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M Hiscock

Publications and source records attributed to M Hiscock.

At least 37 records · Page 2Linked to original sources
PubMed1995

Is there a sex difference in human laterality? II. An exhaustive survey of visual laterality studies from six neuropsychology journals.

The contents of six neuropsychology journals (98 volumes, 368 issues) were screened to identify visual half-field (VHF) experiments. Of the 516 experiments identified, 42% provided information about sex differences. Sixty-eight experiments yielded a total of 92 sex differences, 23 of which met stringent criteria for sex differences in laterality. Of the 20 sex differences satisfying stringent criteria and lending themselves to interpretation in terms of the differential lateralization hypothesis, 17 supported the hypothesis of greater hemispheric specialization in males than in females. The 17 confirmatory outcomes represent 7.8% of the informative experiments. When less stringent criteria were invoked, 27 outcomes (12.3% of the informative experiments) were found to be consistent with the differential lateralization hypothesis. Six findings were contrary to the hypothesis. The results, which closely resemble results for auditory laterality studies, are compatible with a population-level sex difference that accounts for 1 to 2% of the variance in laterality.

Adult↗
PubMed1994

Is there a sex difference in human laterality? I. An exhaustive survey of auditory laterality studies from six neuropsychology journals.

The entire contents of six neuropsychology journals (98 volumes, 368 issues) were screened to identify auditory laterality experiments. Of the 352 dichotic and monaural listening experiments identified, 40% provided information about sex differences. Among the 49 experiments that yielded at least one significant effect or interaction involving the sex factor, 11 outcomes met stringent criteria for sex differences in laterality. Of those 11 positive outcomes, 9 supported the hypothesis of greater hemispheric specialization in males than in females. The 9 confirmatory outcomes represent 6.4% of the informative experiments. When less stringent criteria were invoked, 21 outcomes (14.9% of the informative experiments) were found to be consistent with the differential lateralization hypothesis. The overall pattern of results is compatible with a weak population-level sex difference in hemispheric specialization.

Adult↗
PubMed1993

Dual task performance by patients with left or right speech dominance as determined by carotid amytal tests.

Patients who had their speech dominance determined by carotid Amytal testing were evaluated with a dual task procedure consisting of reading and finger tapping. As expected, the asymmetry of interference between tasks varied with speech dominance. Patients with left hemisphere speech tended to show greater interference in the right hand whereas patients with right hemisphere speech showed greater interference in the left hand. Since the right hemisphere dominant patients were also right-handed, the results suggest that interference effects are more closely linked to speech than to motor dominance.

Adolescent↗
PubMed1993

Children's ability to shift attention from one ear to the other: divergent results for dichotic and monaural stimuli.

In three experiments, 5- to 8-year-old children reported digit names from one ear for 30 trials before shifting attention to the other ear. Stimuli were presented dichotically in Experiment 1 and monaurally in Experiments 2 and 3. Dichotic stimulation yielded not only a right-ear advantage but also a priming effect that reflects difficulty in shifting attention in either direction. With monaural stimulation, however, performance with the second ear to be monitored was superior to performance with the first ear. The priming effect thus depends on interaural competition and cannot be attributed to general factors such as fatigue or motivation.

Attention↗
PubMed1993

Overcoming the right-ear advantage: a study of focused attention in children.

Several studies indicate that normal right-handed children of various ages show a right-ear advantage (REA) for dichotic verbal stimuli even when instructed to attend to the left ear. Other evidence, however, suggests that selective listening ability begins to develop in early childhood and that children reliably can overcome the REA by the age of 8 or 9 years. We used a signal detection procedure to address this apparent contradiction. In the first of two experiments, 58 children in two age groups (M = 7 and 10 years) were able to overcome the REA for dichotic consonant-vowel (CV) stimuli when instructed to focus attention on the left ear. Success in detecting and localizing signals from the left ear, as reflected in hit rates, was independent of age and reading level. A second experiment, in which strings of dichotic monosyllabic words were presented to 56 children at the same two age levels, yielded similar results. These findings challenge the claim that ability to overcome the REA when attending to the left ear reflects an abnormality of cerebral functioning.

