Faculty Bibliography

OBJECTIVE: This technical report and feasibility study propose a standardized method for collecting neuropsychological data in patients undergoing the deep brain stimulation (DBS) procedure. BACKGROUND: Programs for standardizing motor data collected in studies investigating surgical therapies for Parkinson disease are already widely used (e.g., Core Assessment Program for Intracerebral Transplantations). The development and rationale for the proposed Program for Neuropsychological Investigation of Deep Brain Stimulation (PNIDBS) are outlined, and support for the feasibility of these methodologies is provided via preliminary data. METHOD: The PNIDBS includes a core battery of neuropsychological tests that assesses a wide range of cognitive functions (attention, language, visuospatial, memory, and executive) as well as depression. Using the PNIDBS, three Parkinson disease and two dystonia patients were evaluated at baseline and after surgery, once with stimulation off and once with stimulation on. RESULTS: Patients with severe motor disabilities were able to complete the PNIDBS. These preliminary data suggest that the DBS procedure as a whole had a minimal impact on cognitive functioning in most patients studied. There was also some evidence that the one patient who showed cognitive decline after the DBS procedure had demographic and clinical characteristics that may have put him at risk for this decline. CONCLUSIONS: The procedures in the PNIDBS were systematically developed and are feasible to execute. The relatively brief core battery has multiple versions and can be supplemented to meet individual investigator needs. By evaluating the components of the DBS procedure (electrode placement and stimulation), the PNIDBS can address clinical questions regarding the cognitive effects of the DBS procedure as well as investigate basic scientific issues regarding how different cognitive functions are affected when subcortical-prefrontal circuits are manipulated by the DBS procedure.

OBJECT: The authors sought to determine the impact of early temporal lobectomy (in patients younger than age 17 years) on intellectual functioning. The efficacy of temporal lobectomy for treating seizures is well established and the procedure is becoming more acceptable as a treatment for children whose seizures are intractable. However, cognitive outcomes of temporal lobectomy in children and adolescents are largely unreported. The present study takes advantage of a unique multicenter collaboration to examine retrospectively intellectual functioning in a large sample of children who underwent temporal lobectomy. METHODS: Intellectual functioning was assessed before and after temporal lobectomy for treatment of medication-resistant seizures in 82 patients at eight centers of epilepsy surgery. All children underwent standard presurgical examinations, including electroencephalography-video monitoring, magnetic resonance (MR) imaging, and neuropsychological testing, at their respective centers. Forty-three children underwent left temporal lobectomy and 39 underwent right temporal lobectomy. For the entire sample, there were no significant declines in intelligence quotient (IQ) following surgery. Children who underwent left temporal lobectomy demonstrated no significant loss in verbal intellectual functioning and improved significantly in nonverbal intellectual functioning. Children who underwent right temporal lobectomy did not demonstrate significant changes in intellectual functioning. Although group scores showed no change in overall IQ values, an analysis of individual changes revealed that approximately 10% of the sample experienced a significant decline and 9% experienced significant improvement in verbal functioning. Significant improvement in nonverbal cognitive function was observed in 16% of the sample and only 2% of the sample showed significant declines. Risk factors for significant decline included older patient age at the time of surgery and the presence of a structural lesion other than mesial temporal sclerosis on MR imaging. CONCLUSIONS: The present study provides preliminary data for establishing the risk of cognitive morbidity posed by temporal lobectomy performed during childhood. With respect to global intellectual functioning, a slight improvement was significantly more likely to occur than a decline. However, there were several patients in whom significant declines did occur. It will be necessary to study further the factors associated with such declines. In addition, further study of more specific cognitive functions, particularly memory, is needed.

To determine whether dopamine metabolism is abnormal in HIV infected patients and whether dopamine metabolism abnormalities are related to specific neuropsychologic characteristics in HIV-infected patients, we measured cerebrospinal fluid (CSF) levels of homovanilic acid (HVA), the primary dopamine metabolite, in 10 HIV-infected patients and compared it to HVA levels in CSF in a group of 13 healthy control subjects. HIV-infected patients were also assessed with a battery of neuropsychologic tests and HVA levels were then correlated with performance on specific neuropsychologic tests. The mean (+/-SD) HVA level in CSF was 100.9 +/- 29.3 nmol/L in the HIV-infected study group and 230.5 +/- 50.0 nmol/L in the non-HIV-infected control group (p < 0.0001). The decrease in concentrations of HVA in CSF correlated with impairment on performance on neuropsychologic testing (Spearman r = 0.67; p = 0.03). When the relationship between HVA levels and specific cognitive domains was evaluated, we observed trends for positive correlation between HVA levels and tests that measure motor speed (r = 0.59; p = 0.074) and those testing attention, concentration, and executive control (r = 0.54; p = 0.108). There was no relationship between performance on memory tests and CSF HVA levels (r = -0.0061; p = 0.987). These results further support the hypothesis that dopaminergic dysfunction plays an important role in the pathogenesis of AIDS dementia complex (ADC) and suggest that specific motor and cognitive abnormalities may be related to depressed dopaminergic activity. This may have important implications for the development of treatments or preventive strategies for ADC

This study was designed to address the issue of whether there is a general processor for the perception of emotion or whether there are separate processors. We examined the relationships among three channels of emotional communication in 100 healthy right-handed adult males and females. The channels were facial, prosodic/intonational, and lexical/verbal; both identification and discrimination tasks of emotional perception were utilised. Statistical analyses controlled for nonemotional perceptual factors and subject characteristics (i.e. demographic and general cognitive). For identification, multiple significant correlations were found among the channels. For discrimination, fewer correlations were significant. Overall, these results provide support for the notion of a general processor for emotional perceptual identification in normal adult subjects

Although subjective complaints of word finding and naming deficits are commonly reported by patients with Lyme Borreliosis (LB), the existence of these disturbances has not been thoroughly investigated. Forty-four patients with LB and 43 healthy controls were administered a symptom questionnaire, the Boston Naming Test (BNT), the Controlled Oral Word Association Test (COWAT), and a series of category naming tasks. LB patients had a higher rate of complaints of word-finding disturbance (55% vs. 14%). Lower mean scores were observed on the BNT, but not on the COWAT, nor on category naming tasks. Thirty-six percent of the LB sample exhibited BNT scores in the impaired range. BNT scores in this group were correlated with a measure of memory retrieval, but not with verbal fluency indexes. There was no relation between naming scores and depression. LB patients exhibit impairments in word finding that appear to be secondary to a generalized retrieval deficit.

This study examined the relation between complaints of memory disturbance and measures of mood and memory functioning in 55 patients with serological evidence of late-stage Lyme Borreliosis (LB). Patients completed the Self-Ratings of Memory Questionnaire (SRMQ) and the Beck Depression Inventory. Memory functioning was assessed with the California Verbal Learning Test. Depressed patients exhibited more frequent complaints of memory disturbance on the SRMQ, although their pattern of responses did not differ from nondepressed patients. There was a significant correlation between subjective memory ratings and self-reported depression (Spearman rho = -.57, p < .001). No relation was observed between subjective memory ratings and objective memory performance. The results indicate subjective complaints of more severe memory disturbance in patients with LB and depression. Particular attention should be paid to the assessment of depression and subjective symptoms of memory disturbance when administering neuropsychological tests of memory functioning in patients with LB.

OBJECTIVE: To examine the effects of anomalous language representation (i.e., mixed- and right-cerebral dominant) on neuropsychological performance. BACKGROUND: Right cerebral language dominance resulting from early cerebral injury is associated with relatively preserved language function with decreased visuospatial ability. However, previous reports of this phenomenon have examined patients with relatively large cerebral injuries (e.g., infantile hemiplegia) or limited sample sizes. METHODS: A total of 561 patients with complex partial seizures of left temporal lobe origin were studied. Patients were classified into left (n = 455), bilateral (n = 58), and right (n = 48) language dominant groups based on Wada testing. RESULTS: Right language dominant patients performed more poorly on multiple tests of visuospatial function, including Performance IQ (PIQ), than did left language patients. No significant group differences were detected for measures of language or general verbal function. The effects of bilateral language on PIQ differed according to handedness. Lowered PIQ was present in the bilateral nondextral group but not for bilateral dextral patients, and this pattern was observed with other visuospatial measures. CONCLUSIONS: In patients with relatively small lesions restricted to the left mesial temporal lobe, a shift in language dominance to the right hemisphere is associated with decreased visuospatial functions but preserved verbal abilities. Nondextral patients with bilateral language representation also displayed decreased visuospatial performance, although dextral patients with bilateral language did not.

BACKGROUND: The emergence of psychogenic seizures after surgery for epilepsy is not well recognized. OBJECTIVES: To identify the frequency of psychogenic seizures in an 11-year surgical experience and to characterize the patients with this complication. METHODS: Ninety-six patients underwent surgery for epilepsy between 1985 and 1996. The surgical database was reviewed and all patients who experienced postoperative psychogenic seizures were identified. Patients were characterized by sex, age, psychopathologic conditions, full-scale IQ, duration of epilepsy, surgical procedure, and operative complications. Patients were compared with the surgical group as a whole for these variables. SETTING: A comprehensive epilepsy center. RESULTS: Five patients were identified: 3 men and 2 women. Mean full-scale IQ was 73 (range, 66-82). Mean age was 29.8 years (range, 22-36 years). Three patients were diagnosed as having psychosis, 1 with borderline personality disorder and 1 with generalized anxiety. Operations included 4 anterior temporal lobectomies and 1 occipital lobectomy. Two patients experienced operative complications. Compared with the surgical cohort, patients had a higher frequency of preoperative psychopathologic conditions, lower mean full-scale IQ, and a greater occurrence of operative complications. CONCLUSIONS: (1) Patients can develop new-onset psychogenic seizures after surgery for epilepsy. (2) Low full-scale IQ, serious preoperative psychopathologic conditions, and major surgical complications may be risk factors. (3) Atypical postoperative seizures should be evaluated with video electroencephalographic monitoring before concluding that they are epileptic.

PURPOSE: Considerable debate exists concerning whether the presence of low preoperative IQ should be a contraindication for focal resective epilepsy surgery. METHODS: We examined the relationship between baseline IQ scores and seizure outcome in 1,034 temporal lobectomy cases from eight epilepsy surgery centers participating in the Bozeman Epilepsy Consortium. RESULTS: Those patients who continued to have seizures following surgery had statistically lower preoperative IQ scores than those who were seizure-free (p < 0.009), but only by 2.3 points. This small but statistically significant relationship was fairly robust; it was observed across seven of the eight centers, and indicates that the findings can be generalized. Among patients with IQ scores of < or = 75, 32.8% continued to have seizures following surgery, whereas 23.8% and 16.9% were not seizure-free when IQ scores were between 76 and 109 and > or = 110, respectively. Relative risk analyses revealed no significant increase in risk among patients with low IQ scores who had no structural lesions other than mesial temporal sclerosis. However, patients with IQ scores of < or = 75 had nearly a fourfold (390%) increase in risk for continued seizures as compared with those with higher IQ scores if structural lesions were present. CONCLUSIONS: While our results suggest that preoperative IQ scores alone are not good predictors of seizure outcome and should not be used to exclude patients as potential surgical candidates. IQ scores can be useful for counseling patients and their families concerning the relative risks of surgery.