Charles G. Matthews

The Effect of Early Versus Late Onset of Major Motor Epilepsy upon Cognitive-Intellectual Performance

Performance on the Wechsler Adult Intelligence Scale and Halstead neuropsychological measures were investigated in two groups of adult subjects with major motor epileṕsy of early (0 to 5 yr) and later (17 to 50 yr) onset, and in two groups with early and later onset of brain damage without epilepsy. The two groups with early onset earned poorer scores on most tests than did we two groups with later onset. The findings suggest an adverse effect of cerebral dysfunction of early onset, whether accompanied by major motor seizures or not. Subjects with early onset of major motor seizures scored significantly lower on 9 of 14 measures than subjects in any other group, none of which showed significant intergroup differences in the dependent variables employed. The results support the conclusion that early age of onset of major motor seizures is more apt to result in impairment of mental abilities in adult life than is later onset of seizures or early or late onset of brain damage uncomplicated by epilepsy.

Effect of Major Motor Seizure Frequency upon Cognitive-Intellectual Functions in Adults

Wechsler Adult Intelligence Scale and Halstead neuropsychological performances were investigated in three groups of adult subjects with major motor epilepsy classified according to low, moderate, and high seizure frequency. The groups were equated on seizure duration and age at onset variables. On 7 of the 14 psychological measures employed, significant between‐group differences were obtained, with poorest, intermediate, and best test scores associated with the high, moderate, and low seizure frequency groups, respectively.

Differential Psychological Performances in Major Motor, Psychomotor, and Mixed Seizure Classifications of Known and Unknown Etiology

Comparisons on an extensive battery of psychological tests were made in the following eight groups of patients. Three groups with seizures of known etiology (major motor, psychomotor, and mixed major motor and psychomotor) were matched on age, education, and diagnostic classification and were compared with three similar groups of seizure patients in whom etiology was unknown, and with a control group and a group of brain damaged patients without epilepsy. Using intergroup differences on the Halstead Impairment Index as a summary measure of performance level, the results indicated that all groups except the group with psychomotor epilepsy of unknown etiology demonstrated significant impairment in comparison to control subjects. No differences were found between the test performances of controls and subjects with psychomotor epilepsy of unknown etiology. Patients with psychomotor epilepsy of unknown etiology performed at significantly better levels than did patients with major motor seizures of unknown etiology. The groups with psychomotor seizures of known etiology achieved higher mean scores on each test variable than did the group with major seizures of known etiology, although the differences were not nearly as clear as in the comparisons involving psychomotor and major motor seizures of unknown etiology.

Topical Review: La Crosse and Other Forms of California Encephalitis:

The California serogroup viruses are mosquito viruses that cause human infections on five continents. They are maintained and amplified in nature by a wide variety of mosquito vectors and mammalian hosts; they thrive in a remarkably wide variety of microclimates (eg, tropical, coastal temperate marshland, lowland river valleys, alpine valleys and highlands, high boreal deserts, and arctic steppes). In 1993, California serogroup viruses caused 71% of all cases of arboviral illness in the United States, principally La Crosse encephalitis.1 The 30 to 180 annual cases of La Crosse encephalitis represent 8% to 30% of all cases of encephalitis, rendering this illness the most common and important endemic mosquito-borne illness in the USA. Subclinical or mild infections are much more common. Methods and results acquired from intense study of California serogroup viruses have been applied, with benefit, to the study of the ecology and pathogenesis of many more serious human arboviral illnesses. The evolutionary potential of viruses, with particular reference to the development of more virulent strains, has been studied more closely in the California serogroup viruses than in almost any other agent of human disease. (J Child Neurol 1999;14:1-14).

Effect of Early Versus Late Onset of Major Motor Epilepsy on Cognitive-Intellectual Performance: Further Considerations

Two groups of adult patients, one with early (0–5 years), the other with late (10–15 years) age of seizure onset, were compared on 14 variables derived from the Wechsler Adult Intelligence Scale (WAIS) and Halsteads neuropsychological measures. The groups were matched for duration of the disorder and seizure frequency, and all subjects (Ss) had unequivocal histories of major motor seizures. The group with early age of onset obtained significantly lower WAIS, Verbal IQ, Performance IQ, and Full Scale IQ values than the group with late age of onset. No significant intergroup differences were obtained on Halsteads measures, although the performances of both groups were impaired vis‐a‐vis non‐neurological control expectancy. The results suggest that early onset age, as operationally defined in this study, has a specific differential influence which is restricted to psychometric intellectual functions as measured by the WAIS in groups matched for seizure duration and seizure frequency.

