1/25. Establishing joint visual attention and pointing in autistic children with no functional language.Joint visual attention is defined as looking where someone else is looking. The purpose of this study was to examine the conditions for establishing joint visual attention in autistic children who have no functional speech. An experimenter, sitting facing the child, looked at one of six pictures near the child. Analysis showed that joint visual attention to stimuli behind the child and therefore outside of the visual field occurred at a higher rate when the visual angle between the stimuli was about 60 degrees. Spontaneous pointing at the target object increased with training which included feedback and physical guidance. These results are discussed in terms of the effects of environmental variables and perceptual mechanisms on the emergence of joint visual attention in autistic children. The possibility of using an adult's social cues and expanding the child's visual field as a remedial procedure is also addressed.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
2/25. Impaired short temporal interval discrimination in a dyslexic adult.The ability to discriminate short temporal intervals was examined in a dyslexic adult (E.C.) and six matched controls. Listeners had to decide whether the second interval was shorter or longer than a standard (target) interval. Each interval was defined as the silent duration between two successive brief tones. Eight target intervals were used, ranging from 100 to 1,200 ms in duration. At each target interval, the differential threshold (DL) for duration was assessed, with the use of an adaptive psychophysical procedure. The results show that E.C.'s differential threshold values were much larger than those of controls. Moreover, the slope estimates covering the duration range from 100 to 800 ms indicated that in comparison to controls, E.C.'s differential threshold increased dramatically as the target duration increased. Thus her timing impairment becomes more pronounced with increasing duration. This timing deficit is consistent with other studies that have found temporal processing deficits associated with dyslexia.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
3/25. Multiple reference frames in neglect? An investigation of the object-centred frame and the dissociation between "near" and "far" from the body by use of a mirror.In this single case study of a man (AE) who suffered a right hemisphere stroke we showed the co-existence of neglect within different spatial frames: (a) In left hemispace and (b) in 'far' versus 'near' space, both as defined from the patient's viewpoint, as well as (c) for the left side of an object (as defined from an object-centred view). In the experiment, AE's latencies to name the colour of two cubes, each located in one hemispace, were measured. In some conditions, the cubes were placed on a table but in other conditions each cube was held in one hand of an experimenter who could either face the patient or show the cubes while her back was turned towards him. One prediction was that AE would show longer latencies for cubes in left hemispace; however, if object-centred neglect also occurred, then latencies should be even longer for cubes held in the experimenter's left hand. In order to reveal the presence of neglect for 'far' versus 'near' space, the cubes could also be positioned either near to (i.e. reaching distance) or far from the patient (i.e., several metres out of reach), by moving the table or the experimenter. Finally, in some conditions, AE looked at the cubes into a mirror that was positioned far away from his body. Because external objects seen in a mirror can be 'near' the patient's body, the patient actually looked at a 'far' location (i.e. the surface of the mirror) to see an object that is 'near'. The experiment confirmed the presence of all forms of neglect, since AE not only named the colour of a cube seen in his left hemispace more slowly than in right hemispace, but latencies increased for a cube held by the experimenter in her left hand and in left hemispace (both when the left hand was seen directly or as a mirror reflection). Finally, AE's performance was worse for 'far' than 'near' locations, when the cubes were physically located near his body (i.e., within "grasping" space) but seen in the mirror.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
4/25. Exacerbation of psychosis by misinterpretation of physical symptoms.Impaired processing of perceptual information is often a prominent aspect of psychotic disorders. Physical symptoms such as pain or discomfort may be either incorrectly perceived or misinterpreted by psychotic patients. Presented here is a series of cases in which somatic symptoms occurred in psychotic patients and worsened their psychotic states but only later were recognized as physical problems. Psychotic patients may be unable to comprehend or describe their physical symptoms adequately. Physical disorders of psychotic patients may be overlooked if clinicians are not vigilant and thorough in assessing the patients' complaints, especially if such complaints sound delusional or bizarre.- - - - - - - - - - ranking = 6keywords = physical (Clic here for more details about this article) |
5/25. Can spatial and temporal motion integration compensate for deficits in local motion mechanisms?We studied the motion perception of a patient, AMG, who had a lesion in the left occipital lobe centered on visual areas V3 and V3A, with involvement of underlying white matter. As shown by a variety of psychophysical tests involving her perception of motion, the patient was impaired at motion discriminations that involved the detection of small displacements of random-dot displays, including local speed discrimination. However, she was unimpaired on tests that required spatial and temporal integration of moving displays, such as motion coherence. The results indicate that she had a specific impairment of the computation of local but not global motion and that she could not integrate motion information across different spatial scales. Such a specific impairment has not been reported before.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
