Differential Impact of Education on Cognitive Performance in Neurological Patients with Progressive Cognitive Decline.

BACKGROUND: Education has a protective effect toward cognitive decline in advanced age and is an important factor contributing to cognitive reserve. OBJECTIVE: To elucidate the interaction effect of education and global mental status on cognitive performance of older patients with progressive cognitive decline. METHODS: This retrospective study included 1,392 patients. We performed moderation regressions to examine the interaction between education and global mental status (Mini-Mental State Examination (MMSE) score) on performance in episodic memory, executive functions (EF), language, and constructional praxis tests. Significant interaction effects were further explored through separate linear regressions by MMSE level (inferior: ≤24; intermediate: 25-27; superior: 28-30). RESULTS: There was an interaction between MMSE and education for some but not all variables. At intermediate and superior MMSE levels, high-educated people had a clear advantage relative to low-educated people in verbal memory and EF tests. This advantage was not significant at an inferior MMSE level. In object naming, constructional praxis recall, and constructional praxis, high-educated people performed better than low-educated people, independently of MMSE level. CONCLUSION: Education has a differential effect on cognitive performance in patients with cognitive decline. While high education is not helpful for episodic memory and EF at low cognitive levels, it is still beneficial for retrieving words or other semantic knowledge. These findings suggest an interaction between global mental status and education on different cognitive domains and have strong clinical implications. Diagnostic judgments should be based on the knowledge of such interaction. This study highlights the beneficial but selective effects of high education.

Sector Irradiation vs. Whole Brain Irradiation After Resection of Singular Brain Metastasis-A Prospective Randomized Monocentric Trial.

To minimize recurrence following resection of a cerebral metastasis, whole-brain irradiation therapy (WBRT) has been established as the adjuvant standard of care. With prolonged overall survival in cancer patients, deleterious effects of WBRT gain relevance. Sector irradiation (SR) aims to spare uninvolved brain tissue by applying the irradiation to the resection cavity and the tumor bed. 40 were randomized to receive either WBRT (n = 18) or SR (n = 22) following resection of a singular brain metastasis. Local tumor control was satisfactory in both groups. Recurrence was observed earlier in the SR (median 3 months, 1-6) than in the WBRT cohort (median 8 months, 7-9) (HR, 0.63; 95% CI, 0.03-10.62). Seventeen patients experienced a distant intracranial recurrence. Most relapses (n = 15) occurred in the SR cohort, whereas only two patients in the WBRT group had new distant tumor manifestation (HR, 6.59; 95% CI, 1.71-11.49; p = 0.002). Median overall survival (OS) was 15.5 months (range: 1-61) with longer OS in the SR group (16 months, 1-61) than in the WBRT group (13 months, 3-52), without statistical significance (HR, 0.55; 95% CI, 0.69-3.64). Concerning neurocognition, patients in the SR group improved in the follow-up assessments, while this was not observed in the WBRT group. There were positive signals in terms of QOL within the SR group, but no significant differences in the global QLQ and QLQ-C30 summary scores were found. Our results indicate comparable efficacy of SR in terms of local control, with better maintenance of neurocognitive function. Unsurprisingly, more distant intracranial relapses occurred. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT01667640.

Cognition in multiple system atrophy: a single-center cohort study.

