Brain : a journal of neurology
-
Multiple system atrophy (MSA) has varying clinical (MSA-P versus MSA-C) and pathological [striatonigral degeneration (SND) versus olivopontocerebellar atrophy (OPCA)] phenotypes. To investigate the spectrum of clinicopathological correlations, we performed a semi-quantitative pathological analysis of 100 MSA cases with well-characterized clinical phenotypes. In 24 areas, chosen from both the striatonigral (StrN) and olivopontocerebellar (OPC) regions, the severity of neuronal cell loss and gliosis as well as the frequency of glial (oligodendroglial) cytoplasmic inclusions (GCIs) and neuronal cytoplasmic inclusions (NCIs) were determined. ⋯ As might be expected, there was a significant difference in the severity of bradykinesia and the presence of cerebellar signs between the pathological phenotypes: the SND phenotype demonstrates the most severe bradykinesia and the OPCA phenotype the more frequent occurrence of cerebellar signs, confirming that the clinical phenotype is dependent on the distribution of pathology within the basal ganglia and cerebellum. Putaminal involvement correlated with a poor levodopa response in MSA. Our finding that relatively mild involvement of the substantia nigra is associated clinically with manifest parkinsonism, while more advanced cerebellar pathology is required for ataxia, may explain why the parkinsonian presentation is predominant over ataxia in MSA.
-
The purpose of this study was to assess whether the histological subtype of focal cortical dysplasia and dual pathology affect surgical outcome in patients with medically intractable epilepsy due to focal cortical dysplasia (FCD). We retrospectively analysed the outcome of 67 patients from 2 to 66 years of age at follow-up periods of 6 to 48 months after epilepsy surgery. Histological subtypes were classified according to Palmini and included a few cases with mild histological abnormalities corresponding to the definition of mild malformations of cortical development. ⋯ We conclude that patients with FCD type 1 and mMCD had a better outcome compared with those with more severe forms of cortical dysplasia. A higher incidence of FCD type 1 in temporal localization did not allow the effects of histological subtype and localization to be separated. A subanalysis of extratemporal FCDs, however, revealed a similar tendency for a better outcome with FCD type 1, suggesting that the histological subtype itself seems to be at least a relevant cofactor influencing postsurgical outcome.
-
The excitability of the cerebral cortex in the interictal state of migraine appears to be fundamental in the brain's susceptibility to migraine attacks. Subpopulations of cortical neurons are reported to have different physiological response properties to different interstimulus intervals (ISIs) and, hence, may be differentially altered or modulated in migraine. The aim of this study therefore was to evaluate response characteristics of temporally and spatially defined neuronal subpopulations in the cortex of migraineurs. ⋯ This hyperexcitability appears not to be related to habituation since habituation was not found in the control subjects. In contrast, the magnitude of P35m is not pathophysiologically linked to the interictal state of migraine. Furthermore, the cellular mechanisms causing ISI-dependent depression of N20m and P35m are not altered in migraine.
-
To determine the usefulness of [18F]fluorodeoxyglucose (FDG) whole body FDG-PET in the diagnosis of tumours in patients with paraneoplastic neurological syndromes (PNS), we prospectively studied 20 patients with paraneoplastic antibodies in whom conventional imaging gave negative or inconclusive results for the presence of tumour. All 20 patients had neurological manifestations compatible with PNS and well-characterized paraneoplastic antibodies (12 anti-Hu, one anti-Hu and anti-CV2, one anti-CV2, four anti-Yo, one anti-Ri and one anti-amphiphysin). The mean delay between the onset of neurological symptoms and FDG-PET was 10 months (range 1-54). ⋯ Over the study period, we saw 73 other patients with PNS and paraneoplastic antibodies. A tumour was demonstrated in 71 out of 73 by conventional techniques. Since false-positive and false-negative results are possible with FDG-PET and in most patients with PNS, the tumour is demonstrated by conventional techniques, we believe that FDG-PET should be reserved, at the moment, for patients with well-defined PNS antibodies when conventional imaging fails to identify a tumour or when lesions are difficult to biopsy.
-
A better understanding of the mechanisms involved in human higher cortical functions requires a detailed knowledge of neuronal connectivity between functional cortical regions. Currently no good method for tracking in vivo neuronal connectivity exists. We investigated the inter-areal connections in vivo in the human language system using a new method, which we termed 'cortico-cortical evoked potentials' (CCEPs). ⋯ Different from the classical Wernicke-Geschwind model, the present study revealed a bidirectional connection between Broca's and Wernicke's areas probably through the arcuate fasciculus and/or the cortico-subcortico-cortical pathway. CCEPs were recorded from a larger area than the posterior language area identified by electrical stimulation. This suggests the existence of a rather broad neuronal network surrounding the previously recognized core region of this area.