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Biomedical subjects

R F Asarnow

Publications and source records attributed to R F Asarnow.

At least 55 records · Page 3Linked to original sources
PubMed1993

Preliminary associations between motor procedural learning, basal ganglia T2 relaxation times, and tardive dyskinesia in schizophrenia.

The hypothesis that the caudate nucleus is involved in the pathophysiology of tardive dyskinesia (TD) in schizophrenia was investigated by examining motor procedural learning on the pursuit rotor task and basal ganglia T2 relaxation times (T2) determined using magnetic resonance imaging (MRI). Increased severity of TD was associated with shortened caudate T2 and decreased motor learning. Motor-learning scores of schizophrenic patients with and without TD did not differ significantly from those of normal control subjects, but motor learning in the schizophrenic patients correlated with caudate T2. The results suggest that a corticocaudate system subserves motor procedural learning and provide converging evidence from neuropsychological and MRI measures suggesting caudate involvement in TD.

Adult↗
PubMed1992

Span of apprehension in schizophrenic patients as a function of distractor masking and laterality.

Twenty schizophrenic patients, 10 depressed control patients, and 20 normal control subjects were compared in a forced-choice, target-detection method for assessing the span of apprehension. The detection task required the subject to report which of 2 target letters was presented among 7 other (distractor) letters. Performance accuracy was examined as a function of target location and whether the distractor letters were masked after their presentation. The backward masking of the distractors improved target-detection accuracy of both control groups but reduced accuracy of the schizophrenic group. In addition, schizophrenics performed particularly poorly on targets located in the left half or lower half of the display. These results suggest that response to the masking of distractors may be a new index of attentional shortcoming in schizophrenia. Various theoretical explanations for the target location findings are also discussed.

Adult↗
PubMed1991

Reduced attention-related negative potentials in schizophrenic children.

ERPs were recorded from normal and schizophrenic children during performance of a reaction time task (RT) followed by a complex visual discrimination, the span of apprehension task (Span), sensitive to vulnerability factors in schizophrenia. Subjects responded rapidly to the onset of the visual arrays in the RT condition and differentially to the presence of 1 of 2 target letters in the Span condition. The EEG was recorded at 19 scalp sites and ERPs included activity 1 sec before through 1 sec after Span array onset. Difference potentials (Span-RT) were computed to remove unvarying exogenous activity, thus isolating endogenous activity associated with the processing demands of the Span task. When RT and Span task ERPs are compared, schizophrenic children produced a significantly smaller than normal increment in endogenous negative activity. This endogenous negativity differed in its topography and time course from the exogenous components (P1, N1 and P2), and most likely reflects attentional effort associated with serial search, pattern recognition and stimulus identification. We believe that the current results support the position that schizophrenics are impaired in their ability to allocate adequate attentional resources for the processing of the Span stimuli. It is important to note that this deficit is apparent quite early in discriminative processing.

Analysis of Variance↗
PubMed1991

Interrater reliability of the Structured Clinical Interview for DSM-III-R, Axis II: schizophrenia spectrum and affective spectrum disorders.

Three interviewers (second raters) blindly rated 15 audiotapes each of the Structured Clinical Interview for DSM-III-R, Axis II (SCID-II) administered to the first degree relatives of probands with either DSM-III-R schizophrenia, schizoaffective disorder, or bipolar disorder, for a total of 45 second ratings. Interrater reliability was determined using the intraclass correlation coefficient and ranged from 0.60 to 0.84. The previous studies of the reliability of structured interviews for diagnosing personality disorders are summarized and compared to the present findings. We conclude that the SCID-II can be reliably used to diagnose schizophrenia-spectrum and affective spectrum disorders in the first degree family members of probands with schizophrenic or bipolar affective disorders.

Affective Disorders, Psychotic↗
PubMed1991

Genetic factors for the span of apprehension test: a study of normal twins.