OBJECTIVE: Cognitive impairment in multiple system atrophy (MSA) is common, but remain poorly characterized. We evaluated cognitive and behavioral features in MSA patients and assessed between-group differences for MSA subtypes and the effect of orthostatic hypotension (OH) on cognition. METHODS: This retrospective study included 54 patients with clinical diagnosis of possible and probable MSA referred to the Department of Neurology at Medical University of Innsbruck between 2000 and 2018. Neurological work-up included comprehensive neuropsychological testing including Consortium to Establish a Registry for Alzheimer's Disease (CERAD-plus) test battery, Frontal Assessment Battery (FAB), digit span test (DST), clock drawing task (CLOX1), and Hospital Anxiety and Depression Scale (HADS-D). RESULTS: The mean MMSE score was 27.6 points. Overall, slight to moderate cognitive impairment was noted in up to 40% of patients, with predominant impairment of executive function and verbal memory. Patients with the cerebellar variant performed significantly worse than patients with the parkinsonian type (P < 0.05) in a screening of executive functions (FAB) and in phonemic verbal fluency. Depression and anxiety scores were elevated in 28% and 22% of MSA patients, respectively. Cognitive profile, depression, and anxiety levels were comparable between patients with and without OH. INTERPRETATION: Cognitive deficits are relatively frequent in MSA and primarily affect executive functions and verbal memory. Future comparative studies including Parkinson dementia, Lewy body disease, and MSA cases with and without OH are required to elucidate disease-specific cognitive profiles in these synucleinopathies and to examine the influence of cardiovascular autonomic dysfunction on cognitive function in MSA.

Cognitive outcome of pallidal deep brain stimulation for primary cervical dystonia: One year follow up results of a prospective multicenter trial.

BACKGROUND: Pallidal deep brain stimulation (DBS) is effective in alleviating motor symptoms of medication refractory cervical dystonia, but little is known about effects on cognitive functions. METHODS: As part of the first randomized, sham-controlled multicenter trial on DBS in medication-refractory primary cervical dystonia (ClinicalTrials.gov, number NCT00148889), a subgroup of 13 patients aged 39 to 69 underwent prospective neuropsychological long-term follow-up assessments. Various cognitive domains (memory, executive functions, attention, visual perception, mental arithmetic and verbal intelligence) were examined before and after 12 months of continuous DBS. RESULTS: Only the number of produced words in a verbal fluency task which included alternating categories decreased after stimulation (p = 0.020). All other cognitive domains remained unchanged. CONCLUSIONS: These findings indicate that long-term pallidal DBS for the treatment of primary cervical dystonia seems to be safe regarding global cognitive functioning.

Episodic ataxia type 2: phenotype characteristics of a novel CACNA1A mutation and review of the literature.

Episodic ataxia type 2 (EA2) is an autosomal dominant inherited neurological disorder that is characterized by paroxysmal episodes of ataxia. The causative gene for EA2 is CACNA1A which codes for the alpha 1A subunit of the voltage-gated P/Q-type calcium channel (Cav2.1). We detected a novel point mutation in the CACNA1A gene in a large Austrian family. All ten affected family members harbored a heterozygous c.3089+2T>C nucleotide exchange in intron 19. In silico modeling demonstrated a loss of the splice site of exon 19 by the mutation, which most likely results in exon skipping without frameshifting or use of an alternative splice site.Clinically, the family exhibited frequent ataxic episodes accompanied by headache in some individuals, which showed a good treatment response to acetazolamide or aminopyridine. Interictal phenotype variability was high ranging from an unremarkable clinical examination to a progressive cerebellar syndrome. Detailed cognitive testing with standardized neuropsychological tests revealed specific deficits in various domains including memory,executive functions and visual abilities. Moreover, a striking coincidence of socio-phobic behavior and anxiety disorders was detected within this family, which interfered with activities of daily living and has to be taken in consideration in EA2 patient management. We here characterize the phenotype of this novel CACNA1A mutation,review the respective literature and discuss implications on diagnosis and patient management.

Do patients with mild cognitive impairment understand numerical health information?

