Biomedical subjects

R F Asarnow

Publications and source records attributed to R F Asarnow.

At least 37 records · Page 2Linked to original sources

PubMed1997

Event-related potential correlates of linguistic information processing in schizophrenics.

Event-related potentials (ERPs) were recorded from adult schizophrenics and age- and education-matched normal controls during performance of an idiom recognition task involving judgments of the meaningfulness of idiomatic, literal, and nonsense phrases. Schizophrenics produced more errors and had prolonged reaction times while attempting to correctly differentiate meaningful from meaningless phrases. An ERP correlate of that deficit was a larger than normal N400 to idioms and literals, with no difference in N400 amplitude to nonsense phrases. This result was interpreted as evidence that the influence of the linguistic context provided by the first word of two-word idiomatic and literal phrases is reduced in schizophrenia. Schizophrenics also showed reduced amplitude P300.

Adult↗

PubMed1997

Pupillary responses index overload of working memory resources in schizophrenia.

The authors examined the hypothesis that schizophrenia patients have reduced availability of working memory resources by using pupillary responses as an index of resource overload. Pupillary responses were recorded during a verbal working memory task (digit recall) in 24 schizophrenia patients and 32 normal controls. Pupil size increased with increased processing load (digit-span length) but changed little or declined when processing demands exceeded available resources (overload). The schizophrenia patients showed impaired digit recall and abnormally small pupillary responses during digit presentation only in the higher processing load conditions, but they showed abnormally small pupillary responses during digit retrieval in all processing load conditions. The results suggest reduced availability of slave store and central executive working memory resources in schizophrenia. This study serves as an example of how pupillography methods can be used to test current hypotheses regarding overload of cognitive capacities in schizophrenia patients.

Adult↗

PubMed1997

Developmental outcomes in children receiving resection surgery for medically intractable infantile spasms.

Two-year postsurgical developmental outcomes were assessed in 24 children with infantile spasms who underwent resective surgery. The mean age of onset of infantile spasms was 12.0 weeks and the mean age at surgery was 20.8 months. Developmental outcomes were assessed using the Vineland Adaptive Behavior Scales (VABS). There was a significant increase in developmental level at 2 years postsurgery compared with presurgical levels. At 2 years postsurgery only one of the children in this series was severely retarded. The developmental outcomes of patients in the series were better than those in prior studies of symptomatic patients receiving medical treatment for infantile spasms. It is surprising that the children in the UCLA series frequently had developmental outcomes equal to and sometimes superior to other groups of children with infantile spasms, since all the UCLA patients were symptomatic, had neurologic deficits and had failed to respond to adrenocorticotrophic hormone (ACTH) and antiepileptic drugs. The 2-year postsurgery developmental outcomes were best for the children who received surgery when they were relatively young and who had the highest level of developmental attainments presurgically.

Activities of Daily Living↗

PubMed1997

Depressive symptoms in the early course of schizophrenia: relationship to familial psychiatric illness.

OBJECTIVE: This study examined the relation between the presence of depressive symptoms in schizophrenic patients with a recent first psychotic episode and affective disorders among their relatives. METHOD: Data on depressive symptoms in 70 patients with schizophrenia diagnosed according to the DSM-III-R criteria, who had had a recent first psychotic episode, and psychiatric diagnostic information on 293 of their first-degree and 674 of their second-degree relatives were collected. Depressive symptoms in the schizophrenic probands were examined at the index psychotic episode (at study entry) and systematically over a 1-year follow-through period. The majority of first-degree family members were interviewed in person with the use of semistructured diagnostic interviews. RESULTS: The linear regression findings confirmed the hypothesis that depressive symptoms in the early course of schizophrenia are associated with a family history of unipolar affective illness. CONCLUSIONS: Because depression in the patients was associated with a family history of depression, this suggests that depression in schizophrenia is not solely either a reaction to having had a psychotic episode or part of the recovery process. The findings are consistent with a model in which a familial genetic liability to affective disorder, when present, is viewed a s exerting a modifying influence on the patient's schizophrenic illness to increase expression of depressive symptoms.

Adolescent↗

PubMed1996

Continuous-processing--related event-related potentials in children with attention deficit hyperactivity disorder.

