Richard I. Naugle

Prediction of cognitive change as a function of preoperative ability status among temporal lobectomy patients seen at 6‐month follow‐up

The relationship between preoperative ability levels and postoperative changes in cognitive function was examined among 23 left (LTL) and 19 right (RTL) temporal lobectomy patients using a battery of memory, language, and visuospatial tasks administered approximately 3 months before surgery and at 6 months follow-up. Higher preoperative performances on the memory and language measures were associated with larger decrements in postsurgical scores among the LTL patients. The RTL group showed no consistent relationship between preoperative ability levels and subsequent postsurgical cognitive changes. Based on the present data, we constructed baserate tables for the Wechsler Memory Scale-Revised indicating the likelihood of measurable gains or losses in memory as a function of presurgical ability level for patients undergoing LTL. While tentative, these data provide a useful and practical guide for counseling prospective epilepsy patients of the attendant cognitive risks of LTL.

Extent of resection in temporal lobectomy for epilepsy. II. Memory changes and neurologic complications

Summary: We present correlations of extent of temporal lobectomy for intractable epilepsy with postoperative memory changes (20 cases) and abnormalities of visual field and neurologic examination (45 cases). Postoperative magnetic resonance imaging (MRI) in the coronal plane was used to quantify anteroposterior extent of resection of various quadrants of the temporal lobe, using a 20‐compartment model of that structure. The Wechsler Memory Scale‐Revised (WMS‐R) was administered pre‐operatively and postoperatively. Postoperative decrease in percentage of retention of verbal material correlated with extent of medial resection of left temporal lobe, whereas decrease in percentage of retention of visual material correlated with extent of medial resection of right temporal lobe. These correlations approached but did not reach statistical significance. Extent of resection correlated significantly with the presence of visual field defect on perimetry testing but not with severity, denseness, or congruity of the defect. There was no correlation between postoperative dysphasia and extent of resection in any quadrant. Assessment of extent of resection after temporal lobectomy allows a rational interpretation of postoperative neurologic deficits in light of functional anatomy of the temporal lobe.

Intracarotid amobarbital procedure as a predictor of material-specific memory change after anterior temporal lobectomy.

Summary: Memory testing during the intracarotid amobarbital procedure (IAP) is used extensively to identify temporal lobe surgery candidates “at risk” for developing severe postoperative anterograde amnesia. However, the utility of the IAP in predicting commonly observed material‐specific memory deficits has not been thoroughly investigated. We examined the utility of contralateral IAP memory testing, as an index of the functional capacity of the surgical temporal lobe, to predict postoperative material‐specific memory changes on the Wechsler Memory Scale‐Revised (WMS‐R) in patients with left hemisphere speech dominance undergoing left (n = 32) and right (n = 31) temporal lobectomy (TL). Left TL patients who “passed” contralateral IAP memory testing (368% recognition of memory items) had significantly greater verbal memory decrements than those who “failed” the IAP, presumably as a result of removal of functional tissue. A similar relationship between contralateral IAP performance and visual memory performance was not observed among right TL patients. Thus, the functional adequacy of the tissue to be resected appears to be inversely related to postoperative verbal memory decrement, at least among left TL patients. This relationship is consistent with results of recent studies demonstrating an inverse relationship between verbal memory decrements after left TL and preoperative neuropsychological verbal memory performance, magnetic resonance imaging (MRI) hippocampal volumes, and degree of mesiotemporal sclerosis (MTS).

Intracarotid amobarbital procedure: I. Prediction of decreased modality-specific memory scores after temporal lobectomy.

Summary: To assess predictive value of the intracarotid amobarbital procedure (IAP) for decreased postoperative modality‐specific memory, we studied 37 temporal lobectomy patients with intractable partial epilepsy who were selected for operation independent of preoperative IAP findings. When ipsilateral IAP failure was defined by an absolute method as a retention score <67%, the results were not associated with decreased modality‐specific memory after operation. When ipsilateral IAP failure was defined by a comparative method as a retention score at least 20% lower after ipsilateral than contralateral injection, the results showed greater differences between groups, but differences still did not achieve statistical significance. Four left‐resection patients who failed the ipsilateral IAP had a median postoperative change in the Wechsler Memory Scale‐Revised (WMS‐R) Verbal Memory Index score of ‐14%, whereas 16 left‐resection patients who passed the ipsilateral IAP had a mean postoperative change in the WMS‐R Verbal Memory Index score of ‐7.5% (p = 0.12). These results suggested that the IAP interpreted comparatively may be a helpful adjunctive test in assessment of relative risk for modality‐specific memory dysfunction after temporal lobectomy, but larger series of operated patients are needed to confirm this possibility. In this series, complete amnesia was not noted after ipsilateral injection, even in patients with postoperative modality‐specific memory decline.

