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Biomedical subjects

R Condray

Publications and source records attributed to R Condray.

At least 19 recordsLinked to original sources
PubMed2001

Neuropsychological assessment, depression, and past exposure to organic solvents.

This study assessed neuropsychological performance in persons with a history of exposure to organic solvents and nonexposed healthy controls. Structured clinical interviews were also done to determine current Axis I diagnosis of mood disorder to assess the contribution of mood disorder to neuropsychological performance. Solvent-exposed participants were found to have significantly reduced scores on 3 of 5 neuropsychological clusters (learning and memory, visuospatial, psychomotor speed) compared to controls. No differences were found between the groups on measures of general intelligence. Within the exposed group, 50% met current Axis I criteria for mood disorder. Hierarchical multiple regression, controlling for age and education, revealed that mood disorder was significantly related to performance on only the visuospatial domain. There was no association between mood disorder and measures of learning and memory, attention, motor speed, and general intelligence. Higher ratings of past exposure were associated with poorer scores on learning and memory tests and slower times on speeded tests. These findings are consistent with other research documenting deficits in neuropsychological and psychiatric functioning in exposed workers.

Adult↗
PubMed2000

Mood and behavioral symptoms in individuals with chronic solvent exposure.

Psychiatric symptoms have been reported for individuals who experience chronic exposure to low levels of organic solvents. However, it is not known what proportion of such individuals experience psychiatric disorder; which specific disorders may be characteristic of this population; or whether bioaccumulation of lead contributes to the relationship between solvent exposure and psychiatric symptoms. Twenty-nine male journeymen painters and 32 male non-painter control subjects were administered semi-structured diagnostic interviews for DSM-III-R Axis I and Axis II disorders. Career solvent exposure and blood lead levels were also measured. Painters and control subjects did not differ significantly with respect to age, intelligence, or demographic characteristics. Results showed that the probability of being diagnosed with a mood disorder differed significantly in painters (41%) and control subjects (16%). Painters (66%) and control subjects (50%) did not differ for substance use diagnoses. Groups also did not differ for personality disorders involving an onset before 25 years of age. In contrast, painters exhibited a sub-clinical pattern of personality dysfunction involving symptomatology that was measured allowing for late onset (after age 25). Finally, a significant dose-response relationship was observed between career solvent exposure, blood lead level, and personality symptoms. In summary, these data showed an increased rate of psychological disturbance in a significant and substantial number of painters. However, not all painters were so characterized. This overall pattern raises a question regarding a potential role for differential vulnerability, which requires empirical validation.

Adult↗
PubMed2000

Cognitive modulation of midbrain function: task-induced reduction of the pupillary light reflex.

The activation of processing resources has widespread effects in the nervous system. A model of pupillary control systems (Steinhauer S.R. , Hakerem G., 1992. The pupillary response in cognitive psychophysiology and schizophrenia. Ann. N.Y. Acad. Sci. 658, 182-204) had predicted that ongoing cognitive activation should result in inhibition of the light reaction at the level of the oculomotor nucleus, n. III, in the midbrain. In this study, modification of parameters of the pupillary reaction to light were examined during varying task demands. The averaged light reaction was recorded from 33 male and female healthy volunteers during the performance of a serial 7 subtraction task and compared to a 'no task' condition. For 13 subjects, an additional verbalization task with little processing demand (add 1) also was presented. Two types of effects were observed. Firstly, the tonic pupil diameter increased from the no task to the easy (add 1) task, and increased further in the more demanding condition (subtract 7). Secondly, the extent of the phasic light reaction was significantly reduced and the latency at the end of the contraction was significantly decreased in the 'subtract 7' condition compared to both the no task and easy conditions (which did not differ from each other). The locus of interference with the light reaction was the Edinger-Westphal complex of the oculomotor nucleus, which is the motor center for the pupillary sphincter muscles. Descending cortical influences inhibited the activity of the Edinger-Westphal complex. Thus, increasing activation had a tonic inhibitory effect on this center, while higher levels of processing complexity produced a separate component of inhibition that interacted with dynamic activation at this midbrain site. It was suggested that the variation in the light reaction is quantitatively responsive to varying processing loads, and may be utilized as a sensitive metric for a wide variety of cognitive operations.

Adolescent↗
PubMed1999

Modulation of language processing in schizophrenia: effects of context and haloperidol on the event-related potential.

