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Biomedical subjects

M Hiscock

Publications and source records attributed to M Hiscock.

54 records · Page 3Linked to original sources
PubMed1986

Concurrent performance of rhythmically compatible or incompatible vocal and manual tasks: evidence for two sources of interference in verbal-manual timesharing.

Forty-two normal, right-handed adults performed rhythmic finger tapping with the left or right hand while concurrently reciting sentences that were either compatible or incompatible with the rhythm being tapped. Both kinds of sentences slowed tapping equally, and the interference was lateralized so that the right hand was affected more than the left. In contrast, the regularity of finger tapping was disrupted to a much greater degree by incompatible sentences than by compatible sentences, and the effect was comparable in the left and right hands. The results implicate two mechanisms of verbal-manual interference--capacity limitation and timing constraints--and thus reconcile certain inconsistencies among findings from previous concurrent-task studies.

Adolescent↗
PubMed1986

The role of myo-inositol in multiple sclerosis.

Myo-inositol was given orally to nine multiple sclerosis patients and nine healthy control subjects. Pattern reversal evoked potential testing was used to assess its effect. The principal positive wave increased in amplitude, duration and area in a dose-dependent manner in the multiple sclerosis group compared with controls. Cerebrospinal fluid concentrations of myo-inositol in multiple sclerosis and controls were similar. The significance of these observations is discussed in relation to recent discoveries in inositol phospholipid function.

Adult↗
PubMed1985

The sex difference in dichotic listening: multiple negative findings.

Verbal dichotic listening tests were administered to 477 normal, right-handed adults in five consecutive experiments. None of the five separate analyses yielded a significant sex difference in degree of ear asymmetry, nor was a significant difference found when data were pooled. Supplemental analyses provided some evidence of a sex difference among subjects without familial sinistrality. Nonetheless, subjects' sex accounts for a very small proportion of the total variance in ear asymmetry.

Adolescent↗
PubMed1985

Effects of induced anxiety and question content on the direction and frequency of lateral eye movements.

Lateral eye movements were recorded electrically as 39 right-handed adults attempted to answer 48 questions that had been rated for anxiety content, visual imagery and difficulty. Subjects were assigned randomly to either a high or low anxiety treatment group. The anxiety treatment increased ocular motility and visuospatial questioning decreased motility, but neither variable had a significant effect on the direction to which the eyes were moved. The anxiety content of questions affected neither the number nor direction of gaze shifts. The results fail to support previous claims that lateral eye movements reflect the cerebral lateralization of emotion.

Adolescent↗
PubMed1985

Differential cerebral involvement in perceiving Chinese characters: levels of processing approach.

Three experiments were designed to determine the accuracy and latency with which right-handed Chinese university students (12 females and 12 males) recognized Chinese characters in the left and right visual half-fields (VHFs). The experiments varied in the "depth" of processing required. Experiment 1 was a lexical decision task in which the configuration of the stimulus (a real Chinese character or the mirror image of a real character) determined whether the grapheme was an actual character. Experiment 2 required phonological processing; i.e., subjects had to decide whether a character (or a foil) matched the sound of an orally presented Chinese character. Experiment 3 required semantic processing; i.e., subjects had to decide if a character (or a foil) belonged to a particular semantic category. In each experiment, single characters were presented unilaterally for 150 msec. There was a significant right VHF superiority for accuracy scores for Experiments 2 and 3 but not for Experiment 1. None of the experiments yielded significant visual asymmetries in reaction time. The results do not support previous claims of orthography-specific laterality, but instead show that laterality effects for morphemic stimuli vary with the orthographic, phonological, and semantic processing demands of the task.

Adult↗
PubMed1985

Effects of eye movements on the recognition and localization of dichotic stimuli.

Three experiments examined the effect of gaze shifts on overall performance and ear differences in dichotic listening. In the first two experiments, lights were switched on and off so as to induce rightward, leftward, or upward gaze during dichotic stimulation. The dichotic material consisted of musical passages in Experiment 1 and two kinds of verbal material in Experiment 2. Vertical eye movements enhanced the accuracy of identification of music but not verbal material. The lateral direction of eye movements affected subjects' ability to localize targets in Experiment 1: localization was more accurate in the direction toward which subjects were looking. In the third experiment it was found that optokinetic nystagmus (OKN) influenced the asymmetry of performance on a dichotic consonant-vowel (CV) test. The right-ear advantage was greatest when the OKN drum rotated from left to right and least when it rotated from right to left. The effect was due to corresponding variation in left-ear scores. Possible mechanisms through which shifts of gaze affect auditory identification and localization are proposed.

Adult↗
PubMed1984

The effect of asymmetrically focused attention upon subsequent ear differences in dichotic listening.

In a series of four experiments, normal right-handed adults engaged in dichotic listening with free-report instructions after having completed a selective listening task. The usual right-ear advantage (REA) for dichotic digit names was altered according to the ear previously monitored. Most notably, the REA was absent among subjects who had monitored the left ear. Additional experiments showed that the "priming bias" is material-specific; it did not occur if consonant-vowel nonsense syllables (CV's) were substituted for digit names in either the selective listening task or the subsequent free-report test. The findings help clarify the nature of one of the attentional mechanisms that influence auditory laterality.

