Does the way my body functions change differently in amyotrophