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Biomedical subjects

B E Wexler

Publications and source records attributed to B E Wexler.

At least 37 records · Page 2Linked to original sources
PubMed1996

A direct observational measure of whole body turning bias.

The directional preference for spontaneous turning in humans has previously been documented using an electronic device (rotometer). We used a simple, inexpensive, and well-controlled test of turning behaviour in 41 adults with no psychiatric diagnoses. In this test, the direction in which subjects turned is recorded as they complete each one of what they think is a series of evaluations of gait, in a room symmetrically spacious and free of distracters. A substantial majority of our right-handed subjects (N = 27) showed a significant leftward turning bias, while non-right handed group (N = 14) did not show this bias. Test-retest reliability for this measure in 17 individuals tested twice at different times was high (rho = 0.73).

Adult↗
PubMed1995

Behavioral laterality in individuals with Gilles de la Tourette's syndrome and basal ganglia alterations: a preliminary report.

This study aims to investigate whether abnormalities in structural basal ganglia asymmetries in Tourette's syndrome (GTS) have functional significance. Eleven adult GTS patients and 11 normal controls who had participated in the previous MRI study where GTS patients lacked the normal left-greater-than-right (L > R) lenticular asymmetry were re-recruited. They were administered a battery of lateralizing neuropsychological tasks believed to require intact basal ganglia function. GTS subjects lacked normal functional asymmetries on these measures, as predicted. The neuropsychological measures also accounted for a significant portion of the variance in the severity of tic symptoms. These findings suggest that GTS subjects who lack normal basal ganglia structural asymmetries also lack normal functional asymmetries on related neuropsychological measures.

Adult↗
PubMed1995

Functional significance of individual variations in callosal area.

We considered the hypothesis that the richness of callosal interhemispheric connections has a role in determining the degree of behavioural laterality and time-sharing ability in dual-task performance. Behavioural laterality as measured by dichotic word listening, line bisection and turning bias tests correlated inversely with the midsagittal cross-sectional area of the corpus callosum, as seen on MRI. The amount of dual task interference was strongly inversely correlated with the callosal area in both within-hemisphere and between-hemispheres conditions. These relationships between normal variations in callosal area, and outcomes on tests both of laterally and time-sharing capacity in normal adults suggest that the corpus callosum assumes a cross-excitatory role when subjects perform these tasks.

Adult↗
PubMed1995

Abnormal laterality in schizophrenics and their parents.

Previous studies found that schizophrenics do not show the normal right ear-left hemisphere perceptual advantage on language-related dichotic tests of lateralized cerebral function. We report evidence of a similar abnormality in non-schizophrenic parents of schizophrenic patients. Perceptual asymmetry was first measured with a dichotic word test which had previously yielded differences between schizophrenics and controls. The parents (n = 18) demonstrated a lower right ear advantage (REA) than controls (n = 10) (p = 0.05), but performed similarly to their schizophrenic offspring (n = 10). The same subjects were given two additional tests. Neutral words were paired with words of a positive emotional valence in one test, and with words of a negative emotional valence in the other. On these two tests, the parents were more similar to the controls than to their offspring with the schizophrenics demonstrating a lower REA than their parents (p = 0.005) on the negative test. These results suggest that schizophrenics and their parents have similar abnormalities in hemispheric activation at baseline only, but when listening to words with negative emotional valence, only the schizophrenics demonstrate a further decrease in left hemispheric activation.

Adult↗
PubMed1994

Decreased perceptual sensitivity to emotion-evoking stimuli in depression.

We measured two aspects of emotional response in depressed patients, as a preliminary study of the potential usefulness of such measures for elucidating pathophysiological mechanisms. First we used electromyography to measure the automatic mimicry on an individual's own face of facial displays of emotion observed on the faces of others. Next we used the fused dichotic listening paradigm to measure selective perception of both positive and negative emotion-related words as opposed to neutral words. Patients failed to show the normal facial mimicry of both positive and negative facial displays, despite normal cognitive processing of the stimuli. They also heard significantly fewer positive and negative words on the dichotic tests than did healthy controls. This suggests that depressed patients are hyposensitive to emotion-related stimuli in general.

Adult↗
PubMed1994

Abnormalities in rapid, automatic aspects of attention in schizophrenia: blunted inhibition of return.

