Cognitive deficits in multiple sclerosis

Multiple Sclerosis (MS) is a representative autoimmune demyelinating disease of the central nervous system (CNS) affecting mainly young adults. Clinician's interests are mainly focused on the physical impairment that MS may bring. However, during the past few decades there is an increasing awareness of cognitive dysfunction in MS patients, a symptom already described for MS cases by Charcot. It is estimated that cognitive dysfunction may be present in more than 50% of the MS patients during their lifetime and may cause a devastating impact on every day function, independently on the degree of physical disability. In several neuropsychological studies it has been reported that recent memory, attention, processing speed, visuospatial abilities and executive functions, are among the domains of cognitive function most commonly affected in MS. On the contrary, language skills and intellectual functions are generally preserved. However, patients may either underestimate their deficits due to metamemory impairment or overestimate them due to depression. In addition, one of the major problems in the every day clinical practice remains the assessment of cognitive function, since the mini – mental state examination which is included in a routine neurological evaluation, is insensitive to MS-related cognitive impairment, especially a non-severe one. It is therefore evident that a brief, cost-effective and reliable neuropsychological assessment may be of a great value and may contribute to a global evaluation of the disease progression in an individual patient. During the last decade, an enormous progress in MS treatment has been made. However, most clinical trials of disease modifying therapies have been focused on the role of the administered agents in controlling the physical disability of MS patients. Only in a few multicenter studies cognitive function was among the outcomes studied and preliminary results indicate that currently used immunomodulatory and symptomatic agents may positively influence the cognitive outcome of the patient. There is considerable hope that by altering the cerebral demyelinating process, a slower decline in cognitive functions may be accomplished. Furthermore, combination of drug therapy with cognitive rehabilitation techniques is expected to result in the improvement of the quality of life standards of the MS patients.