BACKGROUND: Disturbances in language associations were among the first clinical symptoms reported for individuals described as schizophrenic (Bleuler 1911/1950). Currently, associative language disturbance is a diagnostic feature of schizophrenia (American Psychiatric Association 1994); however, the mechanisms that produce this symptom remain unknown. In the present study, two candidate psychological functions were examined: sensitivity to semantic context and expectancy (attention). METHODS: Visual event-related potentials were recorded during a lexical decision task in which semantic relationship and expectancy (relatedness proportions) were varied. Semantic priming processes were compared between 34 male normal control subjects tested once and 37 male schizophrenic inpatients evaluated during their participation in a double-blind haloperidol maintenance therapy and placebo replacement protocol. RESULTS: Schizophrenic patients failed to discriminate between associated and unassociated words, as measured by the amplitude of the N400 component (i.e., absence of the N400 priming effect); however, the overall mean amplitude of N400 did not differ between patients and control subjects. In addition, patients and control subjects did not differ significantly in the amplitude of N400 elicited to associated words or to unassociated words. Finally, the effect of expectancy-based processing on the magnitude of the N400 priming effect did not differ between patients and control subjects. CONCLUSIONS: On the basis of these findings, a tentative hypothesis is suggested that schizophrenic patients are characterized by a pattern of indiscriminate or random spread of activation in their semantic network during the processing of single-word semantic contexts.

Acoustic Stimulation↗
PubMed1998

Poststroke depression and anxiety: different assessment methods result in variations in incidence and severity estimates.

Patients with right and left hemisphere stroke (RH, LH) and a control group (CG) were administered a structured clinical interview (SCID-R) and rating scales for anxiety and depression (Center for Epidemiologic Studies Depression Scale, Beck Anxiety Inventory, and Hamilton Depression Rating Scale). The three groups did not differ when compared for the mean level of distress on the rating scales or frequency of mood or anxiety disorder diagnosis using the SCID-R. By contrast, participants in the LH group were more likely to be classified as distressed using rating scales cutoff scores and on measures of severity when compared only to the RH group. The rating scales were sensitive to psychiatric disorders, but lacked specificity in all groups. There were significant correlations between scales suggesting the rating scales measure a common factor in the controls, while in the stroke groups associations were weaker and less likely to be significant. Together, these results suggest the need for caution in using rating scales of depression and anxiety in neurologic patients and support the notion that these scales are sensitive to distress rather than specific for identifying depressive and anxiety disorders.

Aged↗
PubMed1998

Predictors of involvement in P300 latency in solvent-exposed adults.

Persons with a history of exposure to organic solvents have been shown to have cognitive and personality changes, as well as abnormalities on measures of neurophysiology (e.g., delays in P300 latency). Studies assessing long-term sequelae in exposed persons have been limited, especially those using neurophysiologic measures. This study assessed cognitive event-related potentials (ERPs) in 16 persons with a history of organic solvent exposure at two testings, separated, on average, by 1.5 years. The sample was divided into persons who showed improvement on P300 latency (e.g., reduction in latency of 1.5 SD of control group) and those who did not. Sixty-three percent showed no improvement, whereas 37% showed significant improvement. Recency of exposure and the interaction of exposure duration and history of peak exposure significantly predicted group membership. That is, persons with shorter duration of exposure coupled with no peak exposures and longer time from exposure to test were more likely to fall in the improved group. Substituting age for duration of exposure in the interaction term improved classification of the two groups. The results support previous findings that most exposed persons do not show significant improvements over time. The results further suggest that there is a need to assess factors, such as aging, which may make one more vulnerable to the neurotoxic effects of solvents.

Adult↗
PubMed1997

Neuropsychological performance of journeymen painters under acute solvent exposure and exposure-free conditions.

Journeymen painters were evaluated with a comprehensive battery of neuropsychological tests and compared to demographically similar nonexposed controls. For painters, a cumulative exposure to solvents was estimated from a structured interview that derived an index based on lifetime exposure and exposure in the past year. Painters were tested either shortly after having painted or after an exposure-free interval. Significant between-group differences were found on a cluster of tests measuring learning and memory. Within the painter group, scores on the learning and memory tests were significantly related to the interaction of condition and exposure. That is, those painters who were tested soon after painting and who also had a higher overall lifetime exposure, performed worst on tests of learning and memory. These results are consistent with the view that neuropsychological function--particularly learning and memory--may be compromised in active workers with a history of chronic solvent exposure. Furthermore, both the chronicity of solvent exposure, as well as the acuteness of the exposure, are significant factors in cognitive performance.