Visual information processing in children with attention deficit hyperactivity disorder (ADHD) was studied using event-related potentials recorded during two versions of the Continuous Performance Task (CPT). ADHD children made more errors, and had longer reaction times than normal children on both the single- and dual-target CPT. Event-related potential waveforms were normal in the ADHD children with reference to early processing stages, i.e., contingent negative variation, P1-N1 laterality, and processing negativities, suggesting that ADHD children did not differ in their level of preparedness or their ability to mobilize resources for target identification and categorization. With respect to later processing, P3 amplitude was reduced in the ADHD group, whereas P3 latency was longer than normal. ADHD children had a diminished late frontal negative component, suggestive of reduced involvement in postdecisional processing.

Adolescent↗

PubMed1996

Span of apprehension deficits in older outpatients with schizophrenia.

Performance on the span of apprehension task, a well-studied information processing task in schizophrenia research, was examined in 11 schizophrenia patients and 11 normal comparison participants, all over the age of 45 years. Subjects detected "T' and "F' targets in briefly-flashed arrays of 1, 6, and 12 letters on the span task. Consistent with previously reported findings in younger schizophrenia patients, the older patients detected significantly fewer targets in the larger (12-letter), but not smaller (1-, or 6-letter), arrays. The older schizophrenia patients also showed significantly slower reaction times in all array-size conditions. Neither age of onset nor duration of illness was significantly correlated with span task performance. The characteristic span of apprehension task deficit found in the older schizophrenia patients suggests that late-life schizophrenia shares a common cognitive impairment with childhood and young adulthood schizophrenia, and provides supportive evidence for a possible stable vulnerability trait deficit in schizophrenia that is independent of age of onset and duration of illness.

Age Factors↗

PubMed1996

Display visual angle and attentional scanpaths on the span of apprehension task in schizophrenia.

The effect of display visual angle on span of apprehension (SOA) task performance was investigated in patients with schizophrenia and nonpsychiatric individuals. Narrow and wide visual-angle presentations of 3- and 10-letter arrays were compared. Detection rates were significantly higher with narrow than wide visual angle for nonpsychiatric individuals; the performance of those with schizophrenia was stable across visual-angle conditions. Patients with schizophrenia were best discriminated from nonpsychiatric individuals in the narrow-angle, 10-letter condition. Scanpath analyses, which were based on the pattern of detection rates across different target quadrant locations, suggested that the patients with schizophrenia used a similar number and path of covert scan moves as did the controls. Hypotheses are discussed regarding which of the multiple cognitive processes tapped by the SOA task may be impaired in schizophrenia.

Adult↗

PubMed1996

Pupillary responses index cognitive resource limitations.

Cognitive task-evoked pupillary responses reliably index information-processing loads. However, previous studies have reported inconsistent findings regarding the nature of the pupillary response when processing demands approach or exceed available processing resources. This condition was examined in 22 normal undergraduates by using pupillometric recordings during a digit span recall task, with 5 (low load), 9 (moderate load), and 13 (excessive load) digits per string. Pupillary responses increased systematically with increased processing load (to-be-recalled digits) until the limit of available resources (memory capacity of 7 +/- 2 digits), when they reached asymptote and then declined with resource overload (> 9 digits). These findings suggest that pupillary responses increase systematically with increased processing demands that are below resource limits, change little during active processing at or near resource limits, and begin to decline when processing demands exceed available resources.

Adult↗

PubMed1995

Children with a schizophrenic disorder: neurobehavioral studies.

This paper summarizes retrospective and cross-sectional neurobehavioral studies of schizophrenic children. Retrospective studies of schizophrenic children reveal that during early childhood, prior to the first onset of schizophrenic symptoms, most schizophrenic children showed delays in language acquisition and/or impairments and delays in visual-motor coordination. These impairments appear to be developmental delays rather than fixed neurobehavioral impairments, because cross-sectional studies conducted when the children are at least 10 years of age, after the first onset of psychosis, fail to detect the same deficits. The results of behavioral, cognitive/neuropsychological studies as well as the study of event-related potentials measured during performance of cognitive tasks suggests that schizophrenic children suffer from limitations in processing resources. It is argued that the developmental delays observed in schizophrenic children represent the greater time it takes them to automate certain skills. The delay in automation may reflect their limited information-processing capacity.

Brain↗

PubMed1995

Children's color trails.

