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PubMed1998

Backward masking in schizophrenia: time course of visual processing deficits during task performance.

Backward masking deficits have been put forward as potential psychological markers for vulnerability to schizophrenia. This study was conducted to investigate whether schizophrenic patients improve their performance on a backward masking task during a single test session. The ability of a degraded stimulus version of the masking task to act as a specific diagnostic marker for paranoid schizophrenia (versus affective disorder) was also investigated. The backward masking task was performed on 18 paranoid schizophrenic patients, 18 unipolar depressed patients, and 18 non-psychiatric controls. Paranoid schizophrenic patients were included because they tend to show normal performance with traditional masking protocols. Schizophrenic patients made significantly more detection errors compared to depressives and non-psychiatric controls where interstimulus intervals (ISIs) longer than 14 ms were used. Unlike depressed patients and non-psychiatric controls, schizophrenic patients showed no reduction in error rate during the entire period over which the backward masking task was performed. The constant error rate which was observed at an ISI of 114 ms suggests that schizophrenic patients cannot attenuate the disruption effect due to deflection of attention from the target to the mask. The backward masking deficit in schizophrenia appears to arise from a temporarily stable visual processing impairment in performance within a single test session.

Adult↗
PubMed1978

Cognitive and perceptual differences between schizophrenics and organics.

Distinguishing between brain-damaged and schizophrenic patients remains a significant clinical problem. However, substantive and methodological difficulties have led to discouragement and consequent loss of interest in this area of differential diagnosis. Several models for making this distinction were proposed: cognitive, empirical-psychometric, attentional motivational, neuropsychological and information processing. In evaluating these models, three persistent methodological problems were identified: diagnostic inaccuracy, inadequate sampling, and difficulty in interpretation of the subject's performance. Various suggestions were made for resolving these difficulties through such means as equating samples for level of deterioration, utilizing modern, objective diagnostic techniques in the selection of samples, comparing subtypes of brain damage and schizophrenia, and using test procedures that have been shown to assess dispositional characteristics of the conditions under study, rather than their epiphenomena. It was suggested that recent substantive findings, mainly those involving neurological deficit in schizophrenia and detection of major behavioral differences among various subtypes of schizophrenia and brain damage, could be used in attempts to resolve the differential diagnostic problem under discussion. It was suggested that resolution of the methodological problems posed in combination with new substantive data concerning schizophrenic and brain-damaged patients may set the stage for a new start for investigating an old problem.

Attention↗
PubMed1998

Visual-motor, visual-perceptual, and fine motor outcomes in very-low-birthweight children at 5 years.

The prevalence and severity of visual-motor deficits and the relation of visual-motor function to visual perception and fine motor skills was examined in a group of 83 neurologically and intellectually normal (IQ >84) very-low-birthweight (VLBW) children at age 5. Fifteen children (17%) had below average visual motor scores (<1SD below mean). While relatively few children (N=9) had below average scores in visual perception (11%), 58 (71%) had below average scores for fine motor skills. Nineteen (23%) were considered impaired (<1.5SD); of these, eight were severely impaired (<2SD). Fine motor scores were significantly lower in children who had been born <28 weeks' gestation, with hyaline membrane disease, or had required a longer period of ventilation. There was significant correlation between visual-motor and fine motor scores (r = 0.50, P < 0.001) and between visual-motor and visual perception scores (r = 0.42, P < 0.001). The implications of these findings and management of these 'normal' children need further research. Previous reports of visual-motor dysfunction in school-age VLBW children could be related to fine motor difficulties.

Apgar Score↗
PubMed1998

Reversal of vision metamorphopsia: clinical and anatomical characteristics.