Attention↗
PubMed1993

Complex reactions requiring empathy and knowledge. Psychological aspects of acute pain.

1. Pain may change the personality: some people can become irritated with the disruption caused to their life by pain. 2. Nurses' attitudes may affect the way patients express their pain. 3. It is essential to provide continuity of care and clear communication channels, not only between nurses and patients, but between all members of the healthcare team.

Acute Disease↗
PubMed1992

Direction of lateral eye movements as an index of cognitive mode and emotion: a reappraisal.

Three experiments were designed to determine the effects of cognitive and emotional questions on subjective ratings, lateral eye movement (LEM) incidence and LEM direction. Although the cognitive content of questions affected subjective ratings and the incidence of LEMs, emotional content had an effect only on subjective ratings. Neither cognitive nor emotional content influenced LEM direction. The results raise doubts about the sensitivity of LEM direction as an index of lateralized cerebral processing.

Cognition↗
PubMed1992

Age-related differences in concurrent-task performance of normal adults: evidence for a decline in processing resources.

A concurrent-task paradigm was used to investigate age-related differences in the attentional capacity of 92 right-handed adults. Young, middle-aged, and elderly Ss were compared as they performed speeded, unimanual finger tapping with and without concurrent silent reading, speaking, and maze completion. There were 2 levels of difficulty for each cognitive task. The decrement in tapping rate from the single- to dual-task condition increased linearly with age. Concurrent-task tapping was slowed more by difficult than by easy tasks, and difficult tasks had a disproportionately disruptive effect on the concurrent performance of elderly Ss. The heightened vulnerability of the elderly to concurrent-task effects cannot be attributed parsimoniously to either general slowing or diminution of a specific resource. Instead the results suggest a reduction in a general-purpose processing resource with increasing age.

Adult↗
PubMed1990

Factors affecting interictal spike discharges in adults with epilepsy.

We investigated various factors affecting interictal spike discharges (ISDs) in standard interictal EEGs of 203 consecutive cases with seizure(s). 94 EEGs (46%) showed ISDs. Yield was maximum (68%) when recordings were done within 2 days of a seizure; beyond this period, incidence of ISD did not change with time from the last seizure. EEGs of patients having greater than 12 seizures/year were more likely to contain ISD (68%) than the records of cases with less than 12 attacks/year (37-41%; P less than 0.001). Age and neurological status at the time of EEG, etiology and anticonvulsants did not influence the frequency of ISD. Analysis of serial EEGs (n = 512) from the study group showed that if initial 3 EEGs lacked ISD, yield from further standard EEGs is small.

Action Potentials↗
PubMed1990

Attention deficits in children exposed to alcohol prenatally.

Twenty children with fetal alcohol syndrome or fetal alcohol effect (FAS/FAE) were compared with 20 attention deficit disorder (ADD) children and 20 normal controls on three experimental tasks designed to isolate four different components of attention. Parents completed three questionnaires regarding their child's activity level and overall functioning, and the children completed a short form of an IQ test. The children in each group ranged from 5 to 12 years. Results indicate that although the children with FAS/FAE are significantly more impaired intellectually, their attentional deficits and behavioral problems are similar to those of children with ADD. These findings imply that the treatments known to facilitate learning in children with ADD may also benefit children with FAS/FAE.

Adolescent↗
PubMed1989

Rate and variability of finger tapping as measures of lateralized concurrent task effects.

Using a sample of 48 normal right-handed adults, we assessed the effects of oral reading on concurrent unimanual finger tapping under all combinations of instructional set (speeded vs. consistent tapping), tapping movement (repetitive vs. alternating), task emphasis (reading emphasized vs. tapping emphasized), and tapping hand. Change in tapping rate and variability was measured relative to the corresponding single task control condition. Reading decreased the rate of speeded finger tapping but increased the rate of consistent tapping. In both instances, the right hand was affected more than the left hand. Asymmetries were comparable for repetitive and alternating tapping. When measured in terms of variability, however, effects were largely symmetric. The findings clarify the conditions under which lateralized concurrent task effects are most likely to occur and show that such effects are not statistical artifacts. It appears that subjects attempt to coordinate the timing of concurrent activities and that speech timing is more strongly linked to right-hand control than to left-hand control in right-handers.

