes including advertising and online dating. A falling intonation and a drop in volume at the end of a sentence may indicate that a speaker is done talking and is giving the turn to the conversation partner to speak. Another significant use of the subtleties of voice is during presentations where a monotonous voice may cause boredom in the audience. A loud low-pitched voice combined with various acceleration, deceleration, and pausing techniques may reflect a sense of credibility and keep the audience interested. This system measures voice characteristics during a speech, and rates the persuasiveness of the speaker. Emerging multimedia technologies, however, still have not fully exploited our natural abilities to perceive sound characteristics and to generate paralinguistic or non-speech vocalizations. Vocal Characteristics Voice characteristics are properties of the analog voice signal and are associated with laryngeal anatomy, vocal tract configuration, and the vibration of vocal folds. The main characteristics of voice include frequency, volume, timbre, rhythm, and duration. The frequency of the voice corresponds to the number of times per second the vocal folds come together during phonation [Scherer, 2000]. In other words, pitch can be subjectively perceived by the ear, whereas frequency is measurable; one can change the perceived pitch without changing frequency value [Karpf, 2006: 35]. The frequency levels that the human ear can hear are in the range between 20 20,000 Hz. Mithen suggests that when one is emotionally upset, it is not easy to stop the pitch of his/her own voice from rising [Mithen, 2005]. Experiments conducted by Saffran and Griepentrog have shown that we are all born with perfect pitch but this ability is replaced in many of us by relative pitch as we grow up [Saffran and Griepentrog, 2001]. People who can retain perfect pitch are those who practice music intensely during childhood or musical savants and autistic children whose cognitive impairments impede their language acquisition [ibid]. The volume of the average voice during a conversation is 60 dB, that of quiet speech is around 40 dB, and that of shouting is around 75 dB [Karpf, 2006:41]. Volumes around 120 dB may create a sense of touch or movement and those louder may cause pain [ibid]. There is a distinction between volume and loudness; volume is measurable and it depends on the intensity of sound while loudness is subjectively perceptible and it can be affected by parameters other than intensity, such as the frequency of sound. For this reason, the Phon has been adopted as a unit for measuring perceived loudness [Hartmann, 1998]. Timbre is the quality that distinguishes a particular voice from any other voice of the same pitch and volume. Timbre is determined by the various overtones present in the sound, and their relative strengths. Overtones are the multiple secondary frequencies that exist in combination with the lowest frequency of the waveform. When these overtones are integer multiples of the fundamental frequency, they are called harmonics. When they are fractional multiples of the fundamental frequency, they are called partials. The average tempo of an adult American or British speaker is around 120 to 150 words per minute (wpm) [Karpf, 2006:42]. Like a wide pitch range, a wide durational range can be tied to the expression of affect [Van Leeuwen, 1999]. Many researchers have attempted to find a relationship between voice characteristics and emotions. Klaus Scherer, for instance, attempted to find the relationship between voice characteristics such as pitch, tempo and rhythm and the emotional expressions they convey. He found that a slow low-pitched voice conveys sadness, while a vocal expression that has a fast tempo and large pitch variations conveys happiness [Scherer, 1995:238]. Mehrabian conducted a number of experiments in order to find emotional correlates of the implicit prosodic characteristics of speech as perceived by listeners. Louder voice and faster rate, however, indicate persuasiveness and influence while higher pitch and slower rate indicate submissiveness and passiveness [Mehrabian, 1981: 48, 49]. Monotonous voice, which has no variety in pitch, indicates that the person is less credible and less persuasive [Mehrabian, 1981: 152]. High-pitch level and slow speech rate indicate deceit and untruthfulness [Mehrabian, 1981: 153]. The following table summarizes the paralinguistic information conveyed by various voice characteristics based on studies and experiments undertaken by a number of researchers (Table 1). One key issue that emerges in the table, and which will be pursued later in the context of my own work, is the possible relationship between voice and shyness. Emotive Vocalizations Expressing emotions is a vital component of our daily human interactions. A significant part of this emotional communication occurs non-verbally through the generation of emotive vocalizations as laughter, crying, and screaming. This probably suggests that vocal expression of emotions is as important as, if not more important than, other biological forms of expression. It is believed that non-verbal expressions and emotive vocalizations existed before speech as a communicative and expressive channel [Ruch and Ekman, 2001]. Some researchers think that speech may have developed from non-verbal utterances such as laughter, crying, screaming etc. Prosodic features of air control, pacing, tone, and tenor become more exaggerated and emotions break through in musical representations while language regresses into babbling. In California, a purgative psychotherapeutic method called primal scream therapy was developed by Arthur Janov. A primal scream therapist encourages patients with emotional disorders to express their feelings by screaming in order (it is hoped) to re-live their birth experience. In Taiwan, a laughter club has recently been opened to encourage people to laugh and have better health and a happier life. Members start the laughing sessions by uttering voices like ho-ho-ha-ha followed by practicing around forty-one kinds of laughter including crazy laughter and Lion laughter (Figure 7). The laughter researcher, Robert Provine, made many discoveries during his study of the acoustic and rhythmic pattern of laughter. He noted that laughter consists of a series of vowel-like sounds each of which is 75 milliseconds long. These short sounds are repeated at regular intervals every 210 milliseconds [Provine, 1996]. Provine also discovered that there is a gender difference in the extent of laughter and that women laugh much more than men [Provine, 1996]. He noticed that the laughter is usually expressed like a vocal punctuation mark during a pause at the end of a phrase or utterance rather than occurring in the middle of an utterance. The use of laughter and other emotive vocalizations as means of social bonding has also long ago been suggested by Darwin. Another universal emotive vocalization is crying which usually occurs as an emotional response to pain, hunger, sickness, sadness, or even happiness. Crying is the first vocal expression and communication signal that a newborn generates. Pain crying, for instance, starts with a sudden cry that is followed by long cries and breathless pauses.
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Most often known cholesterol lowering foods generic atorlip-20 20mg on line, impairments are greatest for more recent events leading up to the injury or disease (Squire standard cholesterol ratio atorlip-20 20mg visa, 1992) cholesterol youtube purchase generic atorlip-20 from india. This produces a situation in which memory for more distant events what is your cholesterol ratio supposed to be purchase atorlip-20 visa, such as those in childhood how many cholesterol in eggs buy atorlip-20 discount, is actually better than memory for more recent events cholesterol definition chemistry buy cheap atorlip-20 20mg line. This is the reverse of what is found in those without retrograde amnesia cholesterol heart disease generic atorlip-20 20 mg online, who display superior memory for more recent events cholesterol lowering foods cinnamon order cheap atorlip-20 on-line. In addition, individuals with retrograde amnesia can often display a range of de cits in recalling pre-morbid memories. Interestingly, on some occasions de cits can be more severe for certain types of memory. When asked to recall an autobiographical memory many people report recalling visual images of the event or seeing what happened (Brewer, 1995). It is now thought that visual imagery may play an important role in the retrieval of memory for personal events and experiences (autobiographical memory) and that it enables us to mentally relive and re-experience our past (Rubin, Schrauf, & Greenberg, 2003). If this is true, then individuals who are de cient with respect to processing visual information may also have impaired access to their auto biographical memories and feel unable to relive those memories. His memories were simply lacking in the types of detail and recollective experience that make our memories of incidents and events so compelling. Why should visual imagery play such an important role in the retrieval of our past A neuroscienti c explanation relates to the way in which memories are stored and retrieved. Memories, especially autobiographical memories, are com plex and often involve the interplay of a number of di erent senses such as vision, audition, olfaction, etc. Damasio (1989) advanced a theoretical account that argued that the processing and storage of such a variety of infor mation takes place not in one neural region but across multiple regions, with each involved in processing a di erent aspect of the original event. When it comes to retrieving auto biographical memory then multiple neural regions become activated and provide the basis of our re-experiencing the event. These interacting regions can be seen as being dependent on one another and, as a consequence, damage to one region can e ectively disrupt the activation process from spreading to other neural regions. This may either prevent memory retrieval, or at least disrupt the retrieval of some of the details of the experienced event. In a review, Maguire (2002) reported that autobiographical retrieval leads to the acti vation of a network of