BACKGROUND: Metamorphopsia is a visual illusion that distorts the size, shape, or inclination of objects. Reversal of vision metamorphopsia (RVM) is a rare transient form of metamorphopsia described as an upside-down, 180 degrees rotation of the visual field in the coronal plane. The pathophysiological characteristics of RVM remain unclear. DESIGN: Patients with RVM had a complete neurologic examination during or shortly after an episode of metamorphopsia, with particular emphasis on gaze disorders, visual fields, visually guided hand movements, and perceptual or cognitive deficits. Workup included imaging studies, visual field examinations, and brainstem auditory and visual evoked response. SETTING: Department of Neurology, Hadassah University Hospital, Hebrew University-Hadassah Medical School, Jerusalem, Israel. PATIENTS: Six consecutive patients were evaluated from 1991 to 1996. RESULTS: Five patients had parieto-occipital brain insult sparing the primary visual cortex, and 3 also had evidence of a concomitant brainstem or cerebellar syndrome. One patient had pure brainstem syndrome underlying the RVM. Three patients had complete RVM as well as oblique RVM of less than 180 degrees. CONCLUSIONS: These cases imply a possible anatomical localization of the central integrator of visual extrapersonal orientation. Our observations suggest that a separate central mechanism of visual orientation might exist in each cerebral hemisphere and that occipital and parietal lesions that spare the optic radiations may account for the oblique and complete RVM. We postulate that failure to perceive space in an allocentric coordinate frame, particularly in the coronal roll plane, is potentially the critical event underlying RVM.

Aged↗
PubMed1981

Span of apprehension deficits during the postpsychotic stages of schizophrenia. A replication and extension.

Thirty-five schizophrenic and 20 manic-depressive outpatients and 20 normal controls were administered a measure of visual information processing, the span of apprehension. The schizophrenic outpatients made significantly fewer correct detections of the target stimuli than did the manic-depressives and normal controls, particularly for conditions in which the target stimuli were embedded in four and nine irrelevant stimuli. A subgroup of schizophrenics produced the overall group differences. In a comparison of a subgroup of schizophrenics who showed impaired performance on the ten-letter array with the remaining schizophrenics, the ten-letter array appeared to be tapping processes that are independent of overall adjustment, the presence of particular symptoms, premorbid social adjustment, general demographic characteristics, and the presence of generalized performance deficits. The span of apprehension may be a marker for some subgroups of schizophrenia.

Adult↗
PubMed2001

Abnormalities of spatial and temporal sensory discrimination in writer's cramp.

Clinical observations of patients with writer's cramp suggest that abnormalities of the sensory system may be a frequent finding in this disorder. Neurophysiological data from an animal model of focal dystonia have revealed cells in somatosensory cortex with enlarged and overlapping tactile receptive fields. However, psychophysical studies so far have been unable to document a clinical correlate supporting a similar enlargement of receptive fields in humans. We compared the fingertip discrimination of the orientation of fine spatial gratings between writer's cramp and control subjects and found a significant decrease in grating sensitivity in the patients, consistent with the possibility of enlarged tactile receptive fields. In addition, we duplicated previous experiments showing an abnormality of tactile temporal discrimination. The results provide psychophysical measures which may relate to the development of sensory cortical reorganization in patients with writer's cramp.

Adult↗
PubMed1993

Slippage in the unity of consciousness.

Many psychological studies assume a unity of consciousness. Doubt is cast on this assumption (a) by psychophysical studies in normal subjects and those with blindsight showing the simultaneous dissociation of different modes of report of a sensation, and (b) by clinical studies of anosognosic patients showing dissociations of awareness of their own states. These and other phenomena are interpreted to imply two kinds of division of consciousness: the separation of phenomenal experience from reflexive consciousness and the non-unity of reflexive consciousness. Reflexive consciousness is taken to be necessary for report and is associated with the self as the subject of experience and agent of report. Reflexive consciousness is operative only when we attend to our own states. When we are involved in the world reflexivity intervenes less and our consciousness is more unified.

Awareness↗
PubMed2002

Spatial working memory deficits in schizophrenia patients and their first degree relatives from Palau, Micronesia.