Patients with mild cognitive impairment (MCI) are by definition still autonomous in daily life and therefore make their own decisions, for example, concerning their own or their partners' health care. Health care information typically contains complex mathematical constructs like proportions, probabilities, and survival rates. The purpose of this study was to investigate whether patients with MCI have difficulties with understanding health numeracy questions and to explore the impact of declining cognitive functions. The performance of 25 patients with MCI in a health numeracy questionnaire was compared with the performance of a control sample including 164 healthy older adults, matched in age and educational level. Participants were asked to convert percentages, assess different probabilities, or understand the dosage of a short patient information leaflet. Additionally, neuropsychological background tests were administered. Patients with MCI answered fewer items correctly than controls in the health numeracy questionnaire. A correlation analysis showed statistically significant associations between performance in the health numeracy task and mental arithmetic, executive functions (psychomotor speed, conceptualization), and global cognitive status, respectively. Patients with MCI show problems in understanding numerical information concerning health care. Since patients with MCI are confronted with several health care decisions, special attention has to be paid to presenting information in an easily understandable way, to make additional sources of information available, and to provide adequate support.

Neuropsychological deficits associated with route learning in Alzheimer disease, MCI, and normal aging.

BACKGROUND: The background of route learning (RL) abilities in Alzheimer disease (AD), mild cognitive impairment (MCI), and normal aging needs further study. We searched for neuropsychological and demographical predictors of RL impairment. METHODS: RL was investigated in a clinical study including subjects classified as early AD (n=37), MCI (n=34), and aged normal controls (n=46). An ecological assessment procedure of RL was employed and landmarks learning and navigational abilities were evaluated. The consortium to establish a registry of Alzheimer's disease test battery was used for neuropsychological assessment. RESULTS: Almost all AD patients, and most subjects with MCI misidentified landmarks and made navigational errors when following the route without assistance. Moreover, a small subgroup of normal controls also had problems with RL. Poor RL performance was best predicted by impairments in memory and executive functions. CONCLUSIONS: RL impairment is common in early AD and MCI, and is occasionally also found in normal elderly subjects. Its characteristic appearance is a combination of poor landmark recognition and defective directional guidance. Poor RL can be predicted by neuropsychological testing. In MCI and in a subset of normal aged persons, RL impairment may herald incipient dementia.

Friedreich ataxia: executive control is related to disease onset and GAA repeat length.

Friedreich ataxia (FRDA) is the most frequent inherited ataxia. Neuropsychological studies suggest that FRDA may be associated with specific cognitive impairment. Very little is known about the relation between cognitive performance, demographics and disease-related parameters, such as GAA repeat size, age of onset and disease duration. The present investigation aimed at assessing cognitive functions in a representative sample of FRDA patients and at identifying the most relevant disease-related parameters. Twenty-nine adult FRDA patients underwent neuropsychological tests assessing executive functions, attention, memory and visual perception. Performance was compared with 28 age- and education-matched controls as well as with standardized norms. The relation between neuropsychological outcome, demographical variables and disease-related parameters was assessed. Cognitive impairment affected only a subgroup of patients and mostly concerned attentional and executive functions. Good cognitive performance was associated with a later disease onset, shorter GAA repeat length and lower burden of disease. Age at disease onset has been found to be a good predictor when a cut-off of 14 years was chosen. No correlation was found between cognitive performance and education, age or disease duration. The present study extends earlier findings in FRDA showing that performance in attentional and executive function tasks is best predicted by the age at disease onset. Moreover, executive functions show a clear relationship to disease severity and repeat size of the shorter GAA allele. These findings therefore have important implications for patient counselling regarding education and career choices.

FAB-D: German version of the Frontal Assessment Battery.

Executive dysfunction (ED) is a frequent consequence of neurological disorders, such as stroke, trauma or dementia, but also appears in normal aging. We developed a German version of the Frontal Assessment Battery (FAB-D), a short test which has previously been developed (Dubois et al., Neurology 55:1621-1626, 2000) to detect ED during bedside screening. A sample of 401 cognitively intact subjects aged 50-95 was tested with the FAB-D and several neuropsychological tests tapping executive functions, memory and calculation abilities. Aim of the study was to receive normative data for different age and educational groups, and to learn which tests predict performance on the FAB-D. We found clear effects of age and education; furthermore, FAB-D performance was predicted by other tests of executive functioning, but also by calculation and memory abilities. The present study reports data of healthy individuals and may be useful for comparing patients' performance with a normative sample.

Long-term outcome of cognitive functions, emotional behavior, and quality of life in a family with familial hemiplegic migraine.

OBJECTIVE: To investigate long-term cognitive outcome, mood, and quality of life in a family with genetically proven familial hemiplegic migraine (FHM). BACKGROUND: FHM is a rare autosomal-dominant subtype of migraine with aura, characterized by some degree of hemiparesis during the aura. In a previous study, we showed preserved and impaired cognitive functions in patients with FHM. Until now, the progression of cognitive dysfunctions has not been known. However, the ability to predict progression is important for counseling patients about education, career, and family life. METHODS: Seven years after extensive baseline neuropsychological testing, we retested 6 members of a family with FHM, including questionnaires about mood and quality of life. RESULTS: The follow-up assessment revealed no global cognitive decline. All the patients' linguistic abilities and verbal memory remained intact; however, their figural memory, attention, and some aspects of executive function were impaired. Half the patients had a slight deterioration in their visuoconstructional functions. Half had higher scores on the trait and state anxiety measures. CONCLUSIONS: Cognitive deficits in a family with FHM persisted, but without marked progression. Worsening of visuoconstructional abilities may be related to executive dysfunction, confirming a disturbance of cerebrocerebellar circuits.

Is improvement in the quality of life after subthalamic nucleus stimulation in Parkinson's disease predictable?

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) significantly improves quality of life (QoL) in PD. However, QoL fails to improve in a relevant proportion of patients. We studied clinical baseline and progression parameters associated with improvement in QoL after DBS. Data from a German randomized, controlled study comparing DBS (60 patients) with best medical treatment (59 patients) were analyzed. Changes in patients' QoL were assessed using the Parkinson's Disease Questionnaire (PDQ-39) at baseline and at the 6-month follow-up. For the STN-DBS patients, the changes in PDQ-39 were correlated with predefined clinical preoperative and progression parameters. Scores for QoL improved after STN-DBS for 57% of the patients, and for 43% patients, they did not improve. Patients with improvement in QoL showed significantly higher cumulative daily "off" time. Changes in the PDQ-39 showed a significant positive correlation with the cumulative daily off time at baseline. Logistic regression analysis revealed that 1 additional hour off time at baseline increases the odds for improvement on PDQ-39 by a factor of 1.33 (odds ratio). In the postoperative course, changes in the PDQ-39 significantly correlated with the reduction of cumulative daily off time, an improvement on the UPDRS (UPDRS III off), and positive mood changes. Among the baseline parameters, the cumulative daily off time is the strongest predictor for improvement in disease-related QoL after DBS. Improvement in QoL after STN-DBS is also correlated with changes in motor functions and changes in depression and anxiety.

Negative impact of borderline global cognitive scores on quality of life after subthalamic nucleus stimulation in Parkinson's disease.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) significantly improves quality of life (QoL) in Parkinson's disease (PD). Dementia is considered as a contraindication for STN-DBS. However, no controlled study assessed the impact of STN-DBS on the QoL and motor outcome in PD patients with a borderline global cognitive impairment. We studied clinical baseline and progression parameters in a cohort of STN-DBS patients with a global cognitive score still in the non-demented range but scoring in the lowest quartile of the Mattis Dementia Rating Scale (MDRS), a measure of global cognitive functioning. Data from a German randomised controlled study comparing DBS (60 patients) with best medical treatment (BMT, 59 patients) were analysed. Changes in patients' QoL scores were assessed using the Parkinson's disease questionnaire (PDQ-39) at baseline and at the 6 months follow up. Patients were split into four groups according to their MDRS performance at baseline and these groups were compared in the context of motor outcome and QoL. Twelve out of sixty patients of the STN-DBS group scored in the lowest quartile of the MDRS (range between one hundred thirty and one hundred thirty seven points). An individual analysis revealed that 3 of 12 patients showed a clinical relevant improvement in QoL whereas the group statistics did not reveal any significant improvement in QoL measures after STN-DBS compared to the BMT group. Since this failure to improve in QoL cannot be explained by a failure to improve in motor functions, stimulation settings and psychiatric scales after STN-DBS, the failure to improve in QoL in patients with a borderline global cognitive score might be specifically related to lower cognitive functioning.