areas including temporal and parietal regions, the medial frontal cortex, the cerebellum, and the hippocampus. Maguire claims that this is likely to be due to a number of factors such as the variety of means by which auto biographical memories are elicited, the relative recency of the memories, di er ences in the amount of e ort required to recall a memory, and the amount of time allowed for each recall and response. All these di erences make comparisons and generalisations quite di cult and clearly much research needs to be carried out in this important and interesting area. As mentioned earlier, patients with retrograde amnesia often display a tem poral gradient of memory loss a ecting more recent (vs more distant) memories. According to some researchers, the reason for this is that following the encoding of an event, memories undergo a slow consolidation process and this is dependent on the hippocampus (Squire, 1992; Teng & Squire, 1999). Consolidation processes work to make the memory stable and increase its strength and resistance to forgetting. More speci cally, it has been proposed that the hippocampus is responsible for retrieving only relatively recent memories. Following the passage of time, and the consolidation process, it becomes possible to retrieve memories independently of the hippocampus. For example, Zola-Morgan and Squire (1990) trained monkeys to dis criminate between a set of di erent objects over a period of weeks. Following lesions to the hippocampus the monkeys were tested on their memory for the previously learned objects. If the hippocampus is required for the retrieval of more recent memories, then lesions to this structure should produce a greater impairment for the most recently acquired objects. This was indeed the case: memory was most impaired for the objects learned a few days before and was best for those acquired weeks before. In humans, Bayley, Hopkins, and Squire (2003) presented amnesic individuals, whose pathology was limited to the hippocampal region, with the cue-word autobiographical memory test. They were asked to recall memories from the rst third of their lives prior to the onset of their amnesia. Compared to control participants, the quality and details of the memories retrieved were virtually identical. Thus it would appear that the recall of more distant memories is not dependent on an intact and fully functioning hippocampus. For example, Nadel and Moscovitch (1997) and Moscovitch and Nadel (1998) propose that the hippocampus is required for the retrieval of both recent and remote memories. They note that the temporal gradient of memory loss in some retrograde amnesia cases extends back decades, sometimes up to 30 years. They suggest it is implausible that any form of physio logical consolidation process would take this amount of time, extending some times over the entire life of the individual. Their alternative hypothesis is that the hippocampus is always involved in the encoding and retrieval of memories. Over time, memories are subject to reactivation with older memories, acquiring a greater number of reactivations. The reactivation process leads to multiple memory traces being formed within the hippocampus and surrounding cortex. When damaged, older (vs more recent) memories are more likely to be recalled because they are more resistant to loss as they possess multiple retrieval routes. Some recent neuroimaging work is consistent with the predictions of this theory: Bosshardt et al. The consolidation theory of Squire and colleagues would predict a smaller amount of activation over extended periods of time because older memories are hypothesised to be less dependent on the hippo campus. Presumably this process takes the form of cellular and molecular changes at the synaptic level. In spite of being beyond the scope of this chapter, the molecular and cellular basis of memory consolidation has been the object of intensive research and is worth mentioning here. This increased response can be shown to last for hours or months (Barnes, 1979) and thus represents the record of previous neuronal activity. The reason for this is an increase in protein synthesis in the postsynaptic neuron (Bourne et al. Effectively, this leads to a modi cation or strengthening of the synapse (Martin & Morris, 2002). Exactly how these cellular and molecular changes are re ected in the types of memory considered in this chapter is as yet unknown and represents a pressing challenge for neuroscienti c research. Through the careful analysis of individuals with brain damage, and with the use of neuroimaging procedures, it will be appreciated that the concept of memory does indeed encompass and support the idea of multiple memory systems and sub systems with multiple component processes. It is now clear that the human brain possesses the capacity to represent many different forms of information and that different neural regions performing different cognitive processes are responsible for this capacity. With respect to short-term memory, broad support has been gathered for the idea that multiple systems and processes are responsible for the maintenance and manipulation of information