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Biomedical subjects

M L Prevey

Publications and source records attributed to M L Prevey.

10 recordsLinked to original sources
PubMed1998

Complex partial and secondarily generalized seizure patients: cognitive functioning prior to treatment with antiepileptic medication. VA Epilepsy Cooperative Study 264 Group.

This investigation of cognitive functioning in patients with symptomatic localization-related (partial) epilepsy prior to administration of antiepileptic medication is part of a nationwide prospective, double-blind study of drug efficacy and longitudinal changes in cognition associated with seizure disorders. Recently-diagnosed patients with complex partial or secondarily generalized tonic clonic seizures, equated for age, education and IQ, were compared with normal controls on a battery of neuropsychological tests: verbal and figural memory measures (Rey auditory verbal learning test, Rey Osterrieth complex figure), and a brief behavioral toxicity battery comprising measures of motor function, concentration and mental flexibility (Lafayette grooved pegboard, controlled word association test, Stroop, paced auditory serial addition test [PASAT]). Control subjects perform significantly better than both groups of seizure patients on several measures of motor speed/integration and memory, specifically the pegboard and the RAVLT learning (3-5) and recall trials. Secondarily generalized seizure patients show greatest impairment. They perform significantly worse than patients with complex partial seizures and control subjects on the controlled word association test and the most demanding Stroop color word trial, both measures of concentration and mental flexibility. These findings document deficits in memory as well as concentration and motor function in complex partial and in secondarily generalized seizure patients prior to treatment with antiepileptic medication.

Adult↗
PubMed1996

Effect of valproate on cognitive functioning. Comparison with carbamazepine. The Department of Veterans Affairs Epilepsy Cooperative Study 264 Group.

OBJECTIVE: To assess the effects of carbamazepine vs valproate sodium on cognitive functioning in patients with epilepsy compared with normal control subjects. DESIGN: Patients with recently diagnosed, previously unmedicated seizures participated in a prospective randomized double-blind Department of Veterans Affairs multicenter study of the efficacy and toxicity of carbamazepine vs valproate. MAIN OUTCOME MEASURE: A behavioral toxicity battery was administered prior to treatment and again 6 and 12 months after the initiation of antiepileptic medication. RESULTS: There were no significant differences in the effect of carbamazepine vs valproate on motor speed and coordination, memory, or concentration and mental flexibility, and there was no significant decline in neuropsychological performance from pretreatment baseline levels for either drug. No significant differences in performance were found between patients with low (mean, 52.8 micrograms/mL) vs high (mean, 94.4 micrograms/mL) serum valproate levels within the therapeutic range. Patients treated with either carbamazepine or valproate did not show practice effects experienced by normal controls, a finding that may reflect a subtle compromise in cognitive functioning. CONCLUSION: The impact of carbamazepine and valproate monotherapy on cognitive functioning is similar: both drugs produce minimal negative effects compared with pretreatment baseline performance.

Adult↗
PubMed1992

Test-retest comparability and control subject data for the Rey-Auditory Verbal Learning Test and Rey-Osterrieth/Taylor Complex Figures.

This report presents data from a nonpatient sample considering the test-retest reliability and task comparability of the Rey-Osterrieth/Taylor Complex Figures and the Rey Auditory Verbal Learning Test. These tasks were presented to normal comparison subjects as a component of a large Department of Veterans Affairs Cooperative Study on anticonvulsant effects in a manner typical of routine clinical use. The results suggest a high degree of reliability for the Rey-Auditory Verbal Learning Test, supporting its use for test-retest situations. However, cautions are discussed for the use of the Rey-Osterrieth-Taylor Complex Figure comparisons.

Journal Article↗
PubMed1991

Feeling-of-knowing in temporal lobe epilepsy: monitoring knowledge inaccessible to conscious recall.

Feeling-of-Knowing was compared in left temporal, right temporal, and control subjects. Seizure patients, like controls, demonstrate knowledge of information that is not accessible to conscious recall, but they are less accurate in FOK judgements. Furthermore, there are significant differences between seizure patients and controls in the relationship between Feeling-of-Knowing and object level memory scores: (1) Controls spend more time searching memory for inaccessible information that is correctly identified on a later recognition test than they do for information that is incorrectly recognized. (2) Latency of correct recognition decreases as strength of FOK increases among controls, suggesting that controls correctly anticipate the outcome of memory search. These patterns of performance, which are consistent with an efficient memory search termination device, were not observed among seizure patients. The findings suggest that inaccurate Feeling-of-Knowing may play a role in inefficient memory search mechanisms in temporal lobe epilepsy.

