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J Herron

Publications and source records attributed to J Herron.

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

EEG spectra in dyslexic and control boys during resting conditions.

We studied the resting eyes open and eyes closed EEG in carefully screened samples of 9-13-year-old dyslexic and control boys within a 2-cohort cross-validation design with repeat testing 1-3 years later. We found: no difference between groups in delta or theta activity in either cohort or in repeat testing 1-3 years later; in the dyslexics, decreased beta (19-24 c/sec) activity at bilateral central, parietal and mid-temporal leads referenced to vertex; inconsistent group differences in the alpha band: the first cohort dyslexics had lower alpha power than did the controls, but there was no group difference in the second cohort; and significant relative delta differences between groups in the first cohort, which were shown to be a statistical artifact of the use of relative power. We conclude that: dyslexia per se is not associated with increased absolute power in the delta and theta bands; lower power in the high beta band is reliably found in these samples of dyslexics without other disorders; and alpha power levels are not consistently lower in the dyslexic group.

Alpha Rhythm↗
PubMed1986

Suppression of histamine-induced wheal response by loratadine (SCH 29851) over 28 days in man.

Five groups of 12 healthy volunteers each received in double-blind, randomized fashion oral b.i.d. doses of 10, 20, or 40 mg loratadine, 12 mg chlorpheniramine maleate (CTM), or placebo for 28 days. Histamine and saline were injected intradermally into opposite arms at baseline and at specified times following treatment on days 1, 3, 7, 14, 21, and 28. Notable suppression of adjusted wheal formation (histamine-induced minus saline-induced) occurred within two hours after the first dose of each active treatment on day 1. In general, throughout the treatment period, suppression of adjusted wheal formation by all doses of loratadine was significantly greater than by placebo. Suppression by 10 mg loratadine was comparable to CTM, and 20 and 40 mg loratadine were significantly greater than CTM. Suppression of wheal formation by loratadine during the treatment period and during five days posttreatment were dose related. The continued effectiveness of loratadine throughout the 28 days suggests that tolerance to loratadine did not develop in this study. Sedation occurred in 8 of 12 subjects receiving CTM, 1 of 12 receiving 10 mg loratadine, and 1 of 12 receiving placebo.

Adolescent↗
PubMed1984

Regional brain activity in dyslexic and control children during reading tasks: visual probe event-related potentials.

Event-related potentials (ERPs) elicited by task-irrelevant visual stimuli were recorded from 34 control and 32 dyslexic 10- to 12-year-old boys while they performed silent and oral reading at two levels of difficulty. All subjects were extensively screened for neurological problems, IQ, and sensory acuity. Specific features of the ERPs were affected in amplitude and latency by the experimental variables: group membership, oral vs. silent reading, difficulty level, and recording site (within and between hemispheres). A specific effect of difficulty on the central and parietal ERP was seen in the dyslexics but not the controls. Different patterns of asymmetry were found for the two groups in silent vs. oral reading at midtemporal placements. A marked asymmetry (R greater than L) was found at the midtemporal region for both groups.

Attention↗
PubMed1983

Dyslexic children have normal vestibular responses to rotation.

We examined the rotational vestibular responses of carefully screened dyslexic and control populations (34 dyslexics and 33 controls). The subject groups had equivalent performance IQs but differed significantly on verbal IQ and on silent and oral reading. Children with significant neurologic, visual, or hearing deficits were excluded. We measured eye movements provoked by sinusoidal rotation of the subjects (in total darkness) at low frequencies (0.01 to 0.16 Hz). Gain, phase, and preponderance (asymmetry) of the responses were calculated from the eye velocity and stimulus velocity waveforms. There were no differences between the groups in any of these measures. We conclude that there are no clinically measurable differences in this aspect of vestibular function in our carefully selected populations of dyslexic and control children.

Child↗
PubMed1983

Predictive eye movements do not discriminate between dyslexic and control children.

Pavlidis has suggested that predictive saccadic tracking eye movements distinguish between reading disabled and normal children. We have examined saccadic eye movement tracking in 34 dyslexic and 33 control subjects, between 10 and 12 yr old. The subjects were equivalent in performance IQ (WISC-R), with differences between verbal and performance IQ of less than 30 points. Children with neurological, visual or auditory deficits or histories of emotional problems and hyperactivity were excluded. There were no differences between the groups on the eye movement tracking task when scored objectively by computerized analysis of the eye movement records, or by ranking of the records by an experienced observer. Our results (and those of other recent studies) fail to support Pavlidis' contention that eye movements hold the key to dyslexia.

Child↗
PubMed1983

Tracking eye movements are normal in dyslexic children.

We measured saccadic and smooth eye tracking movements in 34 dyslexic and 35 control subjects and were unable to show differences in any of the tasks or parameters measured. Subjects were carefully screened for neurological, optometric, audiological, and behavioral problems before admission to the study. We suggest that differences between our results and those of previous investigators are based on sampling differences. We conclude that while there may be children with reading disorders secondary to visual or oculomotor deficits, dyslexia can and does exist independent of such deficits. Because, in this and other studies, we have ruled out peripheral involvement, we feel that dyslexia is primarily a deficit of central information processing of written or spoken material.

Child↗
PubMed1979

Cerebral specialization, writing posture, and motor control of writing in left-handers.

It has been suggested that the inverted hand position of left-handers during writing indicates the left hemisphere of their brain is linguistically specialized and that the writing of these left-handers may be controlled via ipsilateral pathways. Electroencephalograph alpha asymmetry measures at central and parietal leads, as well as dichotic tests, differentiated right-handers from left-handers, but not inverters from noninverters. Electroencephalograph differences between hand posture groups did appear, but only at occipital leads during reading and writing tasks. Regardless of hand posture or speech lateralization, the right central region of the brain is significantly involved in the control of left-handed writing.

Auditory Perception↗
PubMed1979

Choice of handedness measures in studies of hemispheric specialization.

Left-and right-handers have been reported to differ in lateral hemispheric specialization for cognition. We compared different methods of dividing subjects into handedness groups: preference(a 12-item questionnaire), performance(speed, strength, dexterity), and preference plus performance, and determined which method of handedness classification indicated the greatest group differences on EEG and dichotic measures of lateral specialization. All handedness measures were significantly intercorrelated. These handedness measures were significantly correlated with the dichotic test over the whole population but were significantly correlated with EEG asymmetry only in females. Scoring degree of handedness showed significant relationships to lateral specialization which were not seen when subjects were classified into discrete handedness groups. Ambidextrous subjects performed as well as right- or left-handers on unimanual tasks despite a lack of hand preference. The hand used for writing was shown to be too limited to be used as the sole index of handedness in studies related to cognition.

Adult↗