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PubMed2003

Visual backward-masking deficits in schizophrenia: relationship to visual pathway function and symptomatology.

Patients with schizophrenia have information processing deficits which can be measured using visual backward-masking (VBM) tasks. There are two types of visual pathways: transient and sustained. The former is more sensitive to low spatial frequency (LSF) and the latter to high spatial frequency (HSF) stimuli. It has been hypothesized that the VBM deficit in schizophrenia is due to an overactive transient channel response to the mask. To examine this hypothesis, patients with schizophrenia and comparison volunteers were tested on a traditional backward-masking task as well as on tasks that altered the mask to bias stimulation toward transient (LSF) or sustained (HSF) channels. Medication effects and relationship to symptomatology were also examined. Patients with schizophrenia showed a significant deficit on the traditional backward-masking task and were also significantly impaired on the LSF- and HSF-masking tasks, though a differential deficit was not found on the latter two tasks. A U-shaped function, indicative of masking by interruption, was found on the LSF- and HSF-masking tasks. Masking performance was not altered when the same patients were tested on and off medication, and performance was related to positive and negative symptoms. In conclusion, the finding of a deficit in patients with schizophrenia on tasks producing a U-shaped function suggests that an aberrant transient response to the mask is producing increased interruption of the sustained response to the target.

Adult↗
PubMed2003

Social perception and early visual processing in schizophrenia.

Persons with schizophrenia experience deficits in social cognition-the cognitive processes involved in how people perceive and interpret information about themselves, others, and social situations. These deficits may be related to the neurocognitive impairments often experienced by persons with schizophrenia. Our primary objective was to examine associations between social perception and early visual processing in schizophrenia. Our secondary objective was to examine whether outpatients with schizophrenia and healthy persons differ in social perception. Forty outpatients with schizophrenia and 30 healthy persons completed a measure of social perception (the Half-Profile of Nonverbal Sensitivity), visual masking procedures, and ratings of positive and negative symptoms. Within patients, performance on visual masking procedures was related to performance on the Half-Profile of Nonverbal Sensitivity. Patients with schizophrenia and the healthy persons differed significantly in their performance on the Half-Profile of Nonverbal Sensitivity, but this difference became nonsignificant when education was a covariate. These findings suggest that social perception in schizophrenia is related to very early aspects of visual processing.

Adult↗
PubMed2002

Comparing tests of tactile sensibility: aspects relevant to testing children with spastic hemiplegia.

Children with hemiplegic cerebral palsy (OP) commonly exhibit tactile sensory deficiencies in their hands in addition to their motor problems. The aim of this study was to compare and evaluate the usefulness of some common tests of tactile sensibility for use with children with hemiplegic CP. Twenty-five children with hemiplegia aged between 5 and 18 years, and 19 control individuals participated. All children were examined with Semmes-Weinstein monofilaments, two-point discrimination (2PD), stereognosis of familiar objects, stereognosis of forms, and functional sensibility. Dexterity, spasticity, and bimanual task performance were also assessed. Results from the different sensory tests deviated greatly. We found three tests to be useful: 2PD of 3 mm spacing, which was the most sensitive test, stereognosis of familiar objects, and functional sensibility assessed through the Pick-up test (comparing performance with and without the influence of vision). Stereognosis of forms and threshold values of touch (Semmes-Weinstein monofilaments) are seemingly less useful tests for children with CNS impairments. Deficient sensibility was strongly related to dexterity. Aspects concerning the testing methodology are discussed.

Adolescent↗
PubMed2004

Interhemispheric transfer in high-functioning children and adolescents with autism spectrum disorders: a controlled pilot study.

Autism is a neurodevelopmental disorder with strong genetic influences. Clinical experience and limited empirical evidence support the view that autism may be associated with aberrant interhemispheric information transfer. This empirical controlled study examined whether, at neuropsychological testing, children with autism showed problems with interhemispheric information transfer. The study included auditory, visual, and motor measures covering information transfer within, as well as across, modalities. Thirty children (24 males, 6 females; mean age 12 years 8 months, SD 2 years 8 months; range 9 years 5 months to 17 years 5 months) without learning disability but with autism spectrum disorders were compared with 30 children from a mainstream school matched for age, sex, and IQ>75. Children with autism spectrum disorder performed significantly worse than the comparison group on most of the tests (p=0.02 for auditory perception and attention, p=0.005 for visual perception, p=0.0001 for motor control, p=0.04 for tactile perception). Results support the notion that aberrant interhemispheric transfer may be involved in the pathogenesis or clinical course of autism. The findings were not accounted for by lower IQ in the group with autism.