currently being processed. Neuroscienti c research has assisted in the development and re nement of models of short-term and working memory. By the careful analysis of those individuals with brain damage, the idea of a unitary short-term memory does not stand up to scrutiny: Different regions of the brain are, for example, responsible for maintaining and manipulating verbal information and visuospatial information. Neuropsychological work has also provided the impetus for revisions of the working memory model and the incorporation of the so-called episodic buffer. With respect to long-term memory, the idea of declarative and non-declarative memory has received considerable support. Furthermore, the precise nature of the subsystems and processes underlying these forms of memory is being worked out in ever ner detail. For example, non-declarative memory comprises a number of subsystems that dissociate from one another and are located in different neural regions. Declarative memory comprises a number of processes that enable conscious remembering of past events, and research suggests that these processes may be differentially dependent on different neural systems and pathways. Conscious recollection appears to be crucially dependent on the hippocampus, and vivid memories may require the additional involvement of neural regions involved in perception. Further growth will depend in part on the theoretical frameworks and ideas that we bring to bear on the empirical data, and on the discovery of new ndings that may challenge these frameworks and preconceptions. It is important at the outset to try to distinguish between sensory mechanisms of vision and perceptual processes that permit recognition of the visual input. The latter is what principally concerns us here, and we will consider research ndings from case studies of people who have lost certain perceptual functions, usually after damage or disease to key cortical regions, as well as ndings from functional brain imaging. In the retina, a network of cells interacts to provide the brain with evidence of contrast, colour, and boundaries (edges). Retinal output, in the form of millions of nerve impulses, travels via the optic nerve and tract to the lateral geniculate nuclei (one on each side) of the thalamus. Here, information from the two eyes begins to coalesce, with input from the central fovic retinal regions being separated from peripheral retinal regions. Cells in this region are arranged in columns and respond preferentially, and in some cases exclusively, to particular types of visual input, such as the orientation of lines, colour information, and so on. Thanks in no small part to the pioneering work of Hubel and Weisel in the 1960s and 1970s, the route from eye to brain is reasonably well understood. In order to begin to understand these stages of processing, we need to look beyond V1 and V2 of the occipital lobe to other cortical regions that are implicated in the interpretation of visual sensation. Separate cortical regions deal with colour and movement, and coordinate higher-order perceptual processes such as reading, object recognition, and facial recognition. Later in the chapter we introduce some brain disorders that seem to be anatomically and functionally linked to one or other stream. Normal visual perception can be studied more directly using functional imaging and we will also review some of this literature. The inferior route follows a ventral course (round the side and particularly underneath) into the temporal lobes, whereas the superior route takes a dorsal course (over the top) into posterior regions of the parietal lobes. It had two conditions: in the landmark task, monkeys learned to associate the presence of food in one of two food wells with a landmark such as a cone, which was always positioned near the baited well. After a period of learning the rule was reversed so that food now only appeared in the well farthest away from the cone. In the object discrimination condition, there were two landmarks such as a cone and a cube. In the training phase, food was only hidden in the food well near to one particular landmark, then when this had been learned, the relationship between cue and food was reversed. In the landmark experiment, monkeys learned to associate the presence of food in a well identi ed by a particular marker (in this case, a cylinder). Once learned, the rule was reversed so that now the food was in the well farthest away from the marker. Although control animals and those with temporal lesions quickly learned the reversal, animals with bilateral parietal lobe lesions failed to improve. In the object discrimination experiment, monkeys learned to associate the presence of food with one of two markers (say, the cube). Once learned, the rule was reversed and the food was now associated with another object (the cylinder). Monkeys with parietal lesions were untroubled by this reversal, whereas those with bilateral temporal lobe lesions took several trials to learn the new association. However, her visually guided action towards an object (to grasp it for example) was normal. Conversely, patients with optic ataxia have preserved