Intracarotid Amobarbital Procedure: II. Lateralizing Value in Evaluation for Temporal Lobectomy

Summary: The intracarotid amobarbital procedure (IAP) was assessed for lateralizing value in 37 patients who later had temporal lobectomy for intractable epilepsy. Among patients who failed IAP memory testing on one side (defined as a retention score for test items at least 20% lower on one side than the other), significantly more patients failed the injection contralateral (16 of 20, 80%) than ip‐silateral (4 of 20, 20%) to the side of later resection (p = 0.008). In addition, preoperative EEG evidence of bilateral temporal epileptogenicity was significantly more frequent among patients who failed the ipsilateral IAP injection (2 of 4, 50%) than among patients who passed the ipsilateral IAP injection (2 of 33, 6%) (p = 0.050). Finally, failure of the contralateral IAP injection involved significantly more severe amnesia for test items (median retention score 25%) than did failure of the ipsilateral injection (median retention score 59%) (p = 0.047). Profoundly low retention scores <33% occurred only with contralateral injection. These findings suggest that the IAP has some adjunctive lateralizing value for the epileptogenic hemisphere in patients with temporal lobe epilepsy, especially when the retention score with one injection is profoundly low.

The latent structure of attention-deficit/hyperactivity disorder in a clinic-referred sample

The question of whether attention-deficit/hyperactivity disorder (ADHD) represents a continuum of attentional and executive dysfunction or a natural category has yet to be extensively investigated. Subjective report and neuropsychological data from 437 individuals referred for neuropsychological evaluation were analyzed using latent class and taxometric analyses (mean above minus below a cut [MAMBAC], maximum eigenvalue [MAXEIG], and latent mode [LMODE]). Results indicated no significant evidence for a taxonic representation of ADHD across multiple procedures and indicator sets. Similarly, there was no evidence that ADHD subtypes represent a qualitative distinction. These findings may suggest that current diagnostic conceptualizations are inadequate for accurately identifying and characterizing individuals with problems related to attention and executive dysfunction. Alternatively, the null findings may have resulted from inadequate indicator selection. A dimensional model may better facilitate accurate identification of individuals at risk for functional impairment.

Evaluating the Contributions of State of the Art Assessment Techniques to Predicting Memory Outcome after Unilateral Anterior Temporal Lobectomy

Summary:  Purpose: Although anterior temporal lobectomy (ATL) is an effective treatment for many patients with medically refractory temporal lobe epilepsy (TLE), one risk associated with this procedure is postsurgical decline in memory. A substantial number of past studies examined factors that predict memory decline after surgery, but few have investigated multiple predictors simultaneously or considered measures that are currently in use.

Computerized Neuropsychological Assessment Devices: Joint Position Paper of the American Academy of Clinical Neuropsychology and the National Academy of Neuropsychology

This joint position paper of the American Academy of Clinical Neuropsychology and the National Academy of Neuropsychology sets forth our position on appropriate standards and conventions for computerized neuropsychological assessment devices (CNADs). In this paper, we first define CNADs and distinguish them from examiner-administered neuropsychological instruments. We then set forth position statements on eight key issues relevant to the development and use of CNADs in the healthcare setting. These statements address (a) device marketing and performance claims made by developers of CNADs; (b) issues involved in appropriate end-users for administration and interpretation of CNADs; (c) technical (hardware/software/firmware) issues; (d) privacy, data security, identity verification, and testing environment; (e) psychometric development issues, especially reliability, and validity; (f) cultural, experiential, and disability factors affecting examinee interaction with CNADs; (g) use of computerized testing and reporting services; and (h) the need for checks on response validity and effort in the CNAD environment. This paper is intended to provide guidance for test developers and users of CNADs that will promote accurate and appropriate use of computerized tests in a way that maximizes clinical utility and minimizes risks of misuse. The positions taken in this paper are put forth with an eye toward balancing the need to make validated CNADs accessible to otherwise underserved patients with the need to ensure that such tests are developed and utilized competently, appropriately, and with due concern for patient welfare and quality of care.

Does presurgical IQ predict seizure outcome after temporal lobectomy? Evidence from the Bozeman Epilepsy Consortium

Summary: Purpose: Considerable debate exists Concerning whether the presence of low preoperative IQ should be a contraindication for focal resective epilepsy surgery.

Detection of changes in material-specific memory following temporal lob ectomy using the Wechsler Memory Scale-Revised ☆

To determine the utility of the Wechsler Memory Scale-Revised (WMS-R) in measuring material-specific memory changes, within-subject comparisons of the Verbal-Visual Memory Index discrepancy and discrepancy scores using short-term and delayed Logical Memory and Visual Reproduction subtests from the WMS-R were studied prior to and following temporal lobectomy among 30 patients with left temporal lobectomy, 30 with right temporal lobectomy, and 50 epileptic, non-surgical controls. The groups were matched on age, sex, handedness, age at seizure onset, duration of epilepsy, and presurgical Verbal and Performance IQ; the right temporal group had a higher mean educational level (p <.05). All surgical patients were left hemisphere dominant for speech; those who had persistent postoperative seizures were excluded from study. On retesting, left temporal lobectomy was associated with a marked change in short-term and delayed memory discrepancy scores primarily due to a drop in verbal memory. Right temporal lobectomy was not associated with a drop in visual memory, suggesting that the WMS-R appears to reflect decrements in material-specific memory following left but not right temporal lobectomy. The nonsurgical controls showed increases in both short-term and delayed memory discrepancy scores due to increases in short-term and delayed verbal memory. Relative to these controls, the absence of comparable increases in verbal memory among the right temporal patients suggests that right temporal lobectomy may be associated with risk to verbal memory.