University of Jyväskylä

Dissertation: 17.11.2017 Three Different Approaches to Cognitive Fatigue in Patients with a Mild Form of Multiple Sclerosis: Objective Cognitive, Subjective Cognitive and Neurophysiological (Liuha)

Start date: Nov 17, 2017 12:00 PM

End date: Nov 17, 2017 03:00 PM

Location: Seminaarinmäki, Old festival hall (S212)

SannaLiuhanetti.jpg
Sanna Liuha
PsL Sanna Liuha defends her doctoral dissertation in Psychology ”Three Different Approaches to Cognitive Fatigue in Patients with a Mild Form of Multiple Sclerosis: Objective Cognitive, Subjective Cognitive and Neurophysiological”. Opponent  PsT, Adjunct Professor Eija Rosti-Otajärvi (Tampere University Hospital) and custos Adjunct Professor Jukka Kaartinen (University of Jyväskylä). The doctoral dissertation is held in Finnish.

Abstract

Three different approaches to cognitive fatigue in patients with a mild form of multiple sclerosis: Objective cognitive, subjective cognitive and neurophysiological.

The purpose of this study was to evaluate cognitive fatigue in patients with a mild form of multiple sclerosis (MS) from three different approaches: objective cognitive, subjective cognitive and neurophysiological. Objective cognitive fatigue was assessed with tasks demanding sustained attention, processing speed and working memory. Subjective cognitive fatigue was assessed with self-reported values. Neurophysiological assessment included measurements of event-related potentials (ERP), namely contingent negative variation (CNV) and P3. Alongside these measurements, the participants evaluated their quality of life. 20 MS patients and 20 matched healthy controls (HC) participated in the study. The two study groups did not differ from one another in a brief cognitive screening found to be sensitive to cognitive deficits in MS. Neuropsychological tests revealed some signs of objective cognitive fatigue in both study groups and possible signs of MS-related cognitive fatigue. In both study groups, this manifested as declining cognitive performance within the Paced Auditory Serial Addition Task (PASAT), and in the MS patients as longer reaction times during the last task in the study procedure. At the same time as the reaction times were longer, the analysis of ERPs revealed smaller CNV amplitudes in the frontal electrode sites in the MS group. Moreover, the P3 Go latencies were shorter and the P3 No-Go amplitudes were smaller at the Cz. These results for the MS patients indicated atypical preparation processes when focusing attention in the frontal brain area and attenuated resource allocation for No-Go stimuli. The ERP measurements did not reveal signs of objective cognitive fatigue. Both study groups reported cognitive fatigue caused by cognitive strain. After resting for half an hour, the HCs reported better recovery from subjective cognitive fatigue than the MS patients. The objective neuropsychological results were not associated with the ERP measurements. The subjective evaluations of cognitive fatigue were not associated with the objective cognitive or europhysiological results. Perceived quality of life was rated lower by the MS patients than HCs. The MS patients’ quality of life ratings were associated with their ratings of subjective cognitive fatigue. This may affect the MS patients’ idea of their working ability. The results indicate that cognitive fatigue is present in healthy people as well as in patients with MS. It seems that objective cognitive and subjective cognitive fatigue are separate symptoms and that subjective cognitive fatigue does not necessarily affect objective cognitive performance. MS seems to slow down recovery from subjective cognitive fatigue.

More information

Sanna Liuha
sanna.liuha@ksshp.fi
+ 358 14 269 2327
Filed under: