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Biomedical subjects

C B Dodrill

Publications and source records attributed to C B Dodrill.

At least 19 recordsLinked to original sources
PubMed1999

Cognitive abilities and adjustment with gabapentin: results of a multisite study.

The cognitive and quality of life effects of gabapentin are not yet well explored. While preliminary work in the area has provided positive findings, a large double-blinded study has been needed to explore this area more thoroughly. From 24 sites in North America, 201 adults were studied who had uncontrolled complex partial seizures with or without secondary generalization. Attempts were made to convert each patient from one or two marketed antiepileptic drugs (AEDs) taken in baseline to gabapentin monotherapy (600, 1200, or 2400 mg/day). Tests of cognitive abilities and adjustment were administered at the end of the 8-week baseline period and at the end of the 26-week double-blind treatment period. Analyses of baseline to treatment period changes were conducted for each dose group in comparison with a reference group of placebo-treated patients from another study. In the area of cognitive functioning, no changes in any of the gabapentin groups were found in comparison with the reference group. In the area of adjustment and mood, however, improvement with gabapentin administration was noted on several variables pertaining to emotional and interpersonal adjustment. These results are consistent with findings from previous studies.

Acetates↗
PubMed1999

Myths of neuropsychology: further considerations.

The publication of "Myths of Neuropsychology" (Dodrill, 1997) has stimulated three responses, each of which takes issue with points in the original publication. These three responses especially address Myth #4 ("Above-average performances on neuropsychological tests are expected when intellectual abilities are above average") and to a lesser degree Myth #1 ("We have a good knowledge of the constructs that our tests measure"). The present paper reviews the thoughts and new data which these colleagues have provided in response to the original paper, and it also presents additional data bearing on the issues at hand. Based on the composite of information now available, it is conceded that Myth #4 was not accurately worded in the original paper. This was a mistake, and an alternate wording for Myth #4 is offered. Other changes in the original publication do not appear to be required. In order to resolve many of the issues at hand and thereby advance our profession, research in a number of areas is needed, many of which are specifically identified in the present paper.

Cognition↗
PubMed1998

What is the significance of subjective events recorded during long-term EEG video monitoring?

PURPOSE: Purely subjective events, identified as "seizures" by patients but not accompanied by any clinical or EEG changes, commonly occur during evaluation of patients for intractable epilepsy. We wished to determine the significance of such events. METHODS: We analyzed the frequency of subjective episodes in 379 adults who underwent EEG video monitoring as part of their evaluation for intractable epilepsy and the relationship of these experiences to epileptic and psychogenic nonepileptic (NES) seizures. We examined the results of tests of mental ability and of emotional, psychosocial, and quality of life (QOL) adjustment to determine if individuals with subjective events alone could be distinguished from those with epileptic seizures only, NES only, or no events, by these measures. RESULTS: We noted subjective events in 39% (147 of 379) of the patients. Of patients with subjective episodes, 52% also had epileptic seizures, 7% had NES, 1% had both epileptic seizures and NES, and 40% had subjective events alone. As a group, patients with subjective events alone were slightly more intelligent and less impaired neuropsychologically than people in the other groups, but they performed more poorly on several important measures of adjustment. CONCLUSIONS: The identification of persons with purely subjective episodes apart from all other episodes is important both phenomenologically and from a practical viewpoint.

Adolescent↗
PubMed1998

Effects of tiagabine monotherapy on abilities, adjustment, and mood.

PURPOSE: We evaluated the dose-related impacts of tiagabine (TGB) on cognition and mood in a monotherapy study. METHODS: Patients were 123 adults with uncontrolled partial seizures, each treated with a single currently available antiepileptic drug (AED) for management of clinical epilepsy. They completed a battery of neuropsychological tests during an 8-week prospective baseline period and once again at the end of the 12-week fixed-dose period (or earlier if they dropped out of the study). Sixty-six patients were randomized to 6 mg/day TGB and 57 were randomized to 36 mg/day TGB. RESULTS: Few changes in either abilities or adjustment and mood were noted when all patients were considered as a single group. However, analysis of both dose and attainment of TGB monotherapy showed that patients receiving TGB monotherapy did best, improving particularly in the areas of adjustment and mood with low-dose TGB and in the area of abilities with high-dose TGB. Patients who did not attain monotherapy showed no change except that the high-dose group did not perform as well on measures of mood and adjustment. Baseline AED and changes in seizure control did not affect the results. CONCLUSIONS: Patients' attainment of TGB monotherapy was associated with their achievement of positive changes of varying degree on psychological tests. Failure to attain TGB monotherapy was associated with no changes on the tests except in patients receiving high-dose TGB where it appeared that some alterations in mood might have been avoided if a slower titration schedule had been used.