Color Trails for Children was developed in response to the need for instruments which minimize cultural bias in neuropsychological testing. The test, similar in format to Trail Making, was designed to provide an evaluation of speeded visuomotor tracking while minimizing the influence of language. The present research involves two exploratory studies which examine the relationship between Color Trails for Children and Trail Making, factors that may affect performance times, and discriminant validity. Results indicate that the tests appear to measure the same neuropsychological domains, and administration of Trail Making did not significantly alter performance times on Color Trails. Increasing age and IQ were related to quicker completion time for both tests. Females were found to complete Color Trails 2 and Trail Making Part B more quickly than males in this sample. Comparison between children diagnosed with learning disabilities, attention deficits, or mild neurological conditions and a preliminary standardization sample supported the discriminant validity of Color Traits to distinguish between normal controls and children with altered neuropsychological functioning. Comparison between clinical conditions indicated that Color Trails 2 was particularly sensitive in discriminating among the groups. Although further research is needed, results suggest that Color Trails has the potential to be an effective research and clinical tool in child neuropsychological assessment.

Journal Article↗

PubMed1994

Continuous-processing related ERPS in schizophrenic and normal children.

The continuous performance task (CPT) has proven to be sensitive to schizophrenic impairments. Multichannel event-related potential (ERP) data were recorded from schizophrenic and normal children during performance of easy and hard versions of the CPT. Schizophrenics produced fewer hits, more false alarms, and prolonged reaction times. Poor performance in schizophrenics was associated with four ERP abnormalities: (1) Schizophrenics did not exhibit the normal increase in amplitude of an early-onset, processing-related negativity from nontarget to target stimuli, suggesting a failure to appropriately allocate attentional resources to discriminative processing. (2) Although P3 amplitude to targets was not significantly smaller in schizophrenic children, the distribution of P3 amplitude between target and nontarget responses in the easy and hard versions of the CPT was abnormal, suggesting that schizophrenics differed in the strategic allocation of resources in later stages of CPT processing. (3) In all task conditions schizophrenics showed a parietal negative component with a latency of 400 msec seen in younger, but not older normal children, suggestive of maturational lag. (4) ERP data demonstrated absence of right-lateralized P1/N1 amplitude in schizophrenic children. Taken together these data indicate that at several stages of information processing, schizophrenics are deficient in the control and strategic allocation of processing resources.

Attention↗

PubMed1994

Persisting negative symptoms and information-processing deficits in schizophrenia: implications for subtyping.

To test the hypothesis that schizophrenic patients with persisting negative symptoms have stable information-processing impairments compared with schizophrenic patients without persisting negative symptoms, 20 chronic schizophrenic outpatients were trichotomously subgrouped on the basis of the level of negative symptoms that they displayed across multiple rating periods over a 1-year period. Brief Psychiatric Rating Scale assessments of negative symptoms were used to assign subjects into either an operationally defined persisting negative symptom (PNS), transient negative symptom (TNS), or no negative symptom (NNS) subgroup. The level and pattern of these subgroups' performance on a visual information-processing task, the Span of Apprehension Test (SPAN), were compared. Although the three groups did not differ statistically in level of SPAN performance during a drug-free baseline, the PNS group had significantly poorer SPAN performance than the other two groups at the 1-year followup assessment. The SPAN performance of the TNS and NNS groups improved while the SPAN performance of the PNS group did not improve over the 1-year followup period.

Adult↗

PubMed1994

Effects of attention training on information processing in schizophrenia.

This study evaluated the impact of a cognitive retraining intervention designed to enhance the attention skills of schizophrenia patients. The dependent variables included measures of perceptual sensitivity and sustained vigilance derived from a visual continuous performance test, as well as visual span of apprehension and world-list recall. Sixteen subjects received approximately 15 hours of repeated practice with computer-mediated vigilance tasks. Seventeen subjects were assigned to a no-treatment control group. All subjects were rated on measures of negative and positive symptoms before treatment. Despite improved performance on the training tasks, no significant changes on the outcome measures were observed following treatment. Thus, it is suggested that cognitive rehabilitation interventions with schizophrenia patients stress the teaching of behavioral strategies that bypass deficits, rather than remediating deficiencies in basic abilities, such as attention.

Adult↗

PubMed1994

Childhood-onset schizophrenia: editors' introduction.

