J Korean Med Sci.  2010 Sep;25(9):1359-1363. 10.3346/jkms.2010.25.9.1359.

Motor Unit Number Estimation in Evaluating Disease Progression in Patients with Amyotrophic Lateral Sclerosis

• Ahn SW
• Kim SH
• Oh DH
• Kim SM
• Park KS
• Hong YH
• Kwon OS
• Sung JJ
• Lee KW

• KMID: 1785917
• DOI: http://doi.org/10.3346/jkms.2010.25.9.1359

Abstract

We investigated the availability of motor unit number estimation (MUNE) as a quantitative method to assess the severity and clinical progression of amyotrophic lateral sclerosis (ALS). The 143 ALS patients were evaluated by statistical MUNE and the revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R). By using mean values of MUNE according to disease duration, regression equation between mean MUNE and disease duration was presented as a formula. The individual MUNE ratio was calculated by dividing individual MUNE value by mean MUNE value. All patients were classified into 2 groups (MUNE ratio <1 vs. MUNE ratio > or =1) according to the MUNE ratio. Comparison between the 2 groups revealed that the patients in MUNE ratio <1 group or MUNE ratio > or =1 group were respectively assigned to rapid progression or slow progression. We recommended informative mean values of MUNE and best regression equation in ALS patients according to disease duration. These values allow us to evaluate the severity and rapidity of progression in ALS.

Keyword

Amyotrophic Lateral Sclerosis; Motor Unit Number Estimation

MeSH Terms

Action Potentials/physiology
Adult
Age of Onset
Aged
Amyotrophic Lateral Sclerosis/*diagnosis/physiopathology
Data Interpretation, Statistical
Disease Progression
Female
Humans
Male
Middle Aged
Motor Neurons/pathology/*physiology
Muscle Fibers, Skeletal/physiology
Severity of Illness Index

Figure

• 

  Fig. 1 Correlations of size-weighted MUNE with disease duration (A), disease duration with ALSFRS-R (B), size-weighted MUNE with ALSFRS-R (C), and MUNE ratio with rate of progression by ALSFRS-R (D) were statistically significant (P value <0.01). MUNE, motor unit number estimation; ALSFRS-R, revised amyotrophic lateral sclerosis functional rating scale; MUNE ratio=(individual SW-MUNE)/(estimated mean SW-MUNE using regression equation).

• 

  Fig. 2 MUNE gradually decreases as disease advanced in ALS, and size-weighted MUNE shows the most significant correlation with disease duration. From mean disease duration and mean SW-MUNE, regression equation was analyzed (Estimated mean SW-MUNE=48.03-0.85×[disease duration]). P-MUNE, Program determined MUNE; NW-MUNE, number-weighted MUNE; SW-MUNE, Size-weighted MUNE ALSFRS-R, revised amyotrophic lateral sclerosis functional rating scale.

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