Adult↗
PubMed1996

Predicting duration of clinical stability following haloperidol withdrawal in schizophrenic patients.

Although chronic maintenance antipsychotic drug treatment is the most effective way of preventing relapse in schizophrenic patients, it is not very successful. A considerable number of patients relapse on medication, and many others do not take their medications as prescribed after leaving the hospital. Unfortunately, clinicians are not able to identify how long patients will remain clinically stable after drug discontinuation. To develop a model consisting of behavioral and monoaminergic variables to identify the risk of symptom exacerbation, we obtained in the week prior to haloperidol discontinuation global behavioral ratings and cerebrospinal fluid (CSF) values for monoamine metabolites in a sample of 109 DSM-III-R schizophrenic patients. Patients were followed until specific criteria for increases in psychosis were met for up to 1 year and then returned to antipsychotic drug treatment. Cox regression analysis identified predictors of the survival function, or the probability of relapse at a given time drug free. The best model indicated that increased psychosis, decreased anxiety, an increased CSF homovanillic acid (HVA) to 5-hydroxyindoleacetic acid (5-HIAA) ratio, and decreased CSF 3-methoxy-4-hydroxyphenylglycol (MHPG) prior to haloperidol withdrawal were associated with early increases in psychosis. Our study indicates that it is possible to identify those patients who are more likely to remain clinically stable without medication. When the model is validated, it will help clinicians assess the relapse risk over time, lower doses in treatment-resistant patients, and possibly determine the optimal time for aftercare visits following hospital discharge.

Adult↗
PubMed1996

Working memory capacity predicts language comprehension in schizophrenic patients.

The association between language comprehension and working memory capacity was evaluated in 25 male DSM-III-R schizophrenic patients (14 inpatients; 11 outpatients), and in 11 male normal controls (no lifetime DSM-III-R disorder). Patients and controls did not differ significantly on age and education. Language comprehension was examined as a function of two types of processing demand: grammatical complexity (complex versus simple sentences) and presentation rate (accelerated versus conversational). Schizophrenic patients showed significantly reduced language comprehension and decreased working memory capacity for language, compared with controls. Patients showed general difficulty in comprehending accurately, rather than exhibiting problems with specific grammatical structures. Subject groups were highly accurate and did not differ in their ability to perceive the individual words in sentences presented at the accelerated rate (intelligibility). Presentation rate and grammatical complexity affected comprehension accuracy in all groups, however, with increases in rate and complexity producing decreases in understanding. Of most importance, theoretically, is the finding that working memory capacity predicted language comprehension accuracy in both schizophrenic patients and normal controls. Results suggest that language comprehension deficits in schizophrenic patients may involve a general dysfunction that is associated with working memory capacity for language.

Adult↗
PubMed1996

Differential associations of P300 amplitude and latency with cognitive and psychiatric function in solvent-exposed adults.

Cognitive and mood changes are central components of solvent encephalopathy. This study examined event-related potentials in relation to neuropsychological and psychiatric function in solvent-exposed adults. Results revealed that longer P300 latency was associated with poorer cognitive test scores, whereas reduced P300 amplitude was related to increased psychiatric symptomatology. The findings suggest that the cognitive deficits and the psychiatric disturbance following solvent exposure may have different neurophysiological bases.

Adult↗
PubMed1995

Language comprehension in schizophrenia: trait or state indicator?

Language comprehension, measured by the Luria-Nebraska Relational Concepts Factor Scale, was evaluated twice in 15 male DSM-III-R schizophrenic patients during a controlled double-blind haloperidol maintenance (without anticholinergics) and placebo replacement protocol. Fifteen male normal controls were tested once. Patients and controls were matched on age and education. Language comprehension was significantly reduced in patients under both pharmacologic conditions, as compared with controls. Patients' comprehension accuracy did not differ significantly between neuroleptic-treatment and placebo replacement conditions. Patients' comprehension accuracy was independent of positive symptoms, anxiety-depression, measures of clinical course, and CSF and plasma monoamines. Comprehension accuracy was also not associated with patients' educational level or WAIS-R measures of their intellectual and short-term memory functioning. Patients' comprehension performance was significantly associated only with the negative symptom anhedonia-asociality during haloperidol maintenance. Thus, language comprehension in schizophrenic patients was independent of changes in pharmacologic treatment and the positive symptoms of psychosis. Results suggest language comprehension may represent a stable or trait characteristic in schizophrenia.

