The value of muscle exercise in patients with amyotrophic lateral sclerosis

Abstract

The role of physical activity for patients with amyotrophic lateral sclerosis (ALS) is controversial. Twenty-five ALS patients were randomized to receive a moderate daily exercise program (n=14) or not to perform any physical activity beyond their usual daily requirements (n=11).

At baseline and after 3, 6, 9 and 12 months, patients were assessed by manual muscle strength testing, the Ashworth spasticity scale, ALS functional rating scale (FRS), fatigue severity scale, a visual analogue scale for musculoskeletal pain and the quality-of-life scale (SF-36).

At 3 months, patients who performed regular exercise showed less deterioration on FRS and Ashworth scales, but not on other parameters. At 6 months, there was no significant difference between groups, although a trend towards less deterioration in the treated group on most scales was observed. At 9 and 12 months, there were too few patients in each group for statistical evaluation.

Our results show that a regular moderate physical exercise program has a short-lived positive effect on disability in ALS patients and should be recommended.

Introduction

The question of whether regular exercise is to be recommended or avoided in patients with amyotrophic lateral sclerosis (ALS) is still controversial [1]. Moderate regular exercise is advocated in the management of many neuromuscular diseases [2], [3], [4], [5], [6], allowing weak muscles to increase their mitochondrial content and enhance muscle blood flow and strength, to develop better exercise endurance and to avoid complications, such as frozen shoulder and musculoskeletal pain [7].

However, patients with ALS are frequently recommended to avoid physical activity in order to preserve their muscle strength and minimize overwork muscle damage. This recommendation is based mainly on epidemiological studies showing a higher incidence of ALS in patients performing intense physical activity at work or for leisure before onset of the disease [8], [9], [10], although other studies do not confirm this observation [11], [12]. The role of physical activity after onset of the disease was not addressed systematically in ALS.

In the transgenic mice model of ALS, physical activity was not detrimental in terms of survival [13]. In a single published patient, a resistance exercise program led to improvement of strength in most tested muscle groups [14]. In another single case description, exercise seemed to have had a favorable effect on muscles with upper motor neuron weakness, but did not seem to benefit muscles with lower motor neuron dysfunction [15]. In few ALS patients with respiratory insufficiency, physical exercise was shown recently to slow the clinical deterioration as measured by the Norris scale and by respiratory function tests [16].

Repetitive range-of-motion exercise is able to decrease spasticity [17], [18]. As spasticity can significantly impair the motor function of ALS patients, this type of exercise should have a positive influence on patients' disability.

Fatigue is a common symptom in ALS and is caused mainly by impaired activation of the muscle fibers of enlarged motor units [19], it has a significant negative impact on the quality-of-life of patients with ALS. In normal individuals, exercise increases the efficiency of the neuromuscular system and diminishes fatigue [20].

Pain is common late in the course of ALS and is caused mainly by muscle cramping or secondary to degenerative joint changes due to prolonged immobility [21]. Regular exercise decreases pain of musculoskeletal origin [22].

In the absence of a cure, one of the main aims in the management of patients with ALS is to maintain a reasonable quality-of-life. In healthy persons, there is a positive relationship between physical activity and quality-of-life [23].

The purpose of the present study was to determine the effect of moderate regular exercise under professional guidance on parameters of motor deficit, disability, fatigue, musculoskeletal pain and perceived quality-of-life.