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Biomedical subjects

H Klonoff

Publications and source records attributed to H Klonoff.

At least 37 records · Page 2Linked to original sources
PubMed1986

Handedness concordance and intelligence discrepancies in identical twins.

The purpose of this study was to determine if the discrepancy in measured intelligence between identical twins concordant for handedness differed measureably from the discrepancy between identical twins discordant for handedness. If handed concordant and discordant twins did differ in terms of the between twin discrepancy in measured intelligence, then one could infer that congenital factors had caused dissociation of handedness and measured intelligence within a twin set. This finding would support Nagylaki and Levy's contention that the found discordance rates for handedness in identical twins is a function of "pathogenic" congenital factors disrupting the genetically determined handedness pattern. More generally, this finding would also support Satz's model with respect to pathological shifts in handedness due to brain insult either in utero or perinatally. However, in the current study, eight sets of identical twins were examined and no evidence was found to support these hypotheses. Instead, in one set where there was a marked discrepancy in measured intelligence, handedness could not be determined precisely for the twin with the lower intelligence quotient.

Journal Article↗
PubMed1983

Cluster analysis of the WAIS on brain-damaged patients.

In recognition of increased usage of cluster analytic techniques, the current study attempted to examine sampling bounds for tests and subjects on one cluster-analytic procedure. Specifically, the WAIS subtest scores from a heterogeneous group of subjects with CNS involvement were first, factor analyzed and then clustered by means of Ward's hierarchical procedure. This methodology had been previously applied to two different samples of aphasics and aphasia batteries. In both these aphasic studies, an underlying severity dimension of language dysfunction was found. In contrast, in the current study, salient feature groups were found. Moreover, these groups were distributed in a sequential or hierarchical model in terms of specific cognitive deficits. From these data, it is argued that two major parameters in determining the resulting cluster structures are the homogeneity/heterogeneity of the sample and test battery employed. Although such a statement is obvious, the theoretical ramifications are large, in that the cluster structure may be a function of test weighting or sample diversity, not the phenomenon of interest. However, the cluster structures found in the current study were consistent with historical models of cognitive dysfunction and also lend support to hierarchical models of sequential cognitive impairment. These findings are discussed in terms of their clinical and experimental ramifications with respect to grouping subjects in terms of WAIS profiles.

Adult↗
PubMed1982

Shortening the Speech Sounds Perception Test.

Statistical means of shortening the Speech Sounds Perception Test were examined. Stepwise multiple regression analyses indicated that a 30-item version correlated quite highly with the 60-item version. Group means for representative clinical groups were presented, but no strong differences emerged using either version. Inclusion of length of stay and number of previous admissions as covariates did little to enhance the predictive validity of either form. Finally, the correlation of the 30-item test with demographic variables showed that age correlated most, followed by occupational status. these results were interpreted as indicating that the 30-item version could be used while maintaining the clinical utility of this test.

Adult↗
PubMed1981

Severity of impairment or specific types of aphasia: an empirical investigation.

This study examined empirical means of clustering aphasic patients into relatively homogenous and identifiable groups. The method included: (1) examining the intercorrelations of the subtests of the Neurosensory Comprehensive Examination for Aphasia by the means of factor analysis; (2) allowing the subjects to group themselves in homogenous subgroups by means of hierarchical cluster analysis; and (3) comparing the profiles of these groups on the derived dimensions. Four factors accounting for 79.3% of their total test variance were derived which reflected attention/memory; reading ability; verbal-naming ability; and elementary writing skills. With five groups the hierarchical grouping analysis indicated that only 21.5% of the total variability could be ascribed to within group variability. An analysis of variance of the four factor scores found that 66%, 93%, 81% and 79% of the between group variance of each of the respective factors was associated with group membership and the accuracy of membership prediction was 94.1%. Four groups appeared to be distributed on the basis of a severity model of impairment. One group representing 6.3% of the total sample demonstrated a pattern of specific impairment involving a mild level of impairment on attention/memory tasks, a moderate level of impairment on verbal naming tasks and writing skills, and a profound level of impairment on measures of reading skills. The high inter-factor correlations indicated the general nature of language functioning. The results were discussed in terms of the concept of aphasia as a general cognitive deficit.