Spatial working memory deficits associated with dorsolateral prefrontal dysfunction have been found in Caucasian samples of schizophrenia patients and their first-degree relatives. This study evaluated spatial working memory function in affected and unaffected members of multiplex schizophrenia families from the Republic of Palau to determine whether the spatial working memory deficits associated with schizophrenia extend to this non-Caucasian population. Palau is an isolated island nation in Micronesia with an elevated prevalence of schizophrenia and an aggregation of cases in large multigenerational families. Our objective was to evaluate the potential for spatial working memory function to serve as one of multiple endophenotypes in a genetic linkage study of these Palauan schizophrenia families. A spatial delayed response task requiring resistance to distraction and a sensorimotor control task were used to assess spatial working memory in 32 schizophrenia patients, 28 of their healthy first-degree relatives, and 19 normal control subjects. Schizophrenia patients and their relatives were significantly less accurate than normal control subjects on the spatial delayed response task but not on the sensorimotor control task. On both tasks, patients and relatives were slower to respond than the normal controls. There were no age or gender effects on accuracy, and working memory performance in schizophrenia patients was not significantly correlated with medication dosage. In summary, spatial working memory deficits that have been found in Caucasian schizophrenia patients and relatives were confirmed in this isolated Pacific Island family sample. These results suggest that spatial working memory deficits may be a potentially useful addition to the endophenotypic characterization of family members to be used in a comprehensive genome wide linkage analysis of these Palauan families.

Adult↗
PubMed1978

National Society for Autistic Children definition of the syndrome of autism.

It is helpful for the new student of autism to know the clinical and research basis from which our definition of the syndrome has been evolved. The main features and characteristics are no less meaningful for being recognized as working definitions, subject to alteration with the discovery of new knowledge about causation and treatment. Such research can be most useful, even when samples of autistic children with different specific characteristics are selected. However, it is necessary for the specific characteristics, and their selection purpose, to be identified explicitly. Likewise, the limits of applying the findings on such subsamples to other autistic children should be frankly acknowledged.

Adolescent↗
PubMed2006

[Auditory processing disorder versus attention deficit/hyperactivity disorder. A dysfunction complex or different entities?].

BACKGROUND: It has been suggested that auditory processing disorders (APD) and attention deficit/hyperactivity disorders (ADHD) may be the same entity with slightly differing symptoms. For testing this theory we compared parents' ratings of APD and ADHD behavioural characteristics. METHODS: A retrospective study was carried out with parents rating 312 children (113 girls and 199 boys; 6.0-9.11 years old, nonverbal intelligence IQ 95 or above) using APD and ADHD questionnaires. RESULTS: Significant, albeit weak correlations between several APD and ADHD subscale scores were found. Correlations between selective listening and attention behaviours approximated clinical relevance (rho >0.4). Factor analysis revealed two factors with APD behaviour loading on one and ADHD behaviour on a second different factor. Using a categorical approach, it appears that ADHD children have significantly more APD problems than children without ADHD. DISCUSSION: These data are consistent with the hypothesis that APD and ADHD overlap partly while still being distinct entities. In addition to dimensional aspects, the parents' rating may provide a guideline for establishing a diagnosis based on categorical distinctions.

Attention Deficit Disorder with Hyperactivity↗
PubMed2001

Disordered recognition of facial identity and emotions in three Asperger type autists.

In this report we aim to explore severe deficits in facial affect recognition in three boys all of whom meet the criteria of Asperger's syndrome (AS), as well as overt prosopagnosia in one (B) and covert prosopagnosia in the remaining two (C and D). Subject B, with a familially-based talent of being highly gifted in physics and mathematics, showed no interest in people, a quasi complete lack of comprehension of emotions, and very poor emotional reactivity. The marked neuropsychological deficits were a moderate prosopagnosia and severely disordered recognition of facial emotions, gender and age. Expressive facial emotion, whole body psychomotor expression and speech prosody were quasi absent as well. In all three boys these facial processing deficits were more or less isolated, and general visuospatial functions, attention, formal language and scholastic performances were normal or even highly developed with the exception of deficient gestalt perception in B. We consider the deficient facial emotion perception as an important pathogenetic symptom for the autistic behaviour in the three boys. Prosopagnosia, the absent facial and bodily expression, and speech prosody were important but varying co-morbid disorders. The total clinical picture of non-verbal disordered communication is a complex of predominantly bilateral and/or right hemisphere cortical deficits. Moreover, in B, insensitivity to pain, smells, noises and internal bodily feelings suggested a more general emotional anaesthesia and/or a deficient means of expression. It is possible that a limbic component might be involved, thus making affective appreciation also deficient.

