Quantifying Cognitive Fatigue in Multiple Sclerosis using P300 Evoked Potentials (P4.398)

Objective: To develop measures using P300 evoked potentials to quantify cognitive fatigue. Background: Cognitive Fatigue plays a significant role in Multiple Sclerosis (MS) related impairment. Not many objective measures are available to quantify cognitive fatigue. The tests currently used to detect cognitive fatigue are long and tedious. Design/Methods: 50 patients with MS satisfying revised 2010 McDonald criteria attending the OPD in the Institute of Neurology, Chennai were recruited. Short and long versions of the Serial Addition Test (SAT), Symbol Digit Modalities Test (SDMT), Stroop test were used to detect cognitive fatigue. P300 latency and amplitude were measured in all subjects for 50 and 150 rare stimuli using the odd-ball paradigm. Latency ratio (P300L150/P300L50)and amplitude ratio (P300A50/P300A150) were then calculated. Logistic regression models were used to obtain the area under receiver operating characteristic curve(AUC) for these measures. Results: Clinical tests revealed that 46%(n = 23) of subjects had a significant cognitive fatigue. Both P300L150/P300L50and P300A50/P300A150 had a high predictive accuracy with AUC of 0.863 and 0.819 respectively in detecting cognitive fatigue. Conclusions: The electrophysiological measures used in this study have a high predictive accuracy to quantify cognitive fatigue. These measures can thus be used as quick and efficient tools in detecting cognitive fatigue in MS patients in comparison to lengthier and cumbersome clinical tests. Disclosure: Dr. Chinnadurai has nothing to disclose. Dr. Srinivasan has nothing to disclose. Dr. Ranganathan has nothing to disclose. Dr. Kesavamurthy has nothing to disclose.