Aphasia↗
PubMed1977

Head injuries in children: a prospective five year follow-up.

A five year follow-up study was conducted with two groups of head-injuried children. 131 younger than 9 years old at time of injury and 100 older than 9 years. The four aspects studied were neuropsychological function, neurological status, EEG status, and school progress. There was an extended recovery process over time, as well as evidence of a differential rate of recovery for the four aspects measured.

Adolescent↗
PubMed1976

Retest reliability of the Halstead Impairment Index in a normal, a schizophrenic, and two samples of organic patients.

In a 1974 study Matarazzo, et al. reported the test-retest reliability of the Halstead-Reitan Neuropsychological Battery for a sample of normal young men and a comparison group of older Ss with cerebrovascular disease. The present study extended this earlier one by addition of comparable test-retest findings from two additional comparison groups: a sample of chronic schizophrenic Ss and a sample of organic patients who underwent endarterectomy. Despite the lack of comparability across the four samples on many dimensions, including age and test-retest interval, the results again reveal a high degree of clinical as well as purely psychometric reliability for most of the tests in the neuropsychological battery and the additional suggestion for further research that the test-retest instability found for some of the Ss in the schizophrenic sample may, itself, hold promise of differential clinical significance in the diagnosis of a "schizophrenic" vs. "organic" process.

Auditory Perception↗
PubMed1976

The neuropsychological, psychiatric, and physical effects of prolonged and severe stress: 30 years later.

This study investigates the long term or residual effects resulting from severe and extended exposure to stress. The samples were prisoners of war who were intended in Japan (high stress group) or Europe (low stress group) during the Second World War. They were examined in the following three areas: neuropsychological, psychiatric, and physical/neurological. Significant differences were found in all three spheres between the two groups. Second, to examine further the effect of length of internment on these variables, the low stress group was divided into long term and short term internment duration groups, and then the three groups were compared. Significant differences were found among these three groups. These results are discussed in relation to a traditional model of explanation.

Aged↗
PubMed1976

The effects of marijauna on verbalization and thought processes.

The verbal output of subjects in response to 10 cards of the TAT was obtained on two occasions and under placebo, marijauna low and high conditions. The themes were independently rated on 13 variables reflecting thought processes, emotional tone, control aggression, and sexual content by two judges. Significant differential dosage differences were obtained in terms of disruption of cognitive processes, and emotional tone. Moreover, a multivariate analysis yielded a significant discrimination among the three experimental conditions.

Adult↗
PubMed1976

Drug patterns in the chronic marijuana user.

The study examined the drug patterns and attitudes of a heavy marijuana user sample drawn from the local "counter-culture." The results indicate that the heavier marijuana user has a different subjective attitude and perception of the drug's effect than a light user. Second, multiple drug usage is, in general, the current and accepted mode within the sample. Finally, it appears that age of initial usage of a specific agent, duration, frequency of usage, and perceived drug effects may be dependent variables with reference to heavy marijuana and multiple drug usage. With respect to these variables, the question arises concerning what proportion of lighter drug using samples may, with time, adopt heavier and more varied drug patterns.

Adolescent↗
PubMed1975

Medical student change during a psychiatry clerkship: evaluation of a program.

The psychiatry clerkship at the University of British Columbia (U.B.C.) emphasizes the teaching model of the student as primary therapist. In the adult program this takes the form of a ward in which clinical clerks are the primary medical agents. In the child program each clerk assesses and treats a new family referral. While the student-ward model has been described previously, this is the first report which attempts to evaluate some aspects of this innovative approach to teaching clinical psychiatry. Student knowledge, attitudes, personality attributes, and expectations were assessed at the beginning and end of the eight-week rotation, and the changes are described. Principal findings included significant differences in the following: psychiatric knowledge, attitudes about psychiatric illness, ratings of the students by the psychiatrist-supervisor, and some student personality characteristics. Most students had rotation experiences which went beyond prior expectations. The changes which occurred were thought to be important, although modest. The implications of the changes are discussed. The level of the patient care in the programs described compared favorably with similar situations in which residents are the primary therapists.

Attitude↗
PubMed1975

A problem-oriented system approach to analysis of treatment outcome.

