O-22 Multiple point stimulation MUNE in ALS: Towards a faster modification

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Background Multiple point stimulation (MPS) is a well-established motor unit number estimate (MUNE) method that can be used in all EMG machines, but it is time-consuming. We investigated whether a faster modification of MPS using 5 surface motor unit action potentials (sMUAP) had similar reproducibility, sensitivity and specificity as 10. Material and methods Twenty-two motor neuron disease patients and 20 healthy controls were prospectively examined by two physicians twice in the thenar muscles. Results A total of 168 MPS MUNE recordings were obtained. Mean MUNE was significantly lower in patients in contrast to the controls, whether using 5 [53 ± 55 (1–170) versus 150 ± 64 (51–325), p 0.05) were found between mean MUNE obtained from 5 or 10 sMUAP in both patients and controls. Intra-rater coefficient of variation (CV) for patients (17% versus 15%) and controls (16% versus 13%) and inter-rater CV for patients (25% versus 24%) did not differ between 5 and 10 sMUAP (p > 0.05), whereas inter-rater CV was higher for 5 sMUAP in controls (21% versus 16%, p = 0.004). An excellent intraclass correlation coefficient (⩾0.78) was found, sampling either 5 or 10 sMUAP, for both groups. Receiver operating characteristic (ROC) curves collecting 5 or 10 sMUAP showed excellent accuracy in distinguishing between patients and controls. Conclusions The faster modification of MPS by sampling 5 sMUAP had similar reproducibility, sensitivity and specificity as 10, and may be suggested in future research and clinical practice.