Characterization of social cognition impairment in multiple sclerosis.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) has been associated with deficits in social cognition. However, little is known about which domains of social cognition are predominantly affected and what other factors are associated with it. The aim was (i) to characterize social cognition deficit in a group of MS outpatients and (ii) to relate impairment in social cognition to overall cognitive status, depression and fatigue. METHODS: Thirty-five MS patients (mean disease duration 12.9 years, median Expanded Disability Status Scale (EDSS) 3 and 34 healthy controls (HCs) were examined using the German version of the Geneva Social Cognition Scale to measure different domains of social cognition. Standard neuropsychological testing was applied to all patients and to 20 HCs. Patient-reported outcomes included questionnaires for fatigue, depression, anxiety and executive-behavioural disturbances. RESULTS: The mean social cognition raw score was lower in the MS patients compared to the HCs (86.5 ± 8.7 vs. 91.2 ± 5.9, P = 0.005; d = 0.6) and did not correlate with EDSS or disease duration. The difference was driven by facial affect recognition and the understanding of complex social situations (14% and 23% of patients respectively under the cut-off). The impairment in these two tasks did not correlate with general cognitive performance or depression but with fatigue. CONCLUSIONS: The impairment in our group was restricted to high order and affective social cognition tasks and independent of general cognitive performance, EDSS, disease duration and depression. Fatigue correlated with social cognition performance, which might be due to common underlying neuronal networks.

Creutzfeldt-Jakob disease revealed by a logopenic variant of primary progressive aphasia.

Logopenic aphasia, mainly characterized by word anomia, sentence and phrase comprehension difficulties secondary to phonological loop deficits but relatively preserved single word comprehension and no agrammatism, is one of the 3 main variants of primary progressive aphasia (PPA). We describe the first case of PPA that fulfilled clinical criteria of logopenic aphasia but showed abnormal DWI hyperintensities that were predominant on the left hemisphere and compatible with Creutzfeldt-Jakob disease (CJD). After abnormally long isolated language deficits, the patient rapidly worsened and died. Autopsy performed 18 months after onset of language difficulties confirmed the diagnosis. We therefore advocate performing DWI sequences in any suspicion of PPA in order to rule out CJD.

Theory of mind tasks and executive functions: a systematic review of group studies in neurology.

A growing number of studies have been addressing the relationship between theory of mind (TOM) and executive functions (EF) in patients with acquired neurological pathology. In order to provide a global overview on the main findings, we conducted a systematic review on group studies where we aimed to (1) evaluate the patterns of impaired and preserved abilities of both TOM and EF in groups of patients with acquired neurological pathology and (2) investigate the existence of particular relations between different EF domains and TOM tasks. The search was conducted in Pubmed/Medline. A total of 24 articles met the inclusion criteria. We considered for analysis classical clinically accepted TOM tasks (first- and second-order false belief stories, the Faux Pas test, Happe's stories, the Mind in the Eyes task, and Cartoon's tasks) and EF domains (updating, shifting, inhibition, and access). The review suggests that (1) EF and TOM appear tightly associated. However, the few dissociations observed suggest they cannot be reduced to a single function; (2) no executive subprocess could be specifically associated with TOM performances; (3) the first-order false belief task and the Happe's story task seem to be less sensitive to neurological pathologies and less associated to EF. Even though the analysis of the reviewed studies demonstrates a close relationship between TOM and EF in patients with acquired neurological pathology, the nature of this relationship must be further investigated. Studies investigating ecological consequences of TOM and EF deficits, and intervention researches may bring further contributions to this question.

Pure global acalculia following a left subangular lesion.

We describe the case of a right-handed patient who presented a severe acalculia in the context of a pure Gerstmann syndrome following a subangular lesion that spared the left inferior parietal lobule (IPL). The patient showed impairments in Arabic and verbal codes, in number production and comprehension, as well as in numerical facts and problem solving. By using the EC301 calculation battery, semantic and syntactic tasks in Arabic and verbal codes, we tested the different hypotheses raised by the cognitive neuropsychological models of acalculia. The patients' difficulties, which were not associated with a general intellectual deterioration, and those affecting number processing as a particular semantic class, were indicative of a "global acalculia". This deficit, which exceeded the anarithmetia usually described in Gerstmann syndrome following left IPL lesion, suggested that the isolation of this area may constitute a sufficient condition for producing such a global acalculia. These results are discussed in terms of a disorder in the manipulation of mental images of spatially related objects.

A pure case of Gerstmann syndrome with a subangular lesion.

The four symptoms composing Gerstmann's syndrome were postulated to result from a common cognitive denominator (Grundstörung) by Gerstmann himself. He suggested that it is a disorder of the body schema restricted to the hand and fingers. The existence of a Grundstörung has since been contested. Here we suggest that a common psychoneurological factor does exist, but should be related to transformations of mental images rather than to the body schema. A patient (H.P.) was studied, who presented the four symptoms of Gerstmann's syndrome in the absence of any other neuropsychological disorders. MRI showed a focal ischaemic lesion, situated subcortically in the inferior part of the left angular gyrus and reaching the superior posterior region of T1. The cortical layers were spared and the lesion was seen to extend to the callosal fibres. On the basis of an extensive cognitive investigation, language, praxis, memory and intelligence disorders were excluded. The four remaining symptoms (finger agnosia, agraphia, right-left disorientation and dyscalculia) were investigated thoroughly with the aim of determining any characteristics that they might share. Detailed analyses of the tetrad showed that the impairment was consistently attributable to disorders of a spatial nature. Furthermore, cognitive tests necessitating mental rotation were equally shown to be impaired, confirming the essentially visuospatial origin of the disturbance. In the light of this report, the common cognitive denominator is hypothesized to be an impairment in mental manipulation of images and not in body schema.

Semantically-triggered reading epilepsy: an experimental case study.

Primary reading epilepsy (PRE) is a rare syndrome in which epileptic seizures are electively provoked by reading. Cognitive neuropsychology has demonstrated the existence of at least two pathways for reading, the sublexical pathway involved in converting graphemes to phonemes, and the lexical pathway used when meaning is conveyed. Which of these specific pathways is relevant in triggering epileptic discharges remains largely unknown. We report the case of a patient suffering from PRE in which the two routes were distinguished on the basis of the reading material employed. Significantly less epileptic discharges were observed when the patient read non-words than words. In view of our findings, we tentatively contrast a lexical form of PRE, triggered by the activation of semantic knowledge structures, with a sublexical form, triggered by non-word reading. Evidence from the literature suggests that the former is characterized by bilateral EEG activating patterns, whereas the latter involves preferentially the left hemisphere.