Adolescent↗
PubMed2004

Neurocognitive profiles in Salla disease.

Salla disease, a free sialic acid storage disorder, is one of the 36 currently known disorders in Finland that form the Finnish disease heritage. Salla disease leads to learning disability* with a wide clinical variation. Two main categories of the disease have been classified: a conventional subtype and a severe subtype with more severe defects. We present detailed neurocognitive profiles of 41 Finnish patients with Salla disease (19 females, 22 males; age range 11mo to 63y, median 19y). The neurocognitive development of patients with Salla disease was assessed by psychological and neuropsychological testing. All patients were also examined by a paediatric neurologist and a speech therapist. The characteristic cognitive profile consisted of a lower non-verbal performance (mean developmental age 13mo) compared with linguistic skills (mean developmental age 17mo). In particular, spatial and visual-constructive impairments were typical of these patients. Tactile and visual discrimination of forms was poor. Tasks demanding hand-eye coordination, maintenance of visual attention, and those requiring short-term visual memory and executive skills were performed better. Receptive language skills were notably better compared with expressive speech. The patients' interactive and non-verbal communication skills were quite strong. Another typical pattern with Salla disease was severe motor disability. After the second decade of life, the decline in these skills was more pronounced than patients' cognitive deterioration. Our results indicate that even though there is a considerable variation in the clinical findings of patients with Salla disease, the characteristic neurocognitive profile of the disease can be outlined.

Adolescent↗
PubMed2007

Nature of motor imitation problems in school-aged males with autism: how congruent are the error types?

This case-comparison study explores the underlying mechanisms of imitation problems in school-aged males with autism. Analysis of congruent error types in their imitation performance was made and compared with appropriate comparisons. Fifty-five males (eight low-functioning with autism: mean age 6y 2mo [SD 7.6mo]; 13 low-functioning with learning disabilities: mean age 6y 3mo [SD 2.8mo]; 17 high-functioning with autism: mean age 8y 9mo [SD 11mo]; and 17 typically developing: mean age 8y 8mo [SD 11.6mo]) were assessed on 18 single gestures and six sequences of hand postures. Imitation performance was videotaped for blind scoring on 21 possible errors by two independent observers. Results revealed that in both groups with autism, imitation required far more effort (more attempts) than in the comparison groups and was less precise (more spatial errors). Typical for low-functioning participants with autism was their less mature imaginary grip in transitive gestures. Typical for high-functioning participants with autism was their preference for immature mirror-image imitations. These observations support the assumption that the underlying mechanisms in motor imitation problems are linked more to the action production system and less to the action conceptual system or to behavioural problems. We postulate that the action production system is delayed rather than deficient.

Autistic Disorder↗
PubMed1999

Motor coordination and kinaesthesis in boys with attention deficit-hyperactivity disorder.

In the current study, movement ability and underlying kinaesthetic processes of boys with attention deficit-hyperactivity disorder (ADHD) were compared with a group of control children. Two groups of 16 boys with either predominantly inattentive subtype ADHD (ADHD-PI) or combined subtype ADHD (ADHD-C) were compared with 16 control boys matched on age and verbal IQ. The findings demonstrated that the children with ADHD had significantly poorer movement ability than the control children. A high percentage of children with ADHD displayed movement difficulties consistent with developmental coordination disorder. In addition, the current study found that the type and degree of movement difficulty differed between subtypes. Children with ADHD-PI had significantly poorer fine motor skill while children with ADHD-C were found to experience significantly greater difficulty with gross motor skill. The severity of the children's inattentive symptomatology was found to be a significant predictor of motor coordination difficulties. Kinaesthetic sensitivity was not found to differ significantly between the groups.

Attention Deficit Disorder with Hyperactivity↗
PubMed1975

Influence of psychiatric training, medical qualification, and paramedical training on the rating of abnormal behaviour.

The psychiatric ratings, using the In-Patient Multi-dimensional Psychiatric Scale, of (1) a group of over 200 psychiatrists from the British Isles, (2) third year psychology students, (3) trainee sister tutors, (4) general practitioners attending a postgraduate course in psychiatry, and (5) a group of new registrars at the Maudsley Hospital, were compared. The first hypothesis, that, whereas the non-psychiatrists would rate similar levels of symptoms, the psychiatrists would tend to rate lower than other professional groups, was upheld. The second, that the pattern or profile of symptoms as shown by the IMPS syndromes would differ little between the groups, was also upheld. The third hypothesis, that because of their special training in the recognition of synptoms, psychiatrists would tend to show greater intra-group agreement on the levels of symptoms that the other groups, was not upheld. Some possible reasons for the findings are discussed. The importance for a screening schedule, designed to be used by non-psychiatrists for the detection of psychiatric illness, of the finding that non-psychiatrists rate higher levels of symptoms than psychiatrists, is also discussed.