Risk factors for executive dysfunction after subthalamic nucleus stimulation in Parkinson's disease.

A slight decline in cognitive functions and especially in executive functioning after deep brain stimulation (DBS) of the nucleus subthalamicus (STN) in patients with Parkinson's disease (PD) has been described. This study evaluated baseline parameters that contribute to a deterioration of cognitive functioning after DBS. We analyzed data from the neuropsychological protocol in a randomized controlled study comparing DBS with best medical treatment (BMT). Change scores were calculated for the cognitive domains "global cognitive functioning," "memory," "working memory," "attention," and "executive function." These domain-specific change scores were correlated with previously defined preoperative parameters. Compared with the BMT group (63 patients), the STN-DBS group (60 patients) showed a significant decline only in the domain executive function 6 months after DBS, which was significantly correlated with age, levodopa-equivalence dosage (LED) and axial subscore of the UPDRS in the off-medication state at baseline. Multiple regression analysis showed that these three factors explained, however, only about 23% of the variance. Patients with higher age, higher baseline LED, and/or higher axial subscore of the UPDRS at baseline have an increased risk for worsening of executive function after STN-DBS. High scores of these factors might reflect an advanced stage of disease progression. As these baseline factors explained the variance of the change score executive function only to a minor proportion, other factors including the surgical procedure, the exact placement of the electrode or postsurgical management might be more relevant for a decline in executive functioning after STN-DBS.

Cognitive functions, emotional behavior, and quality of life in familial hemiplegic migraine.

OBJECTIVES: To describe the cognitive functions, mood, and quality of life in a family with genetically proved familial hemiplegic migraine (FHM), carrying a missense mutation on chromosome 19 (T666M), corresponding to the most frequent FHM subtype. BACKGROUND: FHM is an autosomal dominant subtype of migraine with an aura, characterized by hemiparesis during the aura. Whereas the genetic background of FHM has been studied intensely, less attention has been paid to cognitive functions and mood between attacks. METHOD: Six patients performed neuropsychologic assessment between attacks. Depression, anxiety, and quality of life were evaluated by questionnaires. Cerebral magnetic resonance imaging was performed. RESULTS: Neuropsychologic assessment revealed a distinct pattern of preserved and impaired functions. Whereas linguistic abilities and verbal memory were intact, all patients showed deficits in figural memory, executive functions, in some aspects of attention, and in dexterity. Intelligence of 1 patient was below average. All but 1 patient reported normal quality of life; there were no symptoms of depression or state anxiety. All patients showed cerebellar atrophy and cerebellar ataxia. CONCLUSION: Cognitive abnormalities and cerebellar atrophy were found in all patients. FHM-related cognitive deficits may be associated to a disturbance of cerebrocerebellar circuits.

Neuropsychological and psychiatric changes after deep brain stimulation for Parkinson's disease: a randomised, multicentre study.