object recognition but cannot use visual information to guide their actions, leading to grossly defective grasping/reaching skills. This condition is almost always associ ated with damage to the superior parietal lobule (Battaglia-Mayer & Caminiti, 2002). However the details of the model have been amended as our knowledge of cortical functions has increased. Anatomically, it is clear that more cortical modules are involved in the two streams than was initially thought. It is therefore possible that this route would be important in the integration of perceptual information about stimuli arising from di erent sensory inputs, such as hearing and touch (Boussaoud, Ungerleider, & Desimone, 1990). Conceptually, the main challenge to the model has concerned the nature of information processing in the dorsal stream. Originally, Ungerleider and Mishkin proposed that this stream was dedicated to the identi cation of object location in space. In other words, while knowing about the location of objects is an important component, some neurons in this pathway become particularly active only when a visual stimulus prompts a motor response, such as reaching for an object. The guidance that cannot be inferior parietal lobule, on the other hand, is known to be associated with a range explained by motor, somatosensory, or primary of visuospatial skills (some of which we describe later in this chapter) not directly visual de cits. Creem and Polysensory: Responsive to Pro tt have characterised these as involving the manipulation of non-egocentric input from several modalities. While debates about, and re nements of, the model are likely to continue for some time, the basic principle of separable dorsal and ventral processing streams for visual perception, specialised for what and where (or how), has become accepted as a tenet of brain organisation. In fact, recent evidence suggests that the same what/where segregation may be an organisational principle that extends to other perceptual domains such as audition (Alain et al. However, many neuropsychologists anticipate further revisions to the model as more is learned about the nuances of visual perception. We return to consider spatial processing in the dorsal stream later in this chapter. For the time being, we need to consider some of the characteristics of the ventral stream, and the effects that damage to different components of it can have on object recognition. For example, 3D objects in our eld of vision are projected onto our retinas, which only work in 2D. Second, objects must be recognised as such irrespective of where their image falls on the retina, their distance from the viewer, and their orientation. For example, a tree is still usually perceived as a tree whether it is close to you or on the distant horizon. Third, you must also be able to recognise objects when they are moving in 182 Chapter 8 Visual object recognition and spatial processing di erent directions. A horse moving across your line of vision projects a quite di erent image from one galloping directly towards you. Finally, your brain must be able to link the percept (of the horse for example) with stored representations of horses in order for you to make the semantic leap towards recognition of the object as a horse. The ventral stream runs bilaterally from area V1 of the occipital lobes via areas V2 and V4 into the inferior regions of the temporal lobes (see Figure 8.
These machines are useful then in screening for strabismus and signi cant opacities in the visual system as well as signi cant refractive errors high cholesterol definition wikipedia cheap 20mg atorlip-20 fast delivery. Occasionally subjective measurements of vision are impossible and the exami nation must rely primarily on objective measurements such as the physical exami nation of the ocular structures with particular attention to the cornea cholesterol test eating order atorlip-20 20mg free shipping, lens cholesterol lowering drugs purchase discount atorlip-20 online, refractive status cholesterol level chart by age buy atorlip-20 20 mg mastercard, motility status cholesterol chart mmol purchase generic atorlip-20 line, the optic nerve cholesterol level chart in malaysia cheapest generic atorlip-20 uk, and retina level of cholesterol in shrimp purchase cheap atorlip-20 line. When the ophthalmic examination alone does not provide adequate explanation for a degree of visual impairment definition of no cholesterol purchase 20 mg atorlip-20 amex, further testing must be done. Visual evoked potentials can provide quantitative information useful in predicting visual acuity. Examinations must be performed at birth or at the time of initial diagnosis, and repeated periodically to review ndings (see Table 18. However, consistent follow-up is of utmost importance, and guidelines are being developed [14]. Common Causes of Vision Impairment Refractive errors include hyperopia, myopic, and astigmatic errors. Ametropia or uncorrected refractive errors are common in the general population and in chil dren with neurodevelopmental disorders even more so. While mild hyperopia is the normal refractive state 18 Vision Impairment 287 Table 18. Eyes with