When a visual cue is presented at the same location but 100 ms prior to presentation of a visual stimulus, reaction time to the stimulus is decreased. However, in healthy subjects if the interval between the cue and the stimulus is between 500 and 1500 ms, reaction time is increased ('inhibition of return'). The present experiment compared inhibition of return in 11 medicated and clinically stable schizophrenic outpatients and 11 healthy control subjects screened by SADS-L. Healthy subjects responded faster to true cues than false cues when the interval between cue and stimulus was 100 ms, but responded equally fast in the two conditions with a 200 ms interval and responded faster to false than true cues at 700 and 1200 ms intervals. Schizophrenics, in contrast, responded faster to true than false cues at both 100 and 200 ms intervals and showed lower than normal advantages on false as compared to true cues at 700 and 1200 ms intervals (group x cue type x interval interaction p < 0.01). Thus while schizophrenics showed 'inhibition of return' it did not begin until greater than normal intervals between cue and stimulus and was blunted in magnitude. This suggests failure of inhibitory mechanisms that are important in very rapid and automatic aspects of normal attention.

Adult↗
PubMed1994

Affective reactivity of language in stable schizophrenic outpatients and their parents.

We assessed levels of communication disturbance by counting the frequency of unclear linguistic references in the speech of 10 stable schizophrenic outpatients, 18 of their "unaffected" parents, and 10 nonpsychiatric controls, in affectively negative versus affectively positive conditions. Patient and parent groups scored approximately equally on the reference performance measure in the positive condition, and significantly more poorly than controls. Patients' speech deteriorated significantly in the negative condition, while parents' and controls' speech did not. The degree to which patients' speech was reactive to negative affect corresponded to the severity of their core positive symptoms of delusions and hallucinations. Poor reference performance in parents predicted poor performance and a more severe history of positive symptoms in their patient offspring. These data support the hypothesis that poor reference performance represents a vulnerability marker for schizophrenia, and that affective reactivity of language symptoms is associated with an underlying positive schizophrenic process.

Adult↗
PubMed1994

Neuroleptic exposure following inpatient treatment of acute mania with lithium and neuroleptic.

The authors examined continued neuroleptic exposure following inpatient treatment of mania with neuroleptics and lithium through structured chart review of 40 consecutive patients. At discharge, patients were receiving a mean of 793 mg/day (SD = 695) chlorpromazine equivalents; 6 months later they were receiving a mean of 634 mg/day (SD = 684). This decrease was statistically significant, but the patients' ongoing neuroleptic exposure remained substantial.

Adult↗
PubMed1993

Effects of emotion on perceptual asymmetry in adolescent inpatients with attention-deficit hyperactivity disorder.

OBJECTIVE: The authors studied the hemispheric functioning of adolescents with attention-deficit hyperactivity disorder (ADHD) in relation to this group's response to positively toned emotional stimuli. METHOD: Dichotic word tests were used to measure perceptual asymmetry in 21 adolescent inpatients and 24 control subjects. Ten patients had ADHD; 11 did not. Subjects were tested under four emotional conditions by using combinations of neutral, positive, and negative words. RESULTS: the ADHD group had lower right ear advantage (REA) scores when presented with stimulus pairs containing positive words than when presented with pairs not containing positive words. By comparison, the non-ADHD patient group and the control group had higher REA scores under positive emotional conditions than under non-positive conditions. CONCLUSIONS: The abnormal response to positive emotional tone supports the reward system dysfunction hypothesis of ADHD and may also have implications for learning problems, behavioral difficulties, and disturbed interpersonal relationships in this population.

Adolescent↗
PubMed1993

Asymmetrical visual deprivation: a technique to differentially influence lateral hemispheric function.

This article describes a contact-lens method to sustain asymmetry in visual deprivation and the use of this method to test the general hypothesis that asymmetry in input deprivation can shift activation balance in the integrated brain, differentially influencing lateral hemispheric function. Effects of asymmetrical visual deprivation were as predicted on lateral asymmetry of EEG theta, producing more theta over the deprived hemisphere. Cross-modal influence of such visual deprivation was found in the perception of pleasantness of odors. An interaction was found between side of visual deprivation and performance on verbal reasoning and spatial orientation tasks. A line-bisection test of visual attention was not sensitive to the effects. Fatigue as rated on the Profile of Mood States was greatest when the left hemisphere was deprived.

Adolescent↗
PubMed1992

EEG and EMG responses to emotion-evoking stimuli processed without conscious awareness.

Dichotic stimulus pairs were constructed with one word that was emotionally neutral and another that evoked either negative or positive feelings. Temporal and spectral overlap between the members of each pair was so great that the two words fused into a single auditory percept. Subjects were consciously aware of hearing only one word from most pairs; sometimes the emotion-evoking word was heard consciously, other times the neutral word was heard consciously. Subjects were instructed to let their thoughts wander in response to the word they heard, during which time EEG alpha activity over left and right frontal regions, and muscle activity (EMG) in the corrugator ("frowning") and zygomatic ("smiling") regions were recorded. Both EEG and EMG provided evidence of emotion-specific responses to stimuli that were processed without conscious awareness. Moreover both suggested relatively greater right hemisphere activity with unconscious rather than conscious processing.