Adolescent↗
PubMed1998

Is partial epilepsy progressive? Ten-year follow-up of EEG and neuropsychological changes in adults with partial seizures.

PURPOSE: This study was undertaken to determine what changes, if any, occur in the electroencephalogram (EEG) and in neuropsychological test findings of adults with medically intractable complex partial epilepsy over a 10-year period. METHODS: We studied 35 adults, with a mean age of 32 years (range, 16-59 years) at time of initial testing. We compared the distribution of epileptiform patterns documented on the initial pair of waking and sleeping EEGs to those observed on another pair obtained 10 years later. During this same 10-year period, we also examined changes in the Wechsler Adult Intelligence Scale (WAIS) and on the tests from the Neuropsychological Battery for Epilepsy. RESULTS: The EEGs of 28 (80%) of patients at the tenth year were identical to those seen initially. Five (14%) of patients demonstrated EEGs after 10 years with either no discharges or only unilateral discharges, where bilateral discharges were seen a decade earlier. Only two (6%) of patients had EEGs at the tenth year that showed bilateral discharges where only unilateral discharges were seen originally. We found no general change in intelligence or neuropsychological functioning after 10 years, although a few subtle losses were noted on several neuropsychological measures. CONCLUSIONS: For most adults with medically intractable complex partial epilepsy, the EEG and neuropsychological test scores remain reasonably stable over a decade.

Adolescent↗
PubMed1997

Reading errors following right hemisphere injection of sodium amobarbital.

The role of the nondominant hemisphere in reading is controversial. We characterized the reading errors made by 64 right-handed adults with complex partial seizures (half with seizure foci on the right and half on the left), after right hemisphere injection of sodium amobarbital. Subjects were presented with 20 six-word sentences and all were found to have speech associated with the left hemisphere only. A variety of reading errors occurred, most of which fell under the syndrome of "neglect dyslexia" including deletions and substitutions of whole words on the left side of a line of text as well as within-word neglect errors. The nature of these errors indicated that they may have been caused by an interaction between a peripheral processing deficit and more centrally located conceptual knowledge of linguistic structure. Other errors could be attributed to a general decrease in attentional mechanisms. Neglect errors at the level of the sentence occurred in the absence of neglect errors at the level of the word although the converse was not true. This suggests that the latter may represent a more severe deficit in the mechanism that causes the former. A double dissociation existed between single word neglect dyslexia errors and "visual" errors, indicating separate processing mechanisms.

Adult↗
PubMed1997

An exploratory comparison of three methods of memory assessment with the intracarotid amobarbital procedure.

This paper has two objectives. The first is to compare three methods of amobarbital memory assessment in 172 adults prior to epilepsy surgery. The three methods are significantly different from one another and there was only a moderate degree of concordance between them; concordance depended upon the method, the side of surgery, and the side of speech. The second objective of the paper is to evaluate the relative abilities of the methods of differentiate, prior to surgery, patients who did and who did not suffer mild to moderate postoperative losses in verbal memory following surgery. To meet this objective a subsample of patients was selected based on the presence or absence of this type of memory loss. Significant differences in the ability of the amobarbital methods to identify the patients at risk for postoperative memory loss were observed, with the method assessing recall memory during drug presence having the best prediction rate.

Adult↗
PubMed1997

Cognitive and quality of life effects of differing dosages of tiagabine in epilepsy.

Tiagabine blocks the uptake by neurons or glia of synaptically released GABA resulting in prolonged GABAergic activity and decreased likelihood of epileptic seizures. We evaluated the cognitive and quality of life effects of tiagabine in a double-blind, add-on, placebo-controlled, parallel, multicenter, dose-response efficacy study in patients with focal epilepsy whose complex partial seizures were difficult to control. One hundred sixty-two patients provided cognitive and quality of life data for the analyses and received the following treatments: placebo (n = 57), 16 mg/d tiagabine (n = 34), 32 mg/d tiagabine (n = 45), or 56 mg/d tiagabine (n = 26) at a fixed-dose for 12 weeks after a 4-week dose titration period. Eight cognitive tests and three measures of mood and adjustment were administered during the baseline period and again during the double-blind period near the end of treatment (or at the time of dropout). The patient groups were similar at entry into the study. Results showed no clinically important changes with the addition of tiagabine on the test battery. Although this is an encouraging finding, it remains for future investigations to determine the cognitive and behavioral effects of tiagabine either as monotherapy or in relation to other antiepileptic drugs.

