Faculty Bibliography

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.

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.

OBJECTIVES: To examine the degree and frequency of reductions in hippocampal volume in patients with temporal lobe epilepsy with and without a history of febrile seizures. METHODS: In vivo measures of hippocampal volume were computed from three dimensional gradient echo (FLASH) images in 44 patients undergoing comprehensive evaluations for epilepsy surgery. Twenty one patients (48%) reported a history of febrile seizures. The volumes from these patients were compared with those from 23 patients without a history of febrile seizures and 34 healthy controls. RESULTS: The febrile seizure group had significant reductions in volume, both ipsilateral (30% decrease) and contralateral (15% decrease), to the EEG seizure focus. Twelve of 18 patients with febrile seizures exhibited clinically significant ipsilateral volume reductions, defined as volumes falling 2 SD below the mean obtained from the control sample. Only four of 19 patients without febrile seizures exhibited this degree of reduction. No significant correlations were found between seizure variables (for example, duration of epilepsy, seizure frequency) and ipsilateral reductions in volume. However, a significant inverse correlation (r=-0.45, P<0.05) between seizure frequency and the volume of the hippocampus contralateral to the seizure focus was found in the febrile seizure group. CONCLUSION: These results suggest that a history of febrile seizures is associated with the finding of a smaller hippocampus on the side ipsilateral to the subsequent temporal lobe focus whereas chronic factors seem to be be related to pathology contralateral to the seizure focus.

Tests of facial recognition and spatial learning were administered to presurgical patients with unilateral temporal lobe EEG foci. Right temporal lobe patients obtained lower facial recognition scores than left temporal lobe patients. The groups performed equally on the spatial learning test. A factor analysis revealed two independent factors: a general visuospatial factor and a more specific facial identification factor. The findings provide support for the existence of two dissociable visual processing systems. Memory impairments associated with right temporal lobe dysfunction may be characterized as an impairment in a ventral visual processing system responsible for facial memory and pattern recognition.

BACKGROUND: Converging evidence has suggested that the abnormalities in brain morphology observed in schizophrenia are similar to those seen in temporal lobe epilepsy (TLE). The purpose of this study was to compare the features of these groups directly with measures of the brain using magnetic resonance (MR) morphometry. METHOD: Morphometric measures of ventricular and hippocampal volumes obtained from FLASH MR images were studied in 32 patients with first-episode schizophrenia (FES), 39 patients with TLE (21 left, 18 right), and 42 healthy controls. RESULTS: Ventricular volumes in the FES and TLE groups were both significantly larger that those seen in controls and did not differ from each other. The FES group showed significantly larger temporal horns, while the TLE group had relatively larger frontal horns. Analyses of hippocampal volumes revealed a significant group by hemisphere effect. The FES group showed relative reductions in left hippocampal volume that were comparable only to TLE patients with seizures originating from the left hemisphere. CONCLUSION: The results indicate that FES and TLE groups both show evidence of ventricular enlargement. Lateralised morphological abnormalities of the hippocampal formation in FES and left TLE are comparable, and may be specific to temporolimbic regions.