Psychometric and adaptive abilities in epilepsy with differential etiology.

Comparisons on an extensive battery of neuropsychological tests including the WAIS and Halsteads measures were made in the following four groups: (N = 51 in each group): 1, controls; 2, patients with verified brain damage but without epilepsy; 3, brain‐damaged patients with epilepsy matched for type of brain damage with the patients in Group 2; 4, patients with epilepsy of unknown etiology matched with the patients in Group 3 for type of seizures. Age and education matches were achieved across the four groups. The results of the study indicated that the presence of epileptic seizures was associated with significantly lower psychometric and adaptive ability levels than those found in normal control subjects. These test score differences occurred both in epileptic patients whose epilepsy was of unknown etiology and in epileptic patients with verified cerebral pathology. However, comparisons of two groups matched for type of pathology, but with and without seizures, did not result in additional significant impairment in the seizure group. These results suggested that epileptic manifestations, regardless of etiology, resulted in significant impairment of adaptive and psychometric abilities, but that in those epileptic patients in whom verified lesions could be established, the ictal episodes per se did not result in significant additional cognitive impairment when compared to non‐epileptic patients matched for type of pathology.

The role of neuropsychology in the assessment and treatment of persons with epilepsy.

Several areas of current interest in the neuropsychology of epilepsy are briefly reviewed in this article. These include variables pertaining to seizures, seizure history, antiepileptic drugs, and methods of neuropsychological evaluation. It is apparent that epilepsy is a multifaceted area: Psychologists not only can be of great assistance to patients with this condition, but may also learn a great deal from this complex disorder.

Differences in frequency of finger tremor in otherwise asymptomatic mercury workers.

Tremor was measured from the index finger during low force, position holding in 18 control subjects and 18 battery workers with low level exposure to mercury. All workers were asymptomatic on clinical neurological examination. No differences were found in average tremor amplitudes between the groups, but statistically significant abnormalities in tremor frequency distribution existed. Tremor power spectra in the group of mercury workers were shifted toward the higher frequencies and compressed into narrow frequency peaks. These results suggest that measurements of finger tremor that evaluate the frequency distribution can produce a higher diagnostic yield than traditional visual clinical judgement. The findings also confirm other reports that currently permitted exposures to mercury are associated with subtle but distinctive differences in tremor accompanying voluntary movement.

Use of demographic variables to predict full scale IQ: A replication and extension

The evaluation of current level of neuropsychological functioning is handicapped by the lack of validated actuarial methods for estimating premorbid intellectual functioning. The present study cross-validated and attempted to improve the one existing method of using demographic variables in a systematic way to predict WAIS Full Scale IQ (Wilson et al., 1978). A sample of 491 neurologically normal subjects was used. The results generally supported the IQ prediction equation, but did reveal systematic differences in accuracy of prediction and direction of prediction error for IQs in the high and low ranges. Also, a simpler IQ prediction formula that uses only years of education was developed and compared with the 5-variable Wilson et al. formula.

Comparison of preferred and nonpreferred hand performance on four neuropsychological motor tasks

Abstract This study explored the intermanual difference scores in 426 normal subjects on four neuropsychological tests, taking into consideration the effects of age, education, sex, and lateral preference. For the Finger Tapping Test and Hand Dynamometer measures, subjects who consistently demonstrated right lateral preference had greater intermanual differences than did left-handed subjects, while analyses on the Grooved Pegboard revealed that females tended to have larger percent difference scores than did males. Analyses on the fourth measure, the Tactual Performance Test (TPT), did not reveal differences related to lateral preference or sex. However, older and less well educated subjects tended not to improve from Trial 1 to Trial 2 of the TPT, possibly due to less efficient learning. These results suggest that interpretation of intermanual differences in neuropsychological assessment would benefit from consideration of demographic and lateral preference variables, in combinations that differ for spec...