Adult↗
PubMed1991

A method of assessing the efficacy of memory rehabilitation techniques using a "real-world" memory task: learning a computer language.

A software program developed to assess the effectiveness of memory rehabilitation techniques is described. This project addresses current weaknesses in the research literature on memory rehabilitation: 1) remediation strategies are evaluated in terms of performance on a practical, real-world memory task, rather than a laboratory learning task; 2) the program allows maximum flexibility in assessing a wide variety of remediation strategies and training schedules; and, 3) the software, which provides sensitive outcome measures and detailed feedback about performance, is adaptable to the needs of patients with widely varying degrees of memory impairment. The results of a demonstration project are included to illustrate the use of this technology in determining the usefulness of different mnemonic strategies for patients with specific patterns of memory deficit. The importance of assessing maintenance of rehabilitation training over time is stressed.

Computer Graphics↗
PubMed1989

How often is medication taken as prescribed? A novel assessment technique.

The evaluation of the efficacy of medication is confounded when patients do not adhere to prescribed regimens. Overdosing, underdosing, and erratic dosing intervals can diminish drug action or cause adverse effects. Using a new method with epilepsy as a model, we assessed compliance with long-term medications among newly treated and long-term patients. Medication Event Monitor Systems (Aprex Corporation, Fremont, Calif) are standard pill bottles with micro-processors in the cap to record every bottle opening as a presumptive dose. Compliance rates averaged 76% during 3428 days observed: 87% of the once daily, 81% of the twice daily, 77% of the three times a day, and 39% of the four times a day dosages were taken as prescribed. Coefficients of variation of drug serum concentrations had no significant relationship to compliance rates. Pill counts overestimated compliance increasingly as compliance with the prescribed regimen declined. Neither drug serum concentrations nor pill counts would have identified the frequency of missed doses that were revealed with continuous dose observations.

Adult↗
PubMed1988

Metamemory in temporal lobe epilepsy: self-monitoring of memory functions.

Temporal lobe seizure patients and control subjects participated in an investigation of metamemory. The two-part study explored the individual's perception of memory abilities for both encoding and retrieval. Experiment I addressed self-monitoring of encoding through a study of prediction of memory span. Experiment II explored self-monitoring of retrieval through a study of "Feeling of Knowing." The results indicate that left and right temporal lobe seizure patients tend to overestimate their memory capacities, in comparison with normal controls, and that self-monitoring tends to be less accurate for material (verbal or nonverbal) mediated by side of lesion. The potential impact of inaccurate memory monitoring on the memory dysfunction observed in seizure patients is discussed.

Adult↗
PubMed1988

Gist recall in temporal lobe seizure patients (a study of adaptive memory skills).

This study investigates the capacity of lateralized temporal lobe seizure patients to process and retain complex narrative information, to recall the most important elements of verbal material, and to make effective use of mnemonic strategies during a brief study period to improve performance. Compared to normal controls, both left and right temporal lobe samples recall significantly less information on both immediate and post-study trials. In addition seizure patients, particularly left temporal subjects, engaged in fewer active learning strategies and produced more instances of major distortion. However, despite their reduced efficiency in total recall, seizure patients, like control subjects, do tend to remember a higher proportion of important idea units and a smaller proportion of details. The findings are discussed in relation to previous research which documented memory monitoring failures in temporal lobe seizure patients, and in terms of the development of adaptive memory skills to circumvent memory deficits.

Adaptation, Psychological↗
PubMed1986

Short term retention with lateralized temporal lobe epilepsy.

This investigation focused upon whether individuals with lateralized temporal-lobe epilepsy have impairments in short term memory and, if so, whether these impairments are of a material-specific nature. The Peterson short term memory distractor paradigm which consists of single, brief presentations of stimuli with varying decay intervals and appropriate interpolated distractors was employed. A significant deficit in both left and right temporal lobe seizure groups was documented in comparison to controls for verbal but not for non-verbal materials. The results suggest that one aspect of the memory problem observed in temporal lobe seizure patients relates to relatively early components of information processing where encoding is primarily based upon physical rather than semantic characteristics of the stimulus and material-specificity is less evident.

Adolescent↗