extreme hyperopia may tend to have shallow anterior chambers and crowded optic nerves, which is occasionally mistaken for papilledema. Myopia is less frequently encountered in preschool children, but tends to increase in school-age children, as the eye enlarges. Children with exotropia or convergence issues tend to bene t even from mild myopic prescriptions. High myopia is also associated with retinal detachments and can be associated with certain syndromes. Severe astigmatism is not a common nding in early childhood, but irregularities of the cornea due to birth trauma or congenital malformations of the cornea can cause astigmatism. Toddlers who have more than two diopters of astigmatism should have glasses, even in the early nonverbal period, in order to prevent amblyopia. Finally the situation in which there are signi cant differences in the refraction of the two eyes is known as anisometropia. Bergwerk Amblyopia Amblyopia is caused by the lack of a clear image falling on the retina of a young child. Strabismic amblyopia occurs where an eye is deviated and therefore the image does not fall on the fovea. Deprivation amblyopia is due to a blockage of the transmission of light to the retina. This can be due to an opacity in the visual axis, such as congenital clouding of the cornea, or a congenital cataract. Refractive amblyopia can be divided into anisometropic amblyopia or ametropic amblyopia. Anisometropic amblyopia is unilateral in which there is a signi cant difference in the refraction of the eyes, and ametropic amblyopia is due to a high refractive error in both eyes. As visual acuity develops rapidly in the rst few years of life, anything that interferes with the development of a clear retinal image can cause amblyopia. After the rst decade of life, a child is no longer at risk for amblyopia as cortical plasticity is generally over by that age. Conversely, the younger amblyopia is discovered and treated, the better the result. Strabismus Strabismus is a common ocular problem in children and should be addressed as early as possible. In the general population esotropia is much more common than exotropia and vertical types of strabismus are much rarer. Children with hypotonia, cerebral palsy, or other neurodevelopmental issues have a higher incidence of strabismus. Premature chil dren even without retinopathy of prematurity have a higher incidence of strabismus as well. Prior to age 6 months intermittent or mild deviations of the ocular align ment may be within the range of normal, but by age 6 months any misalignment requires evaluation and treatment. Parents tend to notice signi cant strabismus and bring it to the attention of their primary care provider. Occasionally children with very wide epicanthal folds have pseudostrabismus or pseudoesotropia, where they appear esotropic, but as the nose develops, the patient will appear normal. These children still require close follow-up to rule out the development of true strabismus. Children with congenital esotropia present early due to the generally large angle of their strabismus. The treatment for congenital esotropia is surgical with follow-up afterward, as frequently glasses are needed to maintain the surgical alignment results. Addressing the cause of the deprivation is vital, prior to repair of the strabismus. Accommodative esotropia is due to the presence of high hyperopic refraction and this may be ameliorated by the use of hyperopic glasses. Children with developmental delays or neurologic impairment tend to have more frequent exotropia. Cataract Cataracts can be congenital, syndromic, age related, traumatic or occur with med ical conditions such as diabetes or medications, and treatment such as steroids or radiation. The treatment for cataracts is surgery in which the cloudy lens which is obstructing the visual axis is replaced with a synthetic lens. While extraction of the cataract and implantation of an intraocular lens is the standard treatment in older children and adults, an intraocular lens may not be implanted in very small children. This is due to the small size of the eye and the rapid growth that ensues in the toddler years, making not only the surgery but also the refractive needs challenging. From approximately age 5 years and upward, there is no controversy and a lens is implanted. Occasionally spectacles are still needed to correct residual refractive needs including presby opia. Cataract is the leading cause of blindness worldwide, therefore screening for cataracts and making surgery available is a high priority. Examples of Speci c Clinical Entities Down Syndrome Down syndrome is the most common chromosomal anomaly accounting for intel lectual disability occurring at a prevalence rate of 9. The prevalence of Down syndrome is increasing, especially in children born to mothers over age 35 [16]. Variations in the exact prevalence of ndings occur depending on the study population involved; however, all studies demonstrate 290 K. Although exact statistics vary according to the population studied, Down syndrome children of school age have a high percentage (43%) of signi cant refractive errors [18]. Signi cant levels of refractive