Adolescent↗
PubMed1982

The lengthy persistence of priming effects in dichotic listening.

A dichotic digits task, with selective listening instructions, was administered to 72 normal, right-handed children. The interval between monitoring one ear and monitoring the other ear was either 5 min or 1 week. Ear asymmetry depended on the order in which the ears were monitored: only children who listened first to the right ear showed a right-ear advantage. This order, or priming, effect was equally strong irrespective of the interval over which attention was switched. The results show that attentional biases may exert a strong and enduring influence on ear asymmetry.

Attention↗
PubMed1982

Verbal-manual time sharing in children as a function of task priority.

Eighty-three normal, right-handed children performed unimanual finger tapping recitation of a tongue twister, and both tasks concurrently. Trade-offs in dual-task performance were measured as the priority assigned to each task was manipulated. Irrespective of task priority, speaking interfered to a greater degree with right-hand tapping than with left-hand tapping, but the effect of tapping upon verbal production and speech errors was not lateralized. The asymmetric effect of speech upon tapping, which was seen in 85.5% of the children, cannot be attributed to the disparity between hands in baseline tapping rate. The findings suggest that time-sharing asymmetry reflects cerebral lateralization of speech, but only some of the results would be predicted on the basis of a functional distance principle of cerebral organization.

Cerebral Cortex↗
PubMed1977

Eye-movement asymmetry and hemispheric function: an examination of individual differences.

The relationship between lateral eye movements and selected individual characteristics was examined in a group of 81 right-handed adult males. Ss answered 20 verbal and 20 visuospatial questions in one of three experimental conditions while their eye movements were being recorded electrically. Multiple regression analyses were used to predict the proportion of eye movements to the right on the basis of spatial and verbal test scores, questionnaire responses concerning imagery and verbal processes, a self-report measure of values and interests, and choice of academic major. No significant relationships were found. Even the most consistent "left movers" and "right movers" did not differ in the manner suggested by a model of eye-movement asymmetry based upon individual differences in cerebral function.

Career Choice↗
PubMedDate not supplied

Development and psychometric evaluation of the Environment-Behavior Interaction Code (EBIC).

BACKGROUND: Although the behavioral changes with progressive dementia are seen to increasingly depend on the environmental context until late stage disease, measurement has not reflected this interaction in real time to allow examination of antecedents to disruptive behavior. OBJECTIVES: To develop and evaluate the psychometric properties of the Environment-Behavior Interaction Code (EBIC) for use in dementia care research with either sequential or nonsequential analyses of behavioral data. METHOD: Development of the computer-based (sequential event format) EBIC provided an observational coding system to classify all behavior and environmental context in real time, so that the probability of social environmental antecedents to resident disruptive behavior could be estimated. A checklist (interval format) EBIC, based on the same behavioral taxonomy, was developed for clinical outcome research. A total of 158 elderly residents of dementia care units were purposively selected from three large long-term care facilities for the psychometric study components. RESULTS: Psychometric results indicated significant (p < 0.01) known-groups validity for the disruptive behavior construct, which was defined as a composite of aversive, harmful, and high intensity neutral behavior. Interrater agreement for the event format of the EBIC was estimated by average kappa (0.65) and percentage agreement (78%). For the interval format, the mean interrater kappa was 0.80 with 96% agreement. Stability of the event format using a 2-week retest interval ranged from r= .50 (positive behavior) to r = 0.73 (negative behavior, defined as aversive + harmful). On replication with a new sample, stability was higher for positive (r = 0.92) and negative (r = 0.95) components, and for composite scores of nondisruptive (positive + low intensity neutral; r = 0.65) and disruptive (r= 0.85) behavior. CONCLUSION: This research provided support for the reliability and validity of both event and interval EBIC formats. Measurement using the EBIC taxonomy has applicability to dementia care research questions that call for either sequential analysis of social interactions or nonsequential analysis of behavioral outcomes in intervention studies.

Aged↗
PubMedDate not supplied

Learning disability subtypes in children with neurofibromatosis.

A high incidence of learning disabilities (LD) has been reported in children with neurofibromatosis Type 1 (NF-1), and many children affected with this disease are thought to have a form of LD that is characterized by selective visuospatial and motor deficits. However, the evidence is subject to sampling biases and is limited by the clinical-inferential methods used to classify children into LD subtypes. In the present study, objective statistical methods were used to categorize LD in 105 children with NF-1 between the ages of 6 and 18 years. A cluster analysis of achievement test scores yielded 10 groups; 6 of which met our criterion for academic deficiency. An analysis of neuropsychological data for 72 children with academic deficiencies with complete neuropsychological data yielded three groups: a neuropsychologically normal group (n = 28), a group with general academic deficiencies (n = 34), and a group with visuospatial-construction deficiencies (n = 10). The low incidence of visuospatial-constructional deficits and the absence of cases involving pure linguistic deficits is notable.

Achievement↗
PubMedDate not supplied

Perception of pain management in a hospital in Thailand.

After winning the American Medical International Nurse Scholarship Award in 1990, the author went to the Chulalongkorn University Hospital in Bangkok to study how the nurses in the surgical intensive care unit manage patients in acute pain.

Hospitals, University↗