Adult↗
PubMed2005

Strategy implementation in obsessive-compulsive disorder and trichotillomania.

BACKGROUND: The use of strategies to aid performance when undertaking neuropsychological tasks is dependent on intact fronto-striatal circuitry, and growing evidence suggests impaired spontaneous use of strategies in patients with obsessive-compulsive disorder (OCD). However, studies to date have not examined the effects of strategy training on task performance in OCD or in trichotillomania (compulsive hair-pulling, a condition that has been argued to share overlap with OCD in terms of phenomenology and co-morbidity). METHOD: The ability to generate novel visuospatial sequences using a computer interface was examined before and after undertaking optimal strategy training in 20 OCD patients, 17 trichotillomania patients, and 20 controls (matched for age, education, and IQ). RESULTS: OCD patients failed to improve ability to generate novel sequences above baseline despite successfully completing strategy training to the same extent as other groups. In contrast, performance of trichotillomania patients improved significantly after training to the same extent as controls. Groups did not differ on memory span, trial-by-trial action monitoring, or ability to generate novel visuospatial sequences prior to strategy training. CONCLUSIONS: Strategy implementation deficits, suggestive of cognitive inflexibility and fronto-striatal dysfunction, appear integral to the neurocognitive profile of OCD but not trichotillomania. Future research should investigate cognitive flexibility in obsessive-compulsive spectrum disorders using a variety of paradigms, and clarify the contribution of specific neural structures and transmitter systems to deficits reported.

Adult↗
PubMed1993

Cerebellar dysfunction of movement and perception.

This review describes some characteristics of patients with cerebellar lesions, including limb movements, changes in motor planning and disturbances in time-dependent perception. The delay in movement initiation can be explained by a delay in onset of movement-related discharge of neurons in motor cortex. Disorders of movement termination (hypermetria) are accompanied by asymmetric velocity profiles and by prolonged agonist and delayed antagonist EMG activity necessary to brake the movement. During complex movements in three-dimensional space, the cerebellum contributes to timing between single components of a movement, scales the size of muscular action, and coordinates the sequence of agonists and antagonists. The basic structure of motor programs is not generated exclusively within the cerebellum and patients with cerebellar lesions can use precuing information to improve their motor performance. Time-dependent perception in the auditory and visual domains are disturbed in patients with cerebellar lesions.

Cerebellar Diseases↗
PubMed2000

Neuropsychological and neuropathological sequelae of cerebral anoxia: a critical review.

Fifty-eight studies of the neuropathological and neuropsychological outcomes of cerebral anoxia were reviewed. Neuropathological reports were examined for the variety, extent, and specificity of lesions resulting from an anoxic event. While most attention has focused on damage to the hippocampus following anoxic brain injury, the review indicated that watershed cerebral cortex and the basal ganglia were both more frequently damaged than the hippocampus. The hippocampus was the sole affected structure in only 18% of reported cases. Neurological, neuropsychological and psychiatric studies were analyzed. Of 67 individual case reports, a memory disturbance was documented in 36 (54%), but a memory disturbance without report of additional cognitive deficits occurred in only 13 (19.4%). Changes in personality and behavior were noted in 31 (46.2%). Visuospatial or, less frequently, visual recognition problems were noted in 21 individual cases (31.3%) reviewed. Memory deficits were found in all 14 group studies reviewed, while in 9 papers changes in behavior or personality were also documented. Six studies also reported visuospatial deficits. Careful reading of the literature reveals a range of cognitive and behavioral changes that reflect very well the neuropathological outcomes of anoxic episodes.

Brain↗
PubMed2003

Motor adaptation in children with myelomeningocele: comparison to children with ADHD and healthy siblings.

Myelomeningocele is a common developmental malformation of the central nervous system that usually results in motor deficits. Previous studies of myelomeningocele have not examined motor adaptation, which involves changes in the control of movements that occur as a result of repeated task exposure but do not depend on conscious recall of the exposure. We studied motor adaptation in 17 children with myelomeningocele and shunted hydrocephalus, 19 children with attention deficit/hyperactivity disorder (ADHD), and 20 healthy siblings. All children were 8 to 15 years of age. They were administered 2 measures of motor adaptation known to be sensitive to subcortical abnormalities in adult neurological disorders. One task assessed the biasing in weight judgments that occurs after exposure to heavy versus light weights, and the other assessed the adaptation in reaching movements that occurs when vision is laterally displaced by prisms. Contrary to expectations, the groups did not differ in motor adaptation. Children in all 3 groups displayed significant biasing in their weight judgments and improvement in the accuracy of pointing during prism adaptation trials. Performance on the 2 motor adaptation tasks was not related to age or IQ. Weight biasing was positively related to a measure of response disinhibition. The findings suggest that myelomeningocele does not result in global impairment of motor skills, but instead in a profile of intact and impaired motor functions that potentially may be decomposed in accordance with the neuroscience of motor skills.