Adult↗
PubMed1992

Language comprehension in schizophrenics and their brothers.

Disturbances in language functioning may be associated with familial vulnerability to schizophrenia. Language comprehension, measured by the Luria-Nebraska Relational Concepts Factor Scale, was evaluated in 36 schizophrenic probands and their nonschizophrenic adult brothers (n = 41), and in 18 normal controls. Language comprehension performance was a function of psychiatric diagnosis in the brothers. Brothers who met criteria for schizophrenia-spectrum disorders showed significantly reduced language performance compared with unaffected brothers and normal controls. Moreover, abnormal language performance was exhibited by significantly more probands and spectrum-disordered brothers than by the normal controls and the brothers without schizophrenia-spectrum disorders. Finally, language performance was not significantly different for 31 pairs of schizophrenic probands and their brothers. Impaired language comprehension appeared comparatively specific in this sample of relatives, as groups were not significantly different on measures of nonlinguistic concept formation (Wisconsin Card Sorting Test) and general intellectual functioning (WAIS-R Information and Block design). Results suggest that impaired language comprehension is associated with familial vulnerability to schizophrenia, and that this disturbance may be most severe in relatives diagnosed with schizophrenia-spectrum disorders.

Adult↗
PubMed1992

Schizotypal personality disorder in individuals with and without schizophrenic relatives: similarities and contrasts in neurocognitive and clinical functioning.

Schizophrenia-spectrum disorders may reflect the genotype for schizophrenia. One such disorder, Schizotypal Personality Disorder (SPD), was examined as a function of family history of schizophrenia. Clinical profiles and neurocognitive functioning were evaluated in 25 schizotypal subjects (10 SPD with schizophrenic relatives and 15 SPD without schizophrenic relatives), and in 24 normal controls. The primary finding is that vigilance performance was similarly impaired in both SPD groups. An additional neurocognitive impairment, comprehension of grammatical constructions, was observed only in the SPD group with schizophrenic relatives. Of interest, the clinical profiles of the two SPD groups did not differ significantly. These results suggest that schizotypal personality disorder is associated with a continuum of neurocognitive vulnerability that increases as a function of family history of schizophrenia.

Adult↗
PubMed1992

Dissociation of neurocognitive deficits in a monozygotic twin pair concordant for schizophrenia.

Cognitive impairment varies markedly among schizophrenic individuals, although the reason for this is unknown. A monozygotic twin pair concordant for schizophrenia was evaluated using electrophysiological and neurobehavioral measures. Each twin showed a distinctive pattern of deficits; furthermore, clinical course and electrophysiological activity were not consonant with social and neurobehavioral functioning. Results suggest complex interrelationships between neurocognitive functioning and clinical presentation in schizophrenia.

Adult↗
PubMedDate not supplied

Respiratory sinus arrhythmia in persons with organic solvent exposure: comparisons with anxiety patients and controls.

Persons exposed to organic solvents have psychiatric symptomatology and cognitive impairments. The results of several studies have suggested that some psychiatric symptoms in these patients reflect similar reactions observed in patients with anxiety disorders. Respiratory sinus arrhythmia provides an indication of impaired autonomic functioning. Whereas decreased respiratory sinus arrhythmia has been reported in anxiety patients, investigators have also noted that higher respiratory rates in these patients obscure differentiation of respiratory sinus arrhythmia from normal values. In this study, the authors recorded multiple parameters of respiratory sinus arrhythmia under a paced-breathing condition in 28 patients with solvent exposure, in 18 patients with anxiety disorder, and in 31 controls. The authors observed a high 1-y retest reliability for a subset of the subjects. Significantly reduced respiratory sinus arrhythmia was observed in both anxiety and solvent-exposed patients, compared with controls. Maximum mean heart rates/cycle did not differ among groups, but minimum heart rates were significantly lower for controls than for the two patient groups. The findings suggested that reduced respiratory sinus arrhythmia among patients is not related to higher maximum rates but, rather, to a decrease in vagally mediated alteration associated with respiratory changes observed in both patient groups.

Adult↗