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) reduces motor symptoms in patients with Parkinson's disease (PD) and improves their quality of life; however, the effect of DBS on cognitive functions and its psychiatric side-effects are still controversial. To assess the neuropsychiatric consequences of DBS in patients with PD we did an ancillary protocol as part of a randomised study that compared DBS with the best medical treatment. METHODS: 156 patients with advanced Parkinson's disease and motor fluctuations were randomly assigned to have DBS of the STN or the best medical treatment for PD according to the German Society of Neurology guidelines. 123 patients had neuropsychological and psychiatric examinations to assess the changes between baseline and after 6 months. The primary outcome was the comparison of the effect of DBS with the best medical treatment on overall cognitive functioning (Mattis dementia rating scale). Secondary outcomes were the effects on executive function, depression, anxiety, psychiatric status, manic symptoms, and quality of life. Analysis was per protocol. The study is registered at ClinicalTrials.gov, number NCT00196911. FINDINGS: 60 patients were randomly assigned to receive STN-DBS and 63 patients to have best medical treatment. After 6 months, impairments were seen in executive function (difference of changes [DBS-best medical treatment] in verbal fluency [semantic] -4.50 points, 95% CI -8.07 to -0.93, Cohen's d=-;0.4; verbal fluency [phonemic] -3.06 points, -5.50 to -0.62, -0.5; Stroop 2 naming colour error rate -0.37 points, -0.73 to 0.00, -0.4; Stroop 3 word reading time -5.17 s, -8.82 to -1.52, -0.5; Stroop 4 colour naming time -13.00 s, -25.12 to -0.89, -0.4), irrespective of the improvement in quality of life (difference of changes in PDQ-39 10.16 points, 5.45 to 14.87, 0.6; SF-36 physical 16.55 points, 10.89 to 22.21, 0.9; SF-36 psychological 9.74 points, 2.18 to 17.29, 0.5). Anxiety was reduced in the DBS group compared with the medication group (difference of changes in Beck anxiety inventory 10.43 points, 6.08 to 14.78, 0.8). Ten patients in the DBS group and eight patients in the best medical treatment group had severe psychiatric adverse events. INTERPRETATION: DBS of the STN does not reduce overall cognition or affectivity, although there is a selective decrease in frontal cognitive functions and an improvement in anxiety in patients after the treatment. These changes do not affect improvements in quality of life. DBS of the STN is safe with respect to neuropsychological and psychiatric effects in carefully selected patients during a 6-month follow-up period. FUNDING: German Federal Ministry of Education and Research (01GI0201).

Verbal numerosity estimation deficit in the context of spared semantic representation of numbers: a neuropsychological study of a patient with frontal lesions.

Patients with frontal lobe damage have been shown to produce implausible answers in cognitive estimation, a task requiring approximate answers to quantity-related questions of general semantic knowledge. We investigated a patient with frontal lobe damage who presented executive deficits and difficulties in cognitive estimation. The patient also showed difficulties in verbal numerosity estimation (approximately evaluating the quantity of visually presented sets of items), as he produced extreme answers well outside healthy participants' range of answers. A series of tasks evidenced intact number processing and well preserved semantic representation of numbers. Detailed investigation of estimation processes suggested a deficit at the level of translation from an intact semantic representation of numbers to output, whether verbal or non-symbolic. This case study allows disentangling different processes involved in estimation and contributes to a better understanding of the cognitive estimation deficits frequently reported for patients with frontal lesions.

Language lateralization in temporal lobe epilepsy: a comparison between fMRI and the Wada Test.

PURPOSE: Recent studies have claimed that language functional magnetic resonance imaging (fMRI) can identify language lateralization in patients with temporal lobe epilepsy (TLE) and that fMRI-based findings are highly concordant with the conventional assessment procedure of speech dominance, the intracarotid amobarbital test (IAT). METHODS: To establish the power of language fMRI to detect language lateralization during presurgical assessment, we compared the findings of a semantic decision paradigm with the results of a standard IAT in 68 patients with chronic intractable right and left temporal lobe epilepsy (rTLE, n=28; lTLE, n=40) who consecutively underwent a presurgical evaluation program. The patient group also included 14 (20.6%) subjects with atypical (bilateral or right hemisphere) speech. Four raters used a visual analysis procedure to determine the laterality of speech-related activation individually for each patient. RESULTS: Overall congruence between fMRI-based laterality and the laterality quotient of the IAT was 89.3% in rTLE and 72.5% in lTLE patients. Concordance was best in rTLE patients with left speech. In lTLE patients, language fMRI identified atypical, right hemisphere speech dominance in every case, but missed left hemisphere speech dominance in 17.2%. Frontal activations had higher concordance with the IAT than did activations in temporoparietal or combined regions of interest (ROIs). Because of methodologic problems, recognition of bilateral speech was difficult. CONCLUSIONS: These data provide evidence that language fMRI as used in the present study has limited correlation with the IAT, especially in patients with lTLE and with mixed speech dominance. Further refinements regarding the paradigms and analysis procedures will be needed to improve the contribution of language fMRI for presurgical assessment.