Adolescent↗
PubMed1992

Dichotic listening in monozygotic twins discordant and concordant for schizophrenia.

Emotional and neutral word versions of the fused rhymed words dichotic listening test were administered to members of 18 pairs of monozygotic twins discordant for schizophrenia, 7 pairs concordant for schizophrenia, and 7 pairs of normal twins. In the discordant group, affected twins had smaller right ear advantages than did their unaffected cotwins for neutral words. The difference was completely attenuated with the presentation of emotional words or in less powerful between-group comparisons that included twins concordant for schizophrenia and normal twins. It is unlikely that this finding reflects an abnormality in the lateralized representation of language, both because we did not find a correlation between handedness scores and dichotic listening scores and because emotional stimuli normalized results. The finding may reflect abnormalities in the allocation of attention for priming language centers in the left hemisphere. 'At risk' subjects, i.e., the unaffected members of the discordant pairs, did not differ significantly from normal monozygotic twins on measures of dichotic listening.

Adult↗
PubMed1992

The outpatient treatment of depression. Implications of outcome research for clinical practice.

Multiple studies have demonstrated that individual psychotherapy, pharmacotherapy, and the two in combination are all effective treatments for depressed outpatients. However, the implications of these data for clinical practice have been incompletely considered, and the often drawn mistaken conclusion is that they support routine treatment with psychotherapy and pharmacotherapy together. Analyses of treatment success rates, treatment failure rates, and treatment dropout rates indicate that combined treatment offers no advantage over treatment with psychotherapy alone and only modest advantage over treatment with pharmacotherapy alone. Routine use of combined treatment, therefore, exposes patients to unnecessary costs and side effects. The data suggest that psychotherapy alone should usually be the initial treatment.

Ambulatory Care↗
PubMed1991

Cerebral laterality, perception of emotion, and treatment response in obsessive-compulsive disorder.

Patients with obsessive-compulsive disorder (OCD) had lower right-ear advantages than healthy controls on five different language-related dichotic listening tests of cerebral laterality. This abnormality was more pronounced in patients with more severe illness. Stimulus pairs in one test consisted of one word with a positive emotional valence and one emotionally neutral word. Pairs in another test consisted of one negative and one neutral word. Patients with OCD tended to hear fewer emotion-related words than did healthy controls, a finding also noted in depressed patients. Moreover, OCD patients who responded to treatment with serotonin reuptake inhibitors heard fewer emotion-related words than did nonresponders.

Adolescent↗
PubMed1991

Cerebral laterality, symptoms, and diagnosis in psychotic patients.

A dichotic nonsense test and a dichotic word test were used to assess cerebral laterality in 100 acutely symptomatic inpatients. Schizophrenic patients had significantly lower right ear advantages (REAs) than healthy controls, depressed patients, or schizoaffective patients. Manic patients did not differ from any other group, but manics with lower REAs were likely to have more symptoms of thought disorder than of mood disturbance while the reverse was likely to be true for manic patients with higher REAs. A subset of patients tested after symptom remission showed recovery-related increases in REA on the nonsense test and decreases on the word test, replicating previous findings. Those schizophrenics with evidence of greater disease-related decreases in REA on the nonsense than on the word test had predominantly negative symptoms whereas those with similar changes on the two tests had predominantly positive symptoms. These observations suggest the hypothesis that positive symptoms are related to overactivation of a dysfunctional left hemisphere by right hemisphere input while negative symptoms reflect a left hemisphere deficit state.

Adult↗
PubMed1991

Failure at task-specific regional brain activation: new conceptualization of a disease entity.

The current diagnostic system in psychiatry is symptom-based, as described in detail in DSM-III-R. In other branches of medicine the logic of diagnosis is based on knowledge of the normal function of the organ system affected by disease, and direct measures of pathophysiological process play an increasingly important role in clinical practice. New understanding of normal brain function has opened the way for psychiatry to begin to follow this path and develop a brain-based, rather than symptom-based, nosology. Different models of normal brain function, however, suggest quite different theoretical and research approaches. One way in which these models differ is the degree to which they link specific functions (and illnesses) to specific anatomic locations. In a previous paper I discussed the value of adopting a model of brain function that includes important roles for the processes that integrate multiple brain regions into ever-changing functional constellations. In this paper I have proposed the existence of a disease characterized by abnormality in the general physiological mechanism of task-specific regional brain activation. This is not an etiologic diagnosis and therefore presents nothing more than a symptom-based diagnosis about the cause of the disorder. However, I predict that this diagnosis will define a group of patients that is more homogeneous with respect to both clinical course and etiology than do the current symptom-based diagnoses to which these patients would otherwise be assigned. Furthermore, it may be possible to develop new treatments to address this physiological dysfunction.

Cerebrovascular Circulation↗