Adult↗
PubMed2005

Perception and production of prosody by speakers with autism spectrum disorders.

Speakers with autism spectrum disorders (ASD) show difficulties in suprasegmental aspects of speech production, or prosody, those aspects of speech that accompany words and sentences and create what is commonly called "tone of voice." However, little is known about the perception of prosody, or about the specific aspects of prosodic production that result in the perception of "oddness." The present study examined the perception and production of a range of specific prosodic elements in an experimental protocol involving natural speech among speakers with ASD between 14 and 21 years of age, in comparison with a typical control group. Results revealed ceiling effects limiting interpretation of findings for some aspects of prosody. However, there were significant between-group differences in aspects of stress perception and production. The implications of these findings for understanding prosodic deficits is speakers with autism spectrum disorders, and for future research in this area, are discussed.

Adolescent↗
PubMed2006

Abnormal selective attention normalizes P3 amplitudes in PDD.

This paper studied whether abnormal P3 amplitudes in PDD are a corollary of abnormalities in ERP components related to selective attention in visual and auditory tasks. Furthermore, this study sought to clarify possible age differences in such abnormalities. Children with PDD showed smaller P3 amplitudes than controls, but no abnormalities in selective attention. Adolescents with PDD showed abnormal selective attention, as reflected by larger auditory Processing Negativity (PN) and visual N2b, but no P3 abnormalities. Dipole localizations revealed that the locations of PN generators in subjects with PDD differed from controls. It was concluded that the abnormalities in selective attention in adolescents with PDD have a normalizing effect on P3, and possibly act as a compensatory process.

Adolescent↗
PubMed1996

Perception, learning and identification studied with reversible suppression of cortical visual areas in monkeys.

We use cold to reversibly suppress cortical areas involved in visual perception, learning and retrieval and we found a localization of functions essential for performance of delayed match-to-sample (DMS) in anterior ventral temporal cortex, we call ventral TE (TEv). We also found a visual input for this area that is separate from the one going to the heart of inferotemporal cortex and suppressing this input also impairs performance of DMS. Suppressing the dorsal half of TE (TEd) disrupts retrieval of some, but not all complex images, and different images are disrupted in different animals. This variability within and between animals is extreme, with perfect performance on some complex images and below chance on others. We suggested that TEd represents some, but not all elements of the images. In attempting to discover what those elements might be, we found that TEd suppression disrupts the perception of small figures, but not the larger figures that they compose. We also found that it impaired the discrimination and matching of colors, without impairing the ability to detect and differentiate hues. We proposed that TEd represents the details and colors of things, but not global figures. Also, complex objects do not have a representation in one area, rather its representation involves the entire visual system, including TE with different elements of the image represented in different parts.

Animals↗
PubMed2004

Validation of a Developmental Neuropsychological Assessment (NEPSY) through comparison of neurological, scholastic concerns, and control groups.

Validity of the standard, 13 subtest A Developmental Neuropsychological Assessment (NEPSY) was investigated by comparing scores for 30 children with neurological conditions, 35 children with scholastic concerns, and 39 controls. Overall differences were found among the groups with and without controlling for IQ (Lambda = .60, Lambda = .001; Lambda = .70, P < .001). Four of five NEPSY domain scores differed among the three groups. Language and Sensorimotor domain score differences were found even when IQ was controlled, and group status accounted for substantial variance in these domain scores. Regarding specific tasks, Phonological Processing and Fingertip Tapping were among the subtests that varied the most between groups, especially when children with scholastic concerns were compared with controls. Findings offer preliminary support for the validity of several NEPSY indexes.

Achievement↗