Counting complex dot patterns in Alzheimer's disease.

Patients affected by Alzheimer's disease (DAT) showed considerable difficulties assessing the numerosity of complex dot patterns (up to 30 dots). Patients' and controls' performance was found to be modulated by the spatial array of dot patters. Dots presented in curved lines were easier to count than dots in circle arrays or in random arrays. Highly significant between group differences were found in counting dots in circle arrays, but not in counting curved lines. Patients and controls differed in the choice of counting strategies. While controls efficiently adapted their counting strategies to the respective dot patterns, DAT patients were not able to adapt counting strategies to the requirements of the spatial arrays. Analysis of error types further evidenced the particular difficulties of patients. Several recounts in counting circle arrays reflected difficulties to stop counting, while omissions in random patterns suggested deficits in monitoring already counted items. Results of this study suggest that deficits in executive functions prevented patients from selecting and adapting counting strategies in order to keep track of already counted items, to enhance accuracy and to reduce demands on cognitive resources.

Hippocampal formation involvement in a language-activation task in patients with mesial temporal lobe epilepsy.

PURPOSE: The study aims to explore the contribution of the hippocampal formation to the retained language-comprehension network in patients with unilateral mesial temporal lobe epilepsy (TLE). METHODS: We performed a functional magnetic resonance (MRI) study based on a language comprehension paradigm in 45 right-handed patients with unilateral mesial TLE and 35 healthy control subjects. Activations in the hippocampal formations in both hemispheres were analyzed for each subject as well as for groups of left TLE, right TLE, and controls. RESULTS: In sum, 82% of TLE patients displayed hippocampal activations. A significant difference in hippocampal activation between left and right TLE was found: Right TLE patients showed increased activity in the left hippocampal formation compared with left TLE patients. In contrast, patients with left TLE did not show increased activity in the right hippocampal formation compared with right TLE patients. In comparison with a healthy control group, right TLE patients activated the left hippocampal formation to a greater extent, whereas patients with left TLE did not activate the right hippocampal formation to a greater degree. These findings point to an increased involvement of the left hippocampal formation during a language-comprehension task in right TLE patients. In contrast, left TLE in right-handed patients seems not associated with an enhanced involvement of the right hippocampal formation in retained language comprehension. CONCLUSIONS: These findings suggest that effective language comprehension in right-handed subjects with TLE depends on the involvement of the left hippocampal formation and underline the risks of postoperative language decline in patients with left TLE.

Language and arithmetic--a study using the intracarotid amobarbital procedure.

The intracarotid amobarbital procedure is used as a standard procedure in presurgical evaluation to assess hemispheric lateralization of language and memory, but has not been applied to investigate numerical processing. Patients with medically intractable epilepsy (n=20) were consecutively recruited during a presurgical evaluation programme. All 14 patients with left-lateralized language showed better arithmetic performance with the left hemisphere (intracarotid amobarbital procedure right), while five out of six patients with bilateral or right-hemispheric language representation showed better performance with the right hemisphere (intracarotid amobarbital procedure left). Furthermore, in patients with left-lateralized language, an interaction between intracarotid amobarbital procedure and type of arithmetic operation was found. The study suggests a close association between language lateralization and hemispheric specialization for arithmetic processing.