Adaptation, Physiological↗
PubMed2000

Interventions to facilitate auditory, visual, and motor integration in autism: a review of the evidence.

Evidence is reviewed on the prevalence of sensory and motor abnormalities in autism and the effectiveness of three interventions designed to address such abnormalities--sensory integration therapy, traditional occupational therapy, and auditory integration training. Although sensory processing and motor abnormalities are neither universal nor specific to autism, the prevalence of such abnormalities in autism is relatively high. There is, however, little controlled research on the effectiveness of interventions designed to address these abnormalities. Four objective outcome studies of sensory integration therapy were identified. These were of such small scale that no firm conclusions regarding efficacy could be made. No empirical studies of traditional occupational therapy in autism were found. Five studies of auditory integration training were found. Results of these studies provided no, or at best equivocal, support for the use of auditory integration training in autism.

Autistic Disorder↗
PubMed2003

Listening comprehension and working memory are impaired in attention-deficit hyperactivity disorder irrespective of language impairment.

This study investigated listening comprehension and working memory abilities in children with attention-deficit hyperactivity disorder (ADHD), presenting with and without language impairments (LI). A 4-group design classified a community sample (n = 77) of boys aged 9-12 into ADHD, ADHD + LI, LI, and Normal groups. Children completed tests of basic language and cognitive skills, verbal and spatial working memory, and passage-level listening comprehension. Multivariate analyses and post hoc comparisons indicated that ADHD children who did not have co-occurring LI comprehended factual information from spoken passages as well as normal children, but were poorer at comprehending inferences and monitoring comprehension of instructions. ADHD children did not differ from normal children in verbal span, but showed significantly poorer verbal working memory, spatial span, and spatial working memory. The ADHD + LI and LI groups were most impaired in listening comprehension and working memory performance, but did not differ from each other. Listening comprehension skills were significantly correlated with both verbal and spatial working memory, and parent-teacher ratings of inattention and hyperactivity/impulsivity. Findings that children with ADHD but no LI showed subtle higher-level listening comprehension deficits have implications for both current diagnostic practices and conceptualizations of ADHD.

Attention Deficit Disorder with Hyperactivity↗
PubMed2001

Working memory in schizophrenia and mania: correlation with symptoms during the acute and subacute phases.

OBJECTIVE: The aims of this study were to examine working memory in the acute subacute phase of schizophrenia and mania and to examine correlations between working memory and specific symptom domains. METHOD: Visuospatial working memory and symptom profiles were assessed in three groups (schizophrenia group, n= 19; mania, n= 12; controls, n= 19) on two occasions separated by 4 weeks. RESULTS: Both patient groups had significant deficits on working memory compared to the well controls and the schizophrenia and mania groups were equally impaired. All groups showed equivalent improvement over time. In the patient groups, impaired working memory was significantly correlated with the presence of both negative symptoms and positive thought disorder. CONCLUSION: Impaired working memory is found in both schizophrenia and mania during the acute subacute phases. Further research is required in order to clarify the neurocognitive mechanisms linking impaired working memory with both negative symptoms and positive thought disorder.

Acute Disease↗
PubMed1994

Determinants of repetition blindness.

Repetition blindness (RB) for letters presented in rapid serial visual presentation (RSVP) was shown to be highly dependent on absolute stimulus presentation rate (Experiment 1) and on the duration of the 2nd occurrence (C2) but not the 1st occurrence (C1) of the repeated item (Experiment 2). In Experiments 3-6, RB was strongly affected by C1-C2 interstimulus interval but not by response requirements or total memory load. In Experiment 7, sensitivity for detection of the 2nd vowel in an RSVP sequence of consonants was lower when it was identical to the 1st vowel (mean d' = .40) than when it was different (mean d' = .70). It is argued that RB is not due to (a) temporal overlap of C1 and C2 recognition, (b) forgetting of C2, (c) item-specific output interference, (d) response bias, or (e) guessing strategies; rather, RB arises because of the failure to bind recognized types to individuated tokens.

Adult↗