The Partial Report Span of Apprehension test has been found to detect cognitive deficits in some first degree relatives of schizophrenic patients. To assess the relative contribution of genetic vs. environmental factors on this measure, 19 monozygotic and 14 dizygotic female twin pairs, selected from a normal population, were tested on the Span of Apprehension test and an IQ test. Both Span of Apprehension test performance and IQ score had high heritabilities: 0.65 and 0.71, respectively. The mode of transmission for performance on the Span of Apprehension test appears to operate in a nonadditive manner. A multivariate behavioral-genetic model applied to the Span of Apprehension and IQ measures indicated that slightly less than half of the genetic effects important for the Span of Apprehension test are found in common with the genetic factors important for IQ. The phenotypic correlation between the Span of Apprehension and IQ measures can be attributed entirely to genetic factors. The influence of unique genetic components in the performance of the Span of Apprehension test in the general population heightens the promise of this measure as a genetic marker for schizophrenia.

Adult↗
PubMed1991

Controlled information processing resources and the development of automatic detection responses in schizophrenia.

The relation between resource limitations and the type of processing (automatic vs. controlled) on a multiple-frame search task (MFST) was examined in 15 schizophrenic and 15 normal control subjects. After 320 trials of consistently mapped practice, the patients' detection accuracy was normalized, and the effect of processing load (letter array size) on their detection accuracy was eliminated, which suggests automatization. Changes in load effects with practice could not be used as an index of automatization in control subjects, because of their unexpected lack of load effects at the beginning of practice. In a dual-task (MFST during auditory shadowing) condition after MFST practice, patients' MFST accuracy deteriorated nonsignificantly, and patients' shadowing declined significantly. The findings suggest schizophrenics have reduced available processing resources, but research is needed to determine whether this is due to abnormal automatization.

Adult↗
PubMed1991

Behavior problems and adaptive functioning in children with mild and severe closed head injury.

Assessed behavior problems and adaptive functioning in children with mild or severe closed head injuries, on average more than 2 years postaccident. To ensure that any problems detected in the present study were not merely preexisting problems, potential subjects were excluded if there was a history of preexisting CNS damage, significant developmental delay, or behavior problems. Children with severe head injuries had an excessive rate of behavior problems and impaired adaptive functioning. Children with mild head injuries also had an excessive rate of behavior problems (comparable to that of children with severe head injuries) but did not have impaired adaptive functioning. Results are discussed in terms of six alternative ways brain injury and behavior problems can be related functionally.

Activities of Daily Living↗
PubMed1990

Event-related potential correlates of impaired attention in schizophrenic children.

Electrophysiological correlates of focused attention were studied in 13 schizophrenic and 19 age- and gender-matched children. Subjects performed a version of the Continuous Performance Task (CPT) in which a target was designated as any digit from 0 through 9 occurring on two successive stimulus presentations. Signal digits were surrounded by distractor digits which varied in position, value, and number. Event-related potentials (ERPs) elicited by each stimulus of a target pair were recorded from midline and homologous parietal, temporal, and occipital electrode placements. Schizophrenic children made significantly more errors of omission and commission than normal children. The amplitude and time course of the intertrial CNV was the same for both groups. There was a circumscribed amplitude asymmetry, left smaller than right, for the P1/N1 and P2 measures which was greater in normal than in schizophrenic children. The P3 component was significantly larger to the second stimulus of the target pair than to the first for both groups, and larger for the normal than the schizophrenic children to both stimuli.

Arousal↗
PubMed1990

Information processing deficits of schizophrenic children with formal thought disorder.

The relations among formal thought disorder, the partial report span of apprehension task, the distractibility factor on the Wechsler Intelligence Scale for Children-Revised (WISC-R), and IQ scores were examined in 31 schizophrenic children, aged 7.4 to 12.5 years. The partial report span of apprehension scores of the schizophrenic children correlated significantly with their illogical thinking scores. Their scores on loose associations were significantly associated with the WISC-R distractibility factor score. The attention/information processing deficits that might underlie the clinical manifestations of illogical thinking and loose associations in childhood onset schizophrenia are discussed.

Attention↗
PubMed1988

Differential effect of low and conventional doses of fluphenazine on schizophrenic outpatients with good or poor information-processing abilities.

Thirty-six stabilized schizophrenic outpatients were randomly assigned to receive either 5 or 25 mg of fluphenazine decanoate biweekly and were followed up for two years. The best and worst outcomes were found in groups with good or poor information-processing abilities (as measured by a partial-report span-of-apprehension task) given the same 25-mg dose of fluphenazine decanoate. The 86% two-year survival rate of the patients with poor span performance was considerably better, while the 44% one-year and the 21% two-year survival rates of patients with good span performance were considerably lower than previously reported survival rates for schizophrenic patients receiving a conventional dose of fluphenazine. The significant correlations in a patient's span performance for periods up to one year were consistent with the hypothesis that this task taps processes associated with vulnerability to schizophrenic disorder.