Adolescent↗
PubMed1997

Outcome following surgery in patients with bitemporal interictal epileptiform patterns.

We reviewed outcome at least 1 year after temporal lobectomy in 44 patients with bitemporal, independent, interictal epileptiform patterns on EEG. All 44 underwent preoperative intracranial monitoring. Twenty-two (50%) were seizure-free, 14 (32%) had at a least 75% reduction in seizures, and eight (18%) had less than a 75% reduction in seizures. We analyzed age of seizure onset, duration of epilepsy, gender, side of operation, history and clinical findings, findings on MRI, results of intracranial EEG-video monitoring, presence or absence of lateralizing neuropsychological deficits, and pathology of resected tissue to identify factors associated with outcome. Three factors emerged as independently associated with a good outcome: concordance of MRI abnormality and side of operation (p = 0.01), history of febrile seizures (p = 0.04), and 100% lateralization of intracranially recorded ictal onsets to the side of operation (p = 0.05). A seizure-free outcome was much more likely to occur if more than one of these factors was present: with at least two factors co-existing, 83% (15/18) of patients were seizure-free, while only 35% (7/20) were seizure-free with a single factor present (p = 0.0009). Of the six patients without any of the three factors, none were seizure-free. We conclude that it is possible to predict reasonably which patients with bitemporal epileptiform abnormalities will have a good outcome after surgery.

Adolescent↗
PubMed1996

Unilateral focal preponderance of interictal epileptiform discharges as a predictor of seizure origin.

OBJECTIVE: To test the hypothesis that seizure origin may be predicted from scalp-recorded electroencephalographic interictal epileptiform patterns that occur exclusively or preponderantly over a single focal region. PATIENTS AND METHODS: Fifty-nine of 98 patients (>=16 years old) with intractable epilepsy who underwent sphenoidal/scalp electroencephalographic video monitoring were identified as having interictal epileptiform discharges preponderantly (>=75% of all discharges) or exclusively over a single unilateral region (basal-temporal, midposterior temporal, frontopolar, superior frontal, central). Ictal recordings in 48 patients could be interpreted as demonstrating focal origins, and the ictal findings were compared with the interictal findings. Eleven patients had uninterpretable ictal recordings or no seizures during monitoring and were not further considered. RESULTS: All seizures arose from the expected region in 39 of the 48 patients (Fisher's exact test, P<.001). Interictal discharges occurred exclusively over a single region in 23 of the 48 patients, and all seizures arose from the expected region in 22 of the 23 patients (P<.001). Seventeen patients among this group of 23 had exclusively unilateral basal-temporal discharges, and all seizures arose from the expected side, with the exception of one seizure that arose from the opposite side in one patient, with her other seizure arising from the expected side (P<.001). All seizures arose from the expected region in three patients who exhibited all interictal discharges arising from a single superior frontal region, in two patients with discharges only over a single midposterior temporal region, and in one patient with exclusively unilateral frontopolar discharges. CONCLUSIONS: Interictal discharges that demonstrate a consistent unilateral focal preponderance over a single region, regardless of location, generally predict seizure origin. If the discharges are exclusive to a single region, there is a greater than 95% probability that all recorded seizures will originate from the expected region.

Adolescent↗
PubMed1996

Epilepsy.

Explore the source record for details and available documents.

Affect↗
PubMed1996

Five-year outcome after epilepsy surgery in nonmonitored and monitored surgical candidates.

PURPOSE: We wished to compare outcome 5 years after temporal lobectomy in 28 patients selected for surgery on the basis of interictal EEG patterns with that in 46 patients who underwent EEG-video monitoring studies as part of their preoperative evaluation during the same era. METHODS: The 28 nonmonitored patients had interictal EEG patterns that demonstrated a consistent, unilateral, anterior-midtemporal epileptiform focus, without discordant findings from other studies. Outcomes were assessed for years 4 and 5 after operation. RESULTS: Twenty-six of 28 (92.9%) nonmonitored patients were seizure-free or had at least 75% reduction in seizures. Twenty-nine of 46 (63.0%) monitored patients were seizure-free or had at least 75% reduction in seizures. Preoperative interictal EEGs of 29 of these patients showed independently localized bitemporal, extratemporal, midposterior temporal, or diffuse epileptiform patterns. The remaining 17 monitored patients had preoperative strictly unilateral anterior-midtemporal interictal discharges, and their outcome was comparable to the nonmonitored group, with 15 (88.8%) seizure-free or with at least 75% reduction in seizures. CONCLUSIONS: A proportion of candidates for epilepsy surgery can be selected without ictal recordings provided that interictal EEGs demonstrate consistent unilateral anterior-midtemporal epileptiform discharges and that other data are not discordant.

