| Περίληψη: | While the prevalence and pattern of cognitive dysfunction in multiple sclerosis (MS) is well documented, cognitive deterioration remains one of the most disabling characteristics of MS, and among the most difficult symptoms to manage. The impact of cognitive dysfunction in this population is significant with negative consequences on activities of daily living, loss of employment and ultimately quality of life. Past and current pharmacological treatments have shown inconsistent findings in alleviating cognitive impairment in MS patients requiring further clarification This inconsistency regarding the effects of pharmacological interventions on cognition, coupled with the reduced ability to effectively handle everyday tasks, loss of employment and social interaction capacity, prioritizes the need for utilizing potentially more effective non-pharmacological, neurobehavioral interventions to adequately address cognitive dysfunction and everyday functioning abilities. Although the utilization of compensatory strategy training and use of external aids may be used in cognitively impaired MS patients with extensive brain atrophy, when neural plasticity mechanisms might be hampered and cortical reorganization of the brain is limited, restorative or functional cognitive training interventions utilizing either computer assisted or manualized interventions have demonstrated positive pre to post treatment effects, including good adherence, acceptability and safety rates.
In this multicenter, randomized controlled trial we implemented a computer assisted (RehaCom software), functional training cognitive rehabilitation intervention of 10-weeks duration (twice weekly for 60 minutes), on (n =32) (Intervention group; IG), cognitively impaired relapsing remitting multiple sclerosis (RRMS) patients, with low disability status (EDSS = 3.14), and compared them to a demographically and clinically matched group of cognitively impaired RRMS patients (n =26) (Control group; CG), who received only standard clinical care. Our data showed, that this relatively short period of domain specific functional cognitive training (attention, processing speed, executive functions and episodic memory), was helpful in ameliorating the trained functions, and that effectiveness persisted at 6-months follow up for the attention domain. For the other trained domains, performance did not deteriorate to pretreatment levels after 6-months, implying a possible protective long-term effect of the intervention in terms of cognitive deterioration rate. Our findings are further supported by recent explorative functional neuroimaging studies, which have reported that cognitive rehabilitation interventions, including those that incorporated the RehaCom software, may induce an increase in the brain activation of treated patients and more efficient neural network activity.
Another positive attribute of the rehabilitation intervention, was that the majority of treated MS patients responded positively at post treatment assessment to four verbal questions, related to the benefit gained from the intervention and their everyday functioning capacity.
Moreover, a cohort of cognitively impaired RRMS patients (n=31), that underwent regional cerebral blood flow (rCBF) brain SPECT evaluation at baseline, demonstrated greater hypoperfusion rates in several predefined Brodmann areas and lobes of the brain, relative to demographically matched healthy controls according to an established normative database (NeuroGam). Furthermore, a different pattern of cortical hypoperfusion severity, between patients with more severe (n=19); (failed ≥ 2 cognitive tests on the administered neuropsychological battery at baseline with performance ≤ 1.5 SD below normative data mean) and less severe (n=12); (failed 1 cognitive test on the administered neuropsychological battery with performance ≤ 1.5 SD below normative data mean) cognitive deterioration was established. Another significant contribution of the study was the important associations that were established between results of perfusion decrements and neuropsychological performance. We found moderate associations between a measure of verbal fluency-language expression and reduced blood flow in the left posterior lateral prefrontal cortex, verbal episodic memory and hypoperfusion in the left temporal lobe, and strong relationships between two measures of executive functions, and severity of hypoperfusion in the left frontal lobes respectively.
Overall, the study demonstrates the potential utility of brain perfusion SPECT in monitoring cognitively deteriorated RRMS patients, and due to its accessibility, relatively low cost, practical ease and provision of objective quantitative information, it may be utilized in order to complement neuropsychological assessment in surveillance of cognitive decline in RRMS patients.
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