Carl B. Dodrill

A neuropsychological battery for epilepsy.

The development of the Neuropsychological Battery for Epilepsy is presented. The tests are designed to be helpful in the evaluation of adult epileptics. The battery consists of General Measures which include tests in the areas of intellectual functioning, emotional status, and lateral dominance. The development of a series of 16 Discriminative Measures is presented in detail through the discussion of a pilot study, the principal investigation, and a cross‐valida‐tional effort. In the principal study, 50 epileptics were individually paired with individuals having no history of neurological disease, and their performances on a wide range of ability measures were compared. Tests were eliminated if they did not appear sensitive to the brain‐related problems of epileptics, if they demonstrated excessive duplication with other measures, or if they did not cross‐validate with a new sample of 25 epileptic–normal pairs. The advantages of the battery were discussed, including coverage of areas previously not adequately assessed, elimination of tests with limited utility, greater uniformity and accuracy in the classification of individual subjects, and standardization of the tests with epileptics.

An Objective Method for the Assessment of Psychological and Social Problems Among Epileptics

Summary: Numerous investigators have identified psychological and social problems among epileptics and in many instances these appear to be more debilitating than the seizures themselves. However, assessment of these problems has most frequently been done by subjective means and when objective tests have been used, they were almost always developed for and standardized on populations other than epileptics. The development of the Washington Psychosocial Seizure Inventory (WPSI) is presented in this paper. After pilot work, 127 adult epileptics were evaluated for psychosocial problems and they completed the 132‐item Inventory. Professional assessment of difficulties was made with respect to family background, emotional adjustment, interpersonal adjustment, vocational adjustment, financial status, adjustment to seizures, and medical management. Finally, an assessment of overall psychosocial functioning was made. Through an item‐by‐item correlation technique, scales were empirically developed for each of these areas and a profile was produced which gives both the absolute and the relative extents of difficulties for each patient with respect to each area. Potential applications for the WPSI are presented.

Neuropsychological Abilities of Children with Epilepsy

Summary: One hundred eighteen epileptic children, aged 6–15 years, underwent detailed neuropsychological testing including the Wechsler Intelligence Scale for Children‐Revised and the age‐appropriate Halstead‐Reitan battery. Eight had classical absence seizures only, eight had classic absence seizures and generalized tonic‐clonic seizures, 30 had generalized tonic‐clonic seizures only, 31 had partial seizures only, 20 had partial seizures and generalized seizures, 15 had atypical absence seizures, and five had minor motor seizures. A control group of 100 children without seizures, matched to the general population for intelligence and matched to the seizure cases for age, underwent identical testing. The Wechsler full‐scale intelligence quotient (FSIQ) of cases was significantly (p = 0.01) lower than that of controls and was related to seizure type. Children with minor motor or atypical absence seizures had the lowest average FSIQ (70 and 74, respectively). All seizure types were associated with below‐control intelligence except classic absence only. Intelligence was also correlated with degree of seizure control. A highly significant inverse correlation between years with seizures and intelligence was found (p < 0.0001). A rating of neuropsychological impairment, derived from all measures of brain function, was assigned to each child. Epileptic children had significantly more impairment than controls (p < 0.0001). Children with seizures had been placed in special education or had repeated a grade in school almost twice as frequently as controls (p < 0.001). Even though often placed in a class of younger children, their academic achievement was behind grade placement more often than in controls. Children with seizures differed significantly from controls in making more errors on language‐related tasks.

Correlates of Generalized Tonic‐Clonic Seizures with Intellectual, Neuropsychological, Emotional, and Social Function in Patients with Epilepsy

Summary: Relationships between generalized tonic‐clonic seizures and indicators of psychological functioning were evaluated in 94 adults with epilepsy who had exceptionally clear seizure histories. Patients were divided according to lifetime numbers of attacks and the presence or absence of a history of major motor status epilepticus. History of status epilepticus or history of more than 100 individual convulsions was associated with decreased functioning in all areas. Abilities were poorest for the group with a history of status, whereas emotional and psychosocial adjustment were worst in persons having large numbers of single convulsions. Possible reasons for the decreased test scores other than seizures were explored in great detail, but none could account for the differences in performance across the groups.

Psychotropic effects of carbamazepine in epilepsy A double‐blind comparison with phenytoin

The “psychotropic” effects of carbamazepine were evaluated with phenytoin (Dilantin) as reference agent in a counterbalanced, crossover study. Forty adult epileptics were given a series of neuropsychologic tests and the MMPl after 4 months on each agent. Most abilities were much the same with either anticonvulsant, but there were fewer errors with carbamazepine on mental tasks requiring attention and problem solving, and some improvement in emotional status was suggested. The findings were consistent with patient reports of improvement in alertness and mental functioning. These results combine with the excellent anticonvulsant properties of carbamazepine to support its use as an anticonvulsant.