Adolescent↗
PubMed1995

Effects of differing dosages of vigabatrin (Sabril) on cognitive abilities and quality of life in epilepsy.

Vigabatrin (VGB) prevents seizures by irreversible inhibition of gamma-aminobutyric acid (GABA) transaminase and a resulting increase in GABA levels. We evaluated the cognitive and quality-of-life (QOL) effects of VGB in a double-blinded, add-on, placebo-controlled, parallel group dose-response study of patients with focal epilepsy whose complex partial seizures (CPS) were difficult to control. In a single investigation, patients were randomly assigned to placebo (n = 40), 1 g VGB (n = 36), 3 g VGB (n = 38), or 6 g VGB (n = 32), treated for 12 weeks after a 6-week dose escalation period, and tested at the end of the baseline period and at the end of the treatment period with eight cognitive measures and three tests of mood and adjustment. The patient groups were highly similar at study entry. Results at the end of the study showed substantial relief from seizures. The Digit Cancellation Test showed decreases in performance with increasing doses of VGB. Performance on no other test showed any decrement with increasing dosage. Relief from seizures was not associated with changes on the psychological tests. VGB is a useful antiepileptic drug (AED) that has little impact on tests of either cognitive abilities or QOL, even at a high dose.

Adolescent↗
PubMed1994

Epilepsy surgery: non-invasive versus invasive focus localization. What is needed from a neuropsychological point of view.

This article discusses the neuropsychological aspects of surgery for epilepsy, and what is needed in EEG evaluation to permit the best use of neuropsychological data to help identify the most promising surgical candidates. Neuropsychological changes after surgery are first discussed, and it is noted that changes in memory are most important with less important fluctuations in intelligence and language and with other areas showing few or no changes. Emotional and psychosocial outcomes of surgery are dependent upon relief from seizures, with substantial relief being essential for improvement to be observed. Finally, it is noted that a combination of EEG and neuropsychological variables results in the best prediction of seizure relief, but reliable EEG data are critical to this effort. Obtaining such data frequently necessitates EEG monitoring, frequently with invasive electrodes. Such information often provides the clearest information and the best chance of assisting patients with epilepsy.

Brain↗
PubMed1993

Reliability of the Lateral Dominance Examination.

The reliability of the Lateral Dominance Examination over a 5-year period was evaluated in 162 normal and neurologically impaired adults. Stability of individual test items was appraised as well as that of summary measures of handedness, eyedness, and footedness. Items evaluating handedness rendered highly consistent results with the most reliable item relating to hand used for writing (100%). Eyedness and footedness items were somewhat less reliable. While the data raised the possibility that non-right-handers may be slightly less consistent over time, membership in a neurological group, extent of impairment on neuropsychological tests, and gender were unrelated to consistency in lateral preference measurement. It is concluded that the Lateral Dominance Examination is a reliable measure of lateral preference.

Adolescent↗
PubMed1993

Evaluation of the effects of vigabatrin on cognitive abilities and quality of life in epilepsy.

We evaluated the psychological effects of the antiepilepsy drug vigabatrin in a randomized multicenter double-blind placebo-controlled parallel group study that compared 3 grams oral vigabatrin with placebo as daily add-on therapy in patients with focal epilepsy whose complex partial seizures were difficult to control. Testing at baseline and after 12 weeks of vigabatrin (n = 83) or placebo (n = 85) used eight measures of cognitive abilities and three of mood and adjustment. The vigabatrin and placebo groups were highly similar at entry into the study. At the end of the study, there were no differences between the vigabatrin and placebo groups on any cognitive variable or on any measure of mood and adjustment. Analysis of the results related to relief from seizures demonstrated only chance findings. In a similar manner, there were no relationships between vigabatrin serum levels at the end of the study and changes on measures of abilities and adjustment. Vigabatrin appears to be a useful antiepilepsy drug with little impact upon tests of either cognitive abilities or quality of life.

Adaptation, Psychological↗