Sansuthan Paramanathan1, Hatice Tankisi2, Henning Andersen3, Anders Fuglsang-Frederiksen1. 1. Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark. 2. Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: hatitank@rm.dk. 3. Department of Neurology, Aarhus University Hospital, Aarhus, Denmark.
Abstract
OBJECTIVE: This study quantifies functioning axons and reinnervation by applying two methods multiple point stimulation (MPS) MUNE, and motor unit number index (MUNIX), in patients with acute- and chronic inflammatory demyelinating polyneuropathy (AIDP, CIDP). METHODS: Nineteen patients with inflammatory demyelinating polyneuropathy (eleven AIDP and eight CIDP) were prospectively included. MPS MUNE and MUNIX examinations on the thenar muscle group by stimulating the median nerve were applied on all patients. Motor unit size was calculated as single motor unit potential (sMUP) and motor unit size index (MUSIX). The results were compared with twenty healthy subjects. RESULTS: In AIDP patients mean MPS MUNE (106) and MUNIX (80) were lower than control MPS MUNE (329) and MUNIX (215) (p<0.001). In CIDP patients both MPS MUNE (88) and MUNIX (67) were lower than controls (p<0.001). In CIDP patients sMUP (63) and MUSIX (90) were higher than control sMUP (35) and MUSIX (58) (p<0.05 and p<0.01). When AIDP and CIDP groups were combined the sensitivity for MPS MUNE and MUNIX were 89.5% and 68.4%, respectively. CONCLUSIONS: Decreased MPS MUNE and MUNIX suggest presence of axonal loss or loss of functioning axons in AIDP and CIDP. Increased motor unit size in CIDP patients indicates compensatory reinnervation. Moreover, both MPS MUNE and MUNIX can discriminate between disease versus non-disease. SIGNIFICANCE: Estimation of the number and the average size of motor units may have clinical value for the assessment of axonal loss or loss of functioning axons in patients with AIDP and CIDP.
OBJECTIVE: This study quantifies functioning axons and reinnervation by applying two methods multiple point stimulation (MPS) MUNE, and motor unit number index (MUNIX), in patients with acute- and chronic inflammatory demyelinating polyneuropathy (AIDP, CIDP). METHODS: Nineteen patients with inflammatory demyelinating polyneuropathy (eleven AIDP and eight CIDP) were prospectively included. MPS MUNE and MUNIX examinations on the thenar muscle group by stimulating the median nerve were applied on all patients. Motor unit size was calculated as single motor unit potential (sMUP) and motor unit size index (MUSIX). The results were compared with twenty healthy subjects. RESULTS: In AIDPpatients mean MPS MUNE (106) and MUNIX (80) were lower than control MPS MUNE (329) and MUNIX (215) (p<0.001). In CIDPpatients both MPS MUNE (88) and MUNIX (67) were lower than controls (p<0.001). In CIDPpatients sMUP (63) and MUSIX (90) were higher than control sMUP (35) and MUSIX (58) (p<0.05 and p<0.01). When AIDP and CIDP groups were combined the sensitivity for MPS MUNE and MUNIX were 89.5% and 68.4%, respectively. CONCLUSIONS:Decreased MPS MUNE and MUNIX suggest presence of axonal loss or loss of functioning axons in AIDP and CIDP. Increased motor unit size in CIDPpatients indicates compensatory reinnervation. Moreover, both MPS MUNE and MUNIX can discriminate between disease versus non-disease. SIGNIFICANCE: Estimation of the number and the average size of motor units may have clinical value for the assessment of axonal loss or loss of functioning axons in patients with AIDP and CIDP.