Alteration profile of executive functions in multiple sclerosis.

OBJECTIVE: Executive functions (EF) in multiple sclerosis (MS) have been only partially studied, mainly trough the evaluation of subfunctions. The main objective was to analyse the EF alteration profile in a patients with MS sample. PARTICIPANTS AND METHODS: Case-control study, 100 patients with MS and 30 controls were evaluated by the following tests: Comprehensive Trail Making Test, Stroop Test, Wisconsin Card Sorting Test, picture completion, letter-number sequencing, comprehension and similarities of the WAIS-III scale, phonological and semantic fluency, zoo map test, temporal judgment and behavioural Dysexecutive Questionnaire (DEX-Q) of the Behavioural Assessment of the Dysexecutive Syndrome. Scores below normative values were considered pathological. Factorial analysis was used to simplify the deficits, and multiple regression and ANOVA statistics were used to analyse the relationship between clinical and cognitive variables. RESULTS: Seventy-four patients had a recurrent-relapsing course, the mean degree of disability by Expanded disability Status Scale (EDSS) was 2.7 and the mean time of evolution was 9.94 years. Eighty-five per cent presented alterations in 3 or more EF tests and 71% in 5 or more. In the factorial analysis, three groups of functions were involved: (i) cognitive flexibility (ii) inhibition and (iii) abstraction ability. Patients with a progressive course and a high EDSS had a significantly worse performance (P < 0.05). The patients showed a low awareness of their deficit in the DEX-Q. CONCLUSIONS: Cognitive flexibility, inhibition and abstraction ability were the three components of EF most deficient. The patients with the worst performance were those with progressive forms and a high EDSS.

Predicting conversion to multiple sclerosis by assessing cognitive impairment in radiologically isolated syndrome.

Up to a third of patients with radiologically isolated syndrome (RIS) exhibit lower-than-expected cognitive performances in neuropsychological evaluations, but the relationship between cognitive impairment (CI) and quantitative magnetic resonance (MRI) measures has not been stablished. Furthermore, the prognostic role of CI in RIS for conversion to MS is currently unknown. We assessed 17 patients with RIS and 17 matched healthy controls (HC) with a neurophychological battery and a 3T MRI. Six patients (35,3%) fulfilled our criterion for CI (scores 2 SDs below the mean of HC in at least two cognitive tests) (ci-RIS). The ci-RIS subgroup showed lower values of normalized brain and gray matter volumes when compared to HC. After a median follow-up time of 4.5 years, the ci-RIS subgroup presented a higher conversion rate to MS, suggesting that CI might be an independent risk factor for conversion to MS.

Executive function and memory in patients with relapsing-remitting multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system very heterogeneous in its characteristics. In contrast to the well known sensitive/motor deficits, the cognitive dysfunction has only been analyzed in the last few decades. Attention, executive function, and memory were assessed in 28 patients with recurrent-remittent MS (RRMS) (duration, median 7 years; EDSS median 2) by means of a specific neuropsychological battery. Depression (BDI), anxiety (STAI) and fatigue (FSS) were also assessed. Twenty-five of these patients were selected for statistical study because they presented deficits in some cognitive areas. Twenty-four percent of the patients displayed memory deficits and 80% showed attention and executive function deficits related to prefrontal lobe function. No global memory difficulties were found, except for immediate visual memory of complex elements (immediate recall of the Rey figure), although the visual reproduction I subtest of the WMS-R was unaffected. In RRMS patients with a relatively short duration and low level of incapacity, cognitive impairments mainly affected prefrontal functions. The difficulties in immediate visual memory of complex elements could also be explained by a failure in these areas, due to the alteration of the organization and strategic use of the material to be encoded.

Relationship between episodic memory and volume of the brain regions of two functional cortical memory systems in multiple sclerosis.

BACKGROUND/OBJECTIVE: Two functional networks are proposed as neuronal support for the complex processes of memory: the anterior temporal and the medial posterior systems. We examined the atrophy of hippocampus (HC) and of those areas constituting the two functional memory systems in multiple sclerosis (MS) patients with low disability. METHODS: Episodic memory (EM) was assessed in 88 relapsing MS patients and in 40 healthy controls using Wechsler Memory Scale III (Spanish adaptation). FreeSurfer software was used to calculate normalized volume of total cortex, grey matter, white matter, subcortical grey matter (thalamus and striatum), HC and both the anterior temporal (entorhinal, ventral temporopolar, lateral orbitofrontal, amygdala) and posterior medial systems (thalamus, parahippocampal, posterior cingulate, precuneus, lateral parietal and medial prefrontal). Linear regression analysis was used to identify predictors of memory performance. RESULTS: Total grey matter and cortex volumes correlated with all subtypes of EM, and the precuneus volume correlated with overall, immediate and delayed memories. Univariant regression analysis identified an association between the volumes of the posterior medial memory network regions and EM scores. The volume of the left precuneus area was the unique and independent predictor for all EM subtypes except for visual memory, for which left HC volume was also an independent predictor. CONCLUSION: Left precuneus volume was the best predictor of memory in relapsing MS patients with low disability and mild deficits in EM.

Neuropsychological syndromes in multiple sclerosis.

BACKGROUND: Cognitive impairment in multiple sclerosis (MS) is common (45-65%).Deficits occur in speed of information processing (SIP), memory, attention, executive functions (EF) and visuoconstruction.Involvement of cognitive functions like language and gnosis is rare and lesser known. Our aim is to describe the cognitive function and the clinical and radiological features of five patients with MS and with neuropsychological syndromes (NPS). METHOD: Retrospective review of MS patients with NPS studied, using specific tests of SIP, memory, attention, EF, visuo-spatial abilities, praxis and language. RESULTS: The sample included four women (3 relapsing-remitting MS/1 secondary progressive MS) and one man with primary progressive MS (aged between 30-55 years). Cognitive symptoms were the initial complaint in three cases. Three cases presented apperceptive agnosia and constructive apraxia, one case presented alexia with agraphia and the fifth patient presented motor aphasia. Four patients suffered cognitive dysfunction considered typical of MS. Magnetic resonance imaging (MR) in all cases showed high lesion volumes in T1 and T2-weighted sequences. A good correlation was observed between cognitive deficits and the location of the lesions in four patients. CONCLUSIONS: NPS may be the initial complaint in MS patients, often associated with other cognitive deficits, and it shows a close relationship with lesion location.