Neuropsychological effects of seizures.

The neuropsychological effects of seizures, including an accumulation of single attacks, on mental abilities are explored through a selective review of the worlds literature. Each paper included in this review was longitudinal in nature, and in each case, formal psychological testing was accomplished both at the beginning and at the end of the study. Of the 22 investigations meeting all requirements for inclusion, 9 focused on children and 13 on adolescents and adults. Some difficulties were encountered in that the types and numbers of seizures occurring during the studies were rarely included. Except in three studies where there were very few seizures of any kind, it appears justifiable to assume that the patients in all other studies had active seizure disorders. Assuming this to be true, in 12 of the remaining 20 papers, a relationship was found between seizures and changes in mental abilities, in 5 cases the results were mixed or uncertain, and in 3 cases the available evidence was against such a relationship. Mild but definite relationships between seizures and mental decline are supported by this literature review, but these relationships require much more study, particularly with a clearer understanding of the types and frequencies of seizures experienced. Suggestions for future research are offered.

Intensive EEG Monitoring and Psychological Studies of Patients with Pseudoepileptic Seizures

Summary: EEG/closed‐circuit television long‐term monitoring was used as a definitive diagnostic tool to identify and characterize 25 patients with pseudoepileptic seizures and a similar group of subjects with epilepsy, confirming the value of the procedure. The groups did not differ with respect to intelligence, neuropsychological impairment, or incidence of potential etiological factors for seizures. Scores on the Minnesota Multiphasic Personality Inventory (MMPI) and the Hypochondriasis, Hysteria, and Schizophrenia Scales were significantly higher for the pseudoepileptic group than for the other subjects. As a whole, the former patients exhibited an MMPI profile pattern frequently seen in the conversion form of hysteria. A set of three rules derived from the MMPI profiles was used to classify the patients correctly in 80–90% of cases. As evaluated by the Washington Psychosocial Seizure Inventory, psychosocial problems of patients with pseudoepileptic seizures were more severe in certain areas, and appeared to reflect early family background problems and inappropriate management of their disorders.

Effects of Vagal Nerve Stimulation on Cognition and Quality of Life in Epilepsy

To evaluate the cognitive and quality-of-life (QOL) impacts of vagal nerve stimulation (VNS), 160 patients with uncontrolled partial seizures from 20 sites were enrolled in a double-blind study. Patients were randomly assigned to low (minimal) stimulation (n = 82) or high (now clinically used) stimulation (n = 78) conditions and given a group of cognitive and QOL tests before implantation and after 12-16 weeks of VNS treatment. Results showed no clear cognitive changes. However, fewer emotional and physical problems were reported by the High Group than the Low Group at the end of the study. The 32 patients who had at least 50% seizure relief showed slightly more improvement in QOL variables than those patients who did not demonstrate this degree of seizure reduction. Overall, a small number of favorable QOL but no cognitive changes were associated with levels of VNS stimulation that are now typically used clinically.

Progressive cognitive decline in adolescents and adults with epilepsy

The effects of an accumulation of single seizures upon mental abilities in adolescents and adults is explored through a selective review of the worlds literature. The papers reviewed were divided up into cross-sectional and longitudinal studies. Of 16 investigations meeting all requirements for inclusion, 12 produced results pointing to a relationship between seizures and adverse cognitive change. The cross-sectional studies produced stronger results than the longitudinal ones, no doubt because the effects of co-existing factors not related to seizure effects were included in measures of cognitive decline. The longitudinal investigations showed mild but definite relationships between seizures and mental decline. However, relationships could be found only with generalized tonic-clonic seizures and not with partial attacks. Results of an original investigation were reported which were consistent with the literature review. Suggestions for future research were offered.

Zonisamide in epilepsy: a pilot study.

Summary: We compared zonisamide monotherapy (12 weeks) to carbamazepine monotherapy (12 Weeks) after phenytoin baseline monotherapy (8 weeks) in an open crossover pilot study of eight adults with uncontrolled partial seizures. Zonisamide had definite antiepilepitic activity in five subjects. In two of these, response to zonisamide was superior to that to either phenytoin or carbamazepine. A third subject became seizure free on zonisamide, but had to be withdrawn after 18 days because of mild stevens‐Johnson syndrome. The other three subjects were withdrawn from the study because of drug toxicity, manifested mainly by impaired higher mental function and increased seizures. The best response to zonisamide was at doses approximating 6 mg/kg/day, with plasma levels of 20–30 mg/L. Plasma levels of > 30 mg/L usually were associated with toxicity. the pharmacokinetics of zonisamide are complex and nonlinear, with steady‐state plasma levels being approximately three times higher than those predicted from a singledose study.