errors tend to increase with increasing age and doubled in school-age children [21]. As stated previously, these issues can all be potentially treated to provide increased visual performance. Children with Down syndrome were found to tolerate their spectacle correction well including bifocals as needed for issues of accommodation. In addition con ditions such as nasolacrimal duct obstruction or blepharitis which both occur in approximately 30% can be treated as well. The pres ence of cataract and strabismus increased with age, and therefore screening methods and examination must include regular assessment of vision, motility disturbances, and examination of the red re ex or fundus. In England, the United Kingdom Down Syndrome Medical Interest Group saw that with increased stringency of screening according to published guidelines, screening ef cacy improved from 66 to 100%, with the advantages of earlier cor rection of refractive errors found. By enforcing screening at age 3 years, Down syndrome had refractive correction at age 3. The percentage of children with abnormalities increased from 38% in the rst year of life to 80% in school-aged children. They recommend examination at birth or at earliest diagnosis in the rst 6 months of life followed by annual examination by a pediatric ophthalmologist [22]. Finally adults with Down syndrome are at increased risk of premature age-related changes from issues such as cataract and keratoconus. The damage depends on at what age the insult occurred, as different areas of the brain are affected at these time intervals. As well the degree of hypoxic/ischemic injury is also crucial in determining the extent of damage. Perinatal hypoxia is the most common cause in 35%, while prematurity (29%), hydrocephalus (19%), anatomic abnormalities of the central nervous system (11%), and seizures (10%) are other primary causes, with encephalitis, meningitis, and trauma being other causes [23]. Children with cortical visual impairment have a wide range of visual disability ranging from mild vision loss with cognitive visual dysfunction due to damage to the prestriate cortex, to the severe extent which may have total blindness or no light perception vision [24]. Many patients with cortical visual impairment have dif culty performing classic Snellen visual acuity due to associated neurologic impairment. Strabismus was found in the majority of patients, with exotropia (40%) being more common than esotropia (19%). In addition nystagmus and high refractive errors were found in approximately 20% each. The patients who had better prognosis were those who had initial better visual function. A signi cant portion of patients in both studies did demonstrate some improve ment in vision. Additional Aspects of Treatment Identi cation of visual impairment is a crucial to ensure optimal development and functioning. Once patients have been identi ed as having a diagnosis, treatment should be instituted immediately. Congenital lesions such as congenital cataracts or congenital glaucoma must be addressed as early as possible, even in the rst few weeks of life as soon as anesthesia is medically appropriate. However, even with successful surgical outcomes, the development of adequate vision will not develop unless there is consistent follow-up and treatment in a team-oriented manner. In addition the primary physician must be involved for issues such as antibiotic regimen consultation or for follow-up if medications such as steroids are indicated after surgery. An optometrist and optician trained speci cally in pediatric issues are crucial as well to deal with issues of spectacles and patching. As an example, a child who had congenital cataract surgery and requires glasses which should sit properly. Appropriate t for spectacles is crucial as well in children who in addition to ocular issues have hearing aids or abnormalities of the ears, or facial asymmetry, which may be of consideration in syndromic children or adults. Amblyopia therapy requires again a team approach with the ophthalmolo gist/optometrist/orthoptist team as well as with the family members or caretakers and the educational institution in which the child is schooled. Then appropriate glasses must be t so that a well-focused image falls on the retina. Finally, once a child has adjusted to wearing spectacles, occlusion of the intact eye must be performed to encourage use of the amblyopic eye. This is generally done by patching the better eye on a sched ule set by the ophthalmologist. Some children do not tolerate patching and then penalization with blurred glasses or atropine drops is instituted. Patching used to be prescribed on a full-time basis, but recent evidence by the Amblyopia Treatment 18 Vision Impairment 293 Studies demonstrates that adequate results may be obtained with part-time patching such as 6 h daily for severe amblyopia [27] and that 2 h daily may be suf cient in mild to moderate amblyopia [28]. These studies also discussed that recurrence is common and it is better to taper patching than to stop abruptly. Treatment success is inversely related to age, therefore early detection and initiation of treatment is vital to developing normal vision [29]. Lack of compliance is a very common issue even in children without intellec tual disability or other medical issues and is more of an issue for a child with multiple sensory issues such as hearing loss or intellectual disability. Families need encouragement as frequently children are initially very resistant to patching therapy. Ideally strabismus and amblyopia in children are best addressed as soon as identi ed, due to the plasticity of the neurologic system. For example, unilateral amblyopia in a 1-year old can be corrected in early infancy in 1 week of consistent patching, whereas a 7-year old who refuses to wear a patch during school and is only patched for an hour or so after school at home may require extended months of treatment to reach the endpoint of equal visual acuity or free alternation of xation. Occasionally patching treatment fails due to poor cooperation on the part of the child. In children with develop mental delays or intellectual disability this period may last longer. Part-time patching or optical degradation such as putting tape over the glasses in front of the stronger eye are less effective but sometimes may allow better cooperation. Maintenance therapy has been showed to be of high value according to recent results of the Amblyopia Therapy Study. Finally in extremely dif cult childhood cases, results may occasionally still be achieved in the adolescent years albeit with prolonged efforts. In all cases, close follow-up is necessary and the parents and teachers must know to watch for recurrence of strabismic deviations or change in xation preference of the eyes. Recurrence or backsliding occurs not infrequently and then resumption of therapy is indicated. In older children and adults, cataracts should be addressed when found to be visu ally signi cant. Occasionally it is dif cult to assess the degree of cataract related impairment and tools as a questionnaire of the impact on the activities of daily liv ing are useful. Bergwerk attentive than previously, seems to have less interest in television or food, or has more glare and tends to avoid sunlight, or is falling more than usual and having dif culty navigating stairs. Close coordination needs to occur between the surgeon, the primary medical physi cian, and the care givers or family member to insure the success of the surgery. It is not infrequent to nd that a patient had successful surgery but then adequate results were not achieved or complications ensued due to dif culties with instilling med ications, maintaining patching, preventing a patient from itching, head banging, or dif culty in follow-up. Conclusions Neurodevelopmental disorders may occur in association with alterations in all aspects of the visual system. These vision issues can then have severe detrimental effects on the overall development of the child with decreased social, emotional, and communication skills in addition to the educational impact. While an all encompass ing review of vision impairment in children with neurodevelopmental disabilities is daunting in scope, the varied causes of decreased vision in children with neurode velopmental disabilities have been discussed. As well the dif culties in screening and evaluating these patients are obvious; nevertheless the need to do so is crucial to their well-being. New tools for assessment of vision which are easy and effective need to be developed for use in this population. Screening programs in clinics or residential settings have been shown to be effective. A study among residents at a facility in Scotland demonstrated that prior to initiation of a comprehensive screening, only 11% of patients had been offered vision assessment in the previous 5 years. Other than pro foundly impaired patients, an assessment of vision using the variety of methods discussed earlier was achieved. Resources now are becoming more available in the developed world for persons with decreased vision. Vision rehabilitation serves are best provided by a multidisciplinary team which may include the primary care physician, ophthalmologist, optometrist, orthoptist, social worker, nurses, rehabilitation therapists or counselors, and orientation and mobility specialists. Resources such as Lighthouse International, Prevent Blindness America, or the Helen Keller Foundation can provide resources such as online materials or 18 Vision Impairment 295 support groups of national or local nature. Research must continue to provide further detailed information on epidemiologic data in the population with intellectual disability. Checklists for caretakers to assess vision or questionnaires to assist in assessing vision need to be developed for this population and schedules for effective and screening need to be implemented. The goal is to help all children with or without developmental disabilities to maximize their potential and enjoy a fully active life. Vision care requirements among intel lectually disabled adults: a residence-based pilot study. Visual impairment in adult people with moderate, severe, and profound intellec tual disability. Global magnitude of visual impairment caused by uncorrected refractive errors in 2004.