Adult↗
PubMed1988

Autism and genetics. A decade of research.

The last ten years of research on the genetics of infantile autism were critically reviewed. Epidemiologic findings have shown that autism is a rare disorder with a prevalence of two to five per 10,000, a male-female ratio of 3:1, and an association with mental retardation (66% to 75% of autistic subjects have full-scale IQ scores [70]). Autism is familial, as reflected in an empiric sibling recurrence risk of 3% and pooled monozygotic and dizygotic concordance rates of 64% and 9%, respectively, which are much greater than the population prevalence of 0.02% to 0.05%. Genetic heterogeneity is pronounced with potential genetic subgroups, including autosomal recessive inheritance, X-linked inheritance, and sporadic chromosomal anomalies. Studies of subclinical markers in autism have elucidated potential markers at various levels of phenotypic expression from the DNA to the behavioral level. Linkage and cytogenetic studies point to two chromosome regions as putative markers, 9q34 and Xq27. Results of family studies support a putative biochemical marker, low levels of plasma dopamine-beta-hydroxylase, and a putative cognitive marker, ie, normal visuospatial but low verbal functioning, in autism. The frequency of minor physical anomalies and presence or absence of mental retardation are two dimensions of the physical and behavioral phenotype that may demark etiologically distinct subgroups. Genetic heterogeneity is offered as one explanation of the observed sex difference in the prevalence of autism. Directions for potentially fruitful research should be considered.

Adolescent↗
PubMed1988

Symptom development in childhood onset schizophrenia.

Symptom development from birth to 12 years of age was examined in 18 children who met DSM-III criteria for schizophrenia with onset before 10 years of age. Using a follow-back design, symptom development was rated at each of four age levels using a DSM-III Symptom Rating Scale and the Achenbach Child Behavior Checklist. Results revealed a gradual developmental unfolding of a broad spectrum of symptoms affecting social, cognitive, sensory and motor functioning and beginning many years before the appearance of schizophrenic symptoms--usually in early infancy. Prior to 6 years of age, severe language deficits and motor development problems were each found in 72% of the sample and symptoms of infantile autism were found in 39% of the sample. Onset of schizophrenia occurred at an earlier age for children with a history of autistic symptoms during infancy than for other children in the sample. Schizophrenia as defined by DSM-III was entirely absent before 6 years of age.

Autistic Disorder↗
PubMed1987

A comparison of cognitive/neuropsychological impairments of nonretarded autistic and schizophrenic children.

The performance of children meeting DSM-III criteria for schizophrenic disorder and infantile autism and of normal children (ages 7 years 10 months to 14 years 4 months) was compared on the Wisconsin Card Sorting Test, Rey's Tangled Line Test, Benton Judgment of Line Orientation, Digit Symbol Substitution Test, and Peabody Picture Vocabulary Test. The mean performance IQ of the schizophrenic and autistic children was equal and in the normal range. The normal children were of average intelligence as estimated by the PPVT. As compared to normal children, both autistic and schizophrenic children were impaired on the DSST and RTLT. The autistic children had significantly lower scores on the PPVT than schizophrenic and normal children. The schizophrenic children made significantly more perseverative responses on the WCST than did normal children. They significantly increased their nonperseverative errors on the second half of the WCST, after having been taught the correct sorting principles. It is argued that in schizophrenia a core deficit in momentary processing capacity underlies the above performance pattern. In contrast, in autism the core cognitive deficit involves an inability to use language to regulate and control ongoing behavior.

Adolescent↗
PubMed1987

Patterns of intellectual functioning in non-retarded autistic and schizophrenic children.

The WISC-R factor scores of non-retarded children meeting DSM III criteria for autism and schizophrenia were compared. The scores of the schizophrenic children on factor 3 were significantly lower than those of the autistic children, below the range of normal children, and significantly lower than the scores they obtained on the verbal comprehension and perceptual organization factors. The autistic children scored in the superior range on the block design subtest and did not show gross impairments in language function as indexed by scores on the verbal comprehension factor. The only subtest autistic children were impaired on was the comprehension subtest.

Attention↗