Adolescent↗
PubMed1989

Writing posture in right hemiplegic children.

The handwriting posture of 29 children with congenital right hemiparesis was classified according to standard criteria. All 29 children, who ranged in age from 4 to 14 years, were classified unambiguously as noninverted writers. The prevalence of noninverted writing in this sample differs significantly from that reported for the general population of children. The data thus support the claim that neural factors contribute to handwriting posture.

Adolescent↗
PubMed1989

Refining the forced-choice method for the detection of malingering.

For seven years following head trauma, a 45-year-old restaurant owner had claimed that he was unable to work because of impaired memory. A specially designed forced-choice memory test yielded performance significantly below the chance level and thus indicated malingering. This case illustrates some means of increasing the utility of forced-choice malingering tests.

Accidents, Occupational↗
PubMed1988

An anomalous sex difference in auditory laterality.

Eighty right-handed adults (40 females, 40 males) performed a task that entailed detecting and localizing targets within series of dichotic digit names. Analysis of sensitivity scores for each ear revealed an overall right-ear advantage (REA). However, a significant Sex x Ear interaction showed that the degree of asymmetry was greater among females than among males. This sex difference, which is opposite to that previously reported in some dichotic listening studies, contradicts the conclusion that language processing is more completely lateralized in males than in females.

Adolescent↗
PubMed1988

Association of low serum anticholinergic levels and cognitive impairment in elderly presurgical patients.

Low-dose scopolamine, given as presurgery medication, resulted in low levels of serum anticholinergic activity and caused measurable cognitive impairment in 18 psychiatrically healthy elderly patients. The degree of impairment was directly related to serum anticholinergic activity levels and, in the small subgroup of patients scheduled for spinal anesthesia, to CSF anticholinergic activity. Two of the mental status tests used, the Rey Auditory-Verbal Learning Test and the Saskatoon Delirium Checklist, were sensitive enough to detect these mild drug-induced changes, while two other tests, the Mini-Mental State and the Symbol Digit Modalities Test, were not.

Aged↗
PubMed1987

A signal detection procedure eliminates priming biases in dichotic listening.

Dichotic digit names were presented to normal right-handed adults in two experiments, the first of which used a standard free report procedure and the second of which used a signal detection procedure. Prior to each test, a priming bias was generated by having subjects monitor either the left or right ear for 30 selective listening trials. The expected priming effect was found in Experiment 1: ear asymmetry and order of report were altered according to the ear previously monitored. In contrast, no priming effect was observed with the signal detection procedure used in Experiment 2. There was a right-ear advantage in sensitivity irrespective of the ear previously monitored. The findings suggest that priming biases act by altering the order in which multiple stimuli are processed and reported.

Adolescent↗
PubMed1987

Dual task performance in children: generalized and lateralized effects of memory encoding upon the rate and variability of concurrent finger tapping.

Interference between concurrent tasks was used to investigate the brain basis of capacity limitations apparent when children encode information. Seventy-three right-handed children in Grades 1-4 engaged in speeded unilateral finger tapping while encoding a variable number of faces or numbers for subsequent recognition testing. With both face and number encoding, tapping rate decreased as memory load increased. Encoding numbers was more disruptive than encoding faces. Both encoding tasks slowed right-hand tapping more than left-hand tapping, relative to control tapping performance, but had only a bilateral effect on the variability of tapping. Although overall interference was less than that observed with a comparison task (i.e., speaking), the asymmetry of interference was comparable. The results suggest that cerebral lateralization for memory encoding, as well as for speech, is constant across the age range of 6-10 years. Findings regarding developmental change in overall capacity, however, are task specific: interference from speaking but not from memory encoding decreases with increasing age.

Attention↗