Asymptomatic subjects differ less from their twin siblings with MS than from healthy controls in cognitive functioning. A Finnish Twin Cohort study.

BACKGROUND: Cognitive impairment develops in some MS patients at any time during the course of the disease regardless of whether the patients have neurological disability or not. Underlying causes for the MS related cognitive decline are yet poorly understood but both genetic and environmental risk factors have been proposed. OBJECTIVES: To assess whether the cognitive performance differs between subjects with multiple sclerosis (MS) and their asymptomatic co-twins. METHODS: Nineteen twin pairs discordant for MS recruited from the Finnish Twin Cohort were studied neurologically and with a comprehensive neuropsychological test battery. Control group included twenty age and education matched healthy subjects. RESULTS: Compared with the control subjects, the asymptomatic co-twins of MS patients performed significantly less well in tests of naming, verbal reasoning, visuospatial performance, processing speed, attention, verbal memory and learning. The twins with MS performed significantly less well than their co-twins in the SDMT evaluating processing speed, in visual learning and in word fluency. CONCLUSIONS: The lack of significant difference in majority of neuropsychological tests between the MS patients and their co-twins as well as considerable differences between asymptomatic co-twins and healthy controls may suggest that the cognitive performance may be partly developmental and regulated both by genes and shared environmental factors.

Cognitive dysfunction in primary progressive multiple sclerosis: a neuropsychological and MRI study.

Although cognitive dysfunction is known to occur in multiple sclerosis (MS), only few studies have reported cognitive performance in patients with primary progressive MS (PPMS). To find out the pattern of cognitive performance in PPMS, 28 PPMS patients underwent an extensive battery of neuropsychological tests. The results were compared to those of healthy controls (n = 20) and patients with secondary progressive MS (SPMS, n = 28). Furthermore, the results of neuropsychological tests in PPMS were correlated to magnetic resonance imaging findings. Our study showed that the PPMS patients have deficits in several cognitive domains when compared to age-matched and education-matched controls, but the cognitive impairment in the PPMS and SPMS patients appeared to be similar. Cognitive deficits in PPMS patients correlated with diffuse brain lesion, T1- and T2-lesion load, but no correlations were found with atrophy.

Computerised volumetric analysis of lesions in multiple sclerosis using new semi-automatic segmentation software.

The paper describes the application of new semi-automatic segmentation software to the task of detection of anatomical structures and lesion and their three-dimensional (3D) visualisation in 23 patients with secondary progressive multiple sclerosis (MS). The purpose is to study the correlation between magnetic resonance imaging (MRI) parameters (volumes of plaques and cerebrospinal fluid spaces) and clinical deficits (neurological deficits in the form of EDSS and RFSS scores, and neuropsychological deficits). The software operates in PC/Windows and PC/NeXTstep environments and utilises graphical user interfaces. Quantitative accuracy is measured by performing segmentation of fluid-filled syringes (relative error of 1.5%), and reproducibility is measured by intra- and inter-observer studies (3% and 7% variability, respectively). The mean volumes of MS plaques show significant correlations with the total RFSS scores (p = 0.04). Relative intracranial cerebrospinal fluid (CSF) space volumes show statistically significant correlation with EDSS scores (p = 0.01). The mean volume of MS plaques shows a significant correlation with the overall neuropsychological deficits (p = 0.03). 3D visualisation helps to understand the relationship of lesions to the surrounding brain structures. The use of semiautomatic segmentation techniques is recommended in the clinical diagnosis of MS patients.