Okhovat AA, Advani S, Ziaadini B, Panahi A, Salehizadeh S, Nafissi S, Haghi Ashtiani B, Rajabally YA, Fatehi F. The value of MUNIX as an objective electrophysiological biomarker of disease progression in CIDP.
Muscle Nerve 2022;
65:433-439. [PMID:
35040150 DOI:
10.1002/mus.27498]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 12/31/2021] [Accepted: 01/09/2022] [Indexed: 11/06/2022]
Abstract
INTRODUCTION/AIMS
Objective outcome measures to monitor treatment response and guide treatment are lacking in chronic inflammatory demyelinating polyneuropathy (CIDP). We aimed to evaluate the motor unit number index (MUNIX) as an outcome measurement in patients with CIDP and investigate the correlation of MUNIX with functional and standard electrodiagnostic tests in a single follow-up study.
METHODS
We evaluated MUNIX of the abductor pollicis brevis (APB), abductor digiti minimi (ADM), and tibialis anterior (TA) muslces bilaterally. Muscle force was assessed by Medical Research Council sumscores (MRCSS). Functional measures used were the Overall Neuropathy Limitation Score (ONLS) and the Rasch-built Overall Disability Scale (R-ODS) at baseline and after six months of treatment. Standard electrophysiology was evaluated by the Nerve Conduction Study Score (NCSS).
RESULTS
Twenty patients were included at baseline, and 16 completed the follow-up study. Significant correlations were found between the MUNIX sumscore and both MRCSS and NCSS at baseline, between both the pinch strength and grip and upper limb MUNIX at baseline and follow-up, and between MUNIX of TA and both lower limb MRCSS with lower limb ONLS at baseline and follow-up. Significant correlations also were found between MUNIX sumscore change and MRCSS change, R-ODS change, and ONLS change.
DISCUSSION
MUNIX changes correlated with strength and electrophysiological improvements in CIDP patients. This suggests that MUNIX may represent a useful objective biomarker for patient follow-up.
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