Descriptions of various psychotic symptoms in children began to appear in the psychiatric literature at about the same time as descriptions of psychotic symptoms in adults. For example, Kraepelin estimated that at least 3.5 percent of his cases of dementia praecox had onsets before age 10. The construct of "childhood schizophrenia" initially emerged from attempts to classify a broad range of psychotic children. By the late 1940s and 1950s, the diagnosis of "childhood schizophrenia" was given to many disturbed children who today would be considered to have infantile autism and other developmental disabilities. In the early 1970s infantile autism and its variants was differentiated from schizophrenia of childhood onset. These changes were incorporated in DSM-III, which returned to the practice before 1930 of diagnosing schizophrenia in children using the same criteria as for adults, with minor allowances for differences in the manifestations of these symptoms during childhood. The studies presented in this issue of Schizophrenia Bulletin use DSM-III, DSM-III-R, or ICD-9 criteria for schizophrenia.

Adult↗

PubMed1994

Cognitive/neuropsychological studies of children with a schizophrenic disorder.

This article summarizes a series of cognitive/neuropsychological studies of children with schizophrenia. One set of studies, which surveyed a broad range of neuropsychological functions, revealed no evidence that children with schizophrenia are consistently impaired in sensory, perceptual, or language functions. Rather, the studies showed that children with schizophrenia performed poorly on tasks requiring sensory, perceptual, and language processing that made extensive demands on information-processing capacity. A second series of studies, which examined visual information processing by manipulating the processing demands of span of apprehension tasks, yielded similar findings. The key characteristic of tasks that elicit impaired performance in children with schizophrenia is that the task makes extensive demands on processing resources. This suggests that these children have limited information-processing capacity. Three hypotheses are proposed concerning the cognitive processes that are impaired in children with schizophrenia: (1) the cognitive processes that seem to be impaired in these children are part of a more general, hierarchically organized attention system; (2) the component processes of the system are subserved by different brain structures; and (3) the structures are part of a network that includes the frontal lobe and thalamus in interaction with the reticular activating system.

Adolescent↗

PubMed1994

Information-processing deficits across childhood- and adult-onset schizophrenia.

Event-related potentials were recorded for childhood- and adult-onset schizophrenia subjects performing the span of apprehension (Span) task, which is sensitive to vulnerability factors in schizophrenia. Subjects responded to the onset of the Span arrays in a reaction time condition and then responded differentially to the presence of one of two target letters in the Span condition. While neither the childhood- nor the adult-onset group exhibited abnormalities in preparatory contingent negative variation activity, both groups produced significantly less endogenous negative activity between 100 and 300 ms after Span stimulus onset than age-matched normals. This endogenous negative activity reflects attentional effort associated with serial search and stimulus identification. These results support the position that schizophrenia subjects are impaired in their ability to allocate adequate attentional resources for processing Span stimuli. Moreover, the similarity of this information-processing deficit in the two groups suggests that childhood- and adult-onset schizophrenia lie on a continuum in this regard.

Adolescent↗

PubMed1994

Reduced attention-related negative potentials in schizophrenic adults.

Event-related potentials were recorded from outpatient adult schizophrenics receiving maintenance doses of neuroleptics and from normal control subjects during performance of a reaction time task and a complex visual discrimination task, the Span of Apprehension. Difference potentials were computed to isolate endogenous activity associated with the processing demands of the Span task. Schizophrenics produce significantly less early endogenous negative activity than do normal subjects. This processing-related negativity reflects pattern matching activity to an attentional trace during the serial scan of the visual icon. We previously reported an identical reduction in processing-related negativity in childhood-onset schizophrenia, suggesting that this deficit is age independent. Both frontal contingent negative variation and an early frontal P3 were larger in the schizophrenics than in normal subjects, suggesting an inappropriate mobilization of nonspecific attentional resources. A later posterior P3 was significantly smaller in schizophrenics than in normal subjects.

Adult↗

PubMed1993

Event-related potentials in high-functioning adult autistics: linguistic and nonlinguistic visual information processing tasks.

Event-related potentials (ERPs) were recorded from high-functioning adult autistics and age- and IQ-matched normal controls during performance of two non-linguistic information processing tasks, the Continuous Performance Task (CPT) and Span of Apprehension (SPAN), and an Idiom Recognition Task (IRT) involving idiomatic, literal and nonsense phrases. The autistics exhibited behavioral deficits only when attempting to identify idiomatic phrases. The ERP correlate of that deficit was greatly reduced N400 to idioms. In addition, autistics produced larger N1 amplitudes in all tasks, and larger P3s in the IRT and CPT.

Adolescent↗