Data on 90 psychiatric patients' perceptions of the course and outcome of hospitalization were gathered using a problem-oriented system. Patients were interviewed on admission, at discharge, and at two follow-up intervals. Therapists perceptions of patients' problems and their severity were also assessed on patients' admission and at discharge. Although the absolute number of problems reported by patients increased over time, there was a significant decrease over time, there was a significant decrease in the level of distress associated with problems on both patients' and therapists' ratings. The dynamics of this improvement are discussed from the perspectives of both patients and therapists.

Adult↗
PubMed1975

Measuring staff attitudes toward computerization.

The authors developed and tested an 88-item scale designed to measure staff attitudes toward and knowledge about computers. A questionnaire was completed by 42 staff members at a psychiatric unit of a hospital where a health information system was being implemented; 28 of the staff members had attended a two-and-one-half day course on computer systems. Those who had completed the course had more favorable attitudes toward computerization than the 14 who did not. The authors described the findings and discuss their implications.

Adult↗
PubMed1974

Marijuana and driving in real-life situations.

It is evident that the smoking of marijuana by human subjects does have a detrimental effect on their driving skills and performance in a restricted driving area, and that this effect is even greater under normal conditions of driving on city streets. The effect of marijuana on driving is not uniform for all subjects, however, but is in fact bidirectional; whether or not a significant decline occurs in driving ability is dependent both on the subject's capacity to compensate and on the dose of marijuana. For those subjects who improved their performance, the explanation may lie in overcompensation and possibly the sedative effect of the drug. Whereas the street portion of this study approximated normal driving conditions, it should be emphasized that the context of the driving experience een on city streets was experimental. the design of this study maximal safeguards in terms of a dual control vehicle and a driver observr; in addition, the subjects were proffessionally screened and, with rare exception, they were emotionally stable. Given the experimental setting and set, the safeguards, and the nature of the study sample, idiosyncratic behaviour that might occure under normal driving condition would be less likely to occur in a study such as this. Other identified factors might lead to more stringent conclussions regarding the effects of marijuana on driving.The first is night driving, which may be more stressful. But an even more important unanswered question is the cumulative effect of alcohol and marijuana on driving (64 percent of the study sample reported alcohol in combination with marihjuana before driving). Third, the doses of marijuana used in this study were within the range of social marijuana usage(1); more heroic doses might be taken before driving. Fourth, the effect of marijuana on reactions and decision during high speed is still another unknown. What are the recommendations that emarge from this study? Driving under the influence of marijuana should be avoided as much as should driving under the influence of alcohol. More investigation is urgently required-and high priority should be given to studies that approximate normal conditions of driving and in which alcohol and marijuana are administered to the same subjects.

Adult↗
PubMed1973

Neuropsychological effects of marijuana.

This study assigned 81 non-naïve subjects, divided into low- and high-dose groups, to four experimental conditions (marijuana/marijuana, marijuana/placebo, placebo/marijuana and placebo/placebo) for two sessions separated by about one week. The low dose was 4.8 mg. Delta(9)-THC followed by 2.4 mg. one hour later. The high dose was 9.1 mg. followed by 4.5 mg. one hour later. A battery of neuropsychological tests was administered.The low dose produced generalized impairment of all mental processes (concept formation, memory, tactile form discrimination and motor function) and the effect was generalized to all modalities. The high dose resulted in more extensive impairment, again generalized.The drug effects noted were explained in terms of generalized impairment of central integrative processes. The effects of marijuana on learning as well as memory were explained in terms of impaired output (recall), but the impairment was transient.

Adult↗
PubMed1973

Strategy and tactics of marijuana research.

BEFORE UNDERTAKING MARIJUANA RESEARCH, CERTAIN DEMANDS MUST BE MET IN THE FOLLOWING AREAS: educational and health facilities, the legal position, funding, Food and Drug Directorate regulations and law enforcement. Methodological problems include those concerned with pharmacology, nature of effect, set, setting, subjects, dependent variables and controls. The second portion of this paper describes the methodology and findings of a clinical study of 81 volunteers, selected according to specified criteria, screened psychiatrically and psychologically, then assigned to one of seven experimental groups. Dosage and smoking procedure were standardized for both marijuana and placebo. The experience was evaluated subjectively by the volunteers at the end of each experimental session and again on the following morning.

Adult↗