6/25. The role of occupational therapy in rehabilitating stroke patients.The role of the occupational therapist is outlined. An overview of occupational therapy evaluation and treatment is discussed. The goal of rehabilitation is aimed at helping the patient achieve the highest level of independence of which he is physically capable. A case report is presented.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
7/25. Misprojection of landmarks onto the spatial map.It has been suggested that neglect patients misrepresent the metric spatial relations along the horizontal axis (anisometry). The "fabric" of their internal spatial medium would be distorted in such a way that physically equal distances appear relatively shorter on the contralesional side (canonical anisometry). The case of GL, a 76-year-old lady with left neglect on visual search tasks, is presented. GL showed severe relative overestimation on the left (contralesional) side on two independent tasks evaluating the metrics of her internal representation. A qualitatively similar pattern was found in two out of 10 other neglect patients who performed the second task. This behavior cannot be accounted for by the canonical anisometry hypothesis. Nevertheless, GL produced a relative left overextension (underestimation) when trying to set the endpoints of a virtual line given its midpoint (Endpoints Task). An interpretation of these results is offered in terms of a misprojection of relevant landmarks onto the internal representation without assuming distortion of its "fabric."- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
8/25. Covert processing of visual form in the absence of area LO.The patient D.F., who suffers from severe visual form agnosia, has been found to have a bilateral lesion of area LO, an area known to be intimately involved in the perception of object shape. Despite her perceptual impairment, however, D.F. retains residual form processing abilities that can provide distal visuomotor control, for example in the configuration of her grasp when reaching to pick up objects of different shapes and sizes. This dissociation has been interpreted as reflecting the sparing of a dedicated system for processing the physical properties of objects solely for purposes of guiding action. Here we test this hypothesis in two studies designed to examine whether or not spared shape processing capacities might be revealed under other kinds of indirect test conditions. First, we exploited the fact that a redundant shape cue will speed search for a coloured stimulus within an array, and vice versa. Unlike our control subjects, D.F. showed no facilitation effect of either kind. Second, we used two Stroop tasks in which single coloured uppercase letters were presented. Our intention was to determine (a) whether naming the colour would be influenced by whether the letter was the initial letter of the correct or incorrect colour name (e.g. 'R' or 'G'); and (b) whether the reverse might be true, that is that D.F.'s guesses at letter identity might be influenced by their colour. We found no evidence for a Stroop effect of the former (standard) kind in D.F., but we did find evidence for reverse-Stroop effects. This result may reflect a partial sparing of ventral stream areas specialised for letter-form processing.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
9/25. Progressive posterior cortical dysfunction: a clinicopathologic series.BACKGROUND: Atypical presentations of neurodegenerative dementing disorders include the syndrome of progressive posterior cortical dysfunction (PPCD) involving selective higher order visuospatial deficits. The neuropathologic correlates of PPCD remain poorly defined. methods: This is a retrospective case series of 27 individuals (14 men, 13 women) diagnosed clinically with PPCD. Participants were either enrolled in the Alzheimer's Disease research Center (ADRC) or referred to the memory diagnostic center of an urban academic medical center. Clinical evaluations included physical and neurologic examinations, the Clinical dementia Rating (CDR), and psychometric measures. Neuropathologic examinations were completed in 21 individuals with PPCD. Psychometric measures from 65 individuals with mild dementia of the Alzheimer type (DAT) enrolled in the ADRC were used for comparison. RESULTS: Neuropathologic etiologies of PPCD were alzheimer disease (AD) (n = 13), AD plus parkinson disease (n = 1), AD-Lewy body variant (n = 2), dementia with lewy bodies plus progressive subcortical gliosis of Neumann (n = 1), corticobasal degeneration (n = 2), and prion-associated diseases: Creutzfeldt-Jakob disease (n = 1) and fatal familial insomnia (n = 1). Confirming the clinical impression, psychometric profiles for individuals with PPCD differed from those of people with DAT alone and revealed disproportionate deficits on measures of visuospatial ability. CONCLUSIONS: AD was the most frequent cause of PPCD in this series, although non-Alzheimer's dementing disorders also should be considered.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
10/25. Synaesthesia: discordant male monozygotic twins.Grapheme-color synaesthesia, a condition in which achromatic graphemes elicit vivid experiences of color is believed to be a genetically determined trait. We describe a study of 10-year-old twin brothers who are physically identical in appearance but who have considerably different conscious experiences. A phenotypic analysis that measured the consistency of grapheme-color pairings over test-retest confirmed that one twin has grapheme-color synaesthesia and the other twin does not. A genotypic analysis using sixteen microsatellite loci confirmed that the twins are monozygotic. These findings are problematic for previous suggestions that synaesthesia is an X-linked dominant trait. At the very least, the findings show that the penetrance of the genotype for synaesthesia is incomplete and that any view suggesting that synaesthesia is simply an X-linked dominant trait is therefore also incomplete and possibly even incorrect. The findings also negate a previous suggestion, based on a study of female monozygotic twins, that discordance of synaesthesia in identical twins is due to X-inactivation. In general, the findings raise serious questions regarding whether it is possible at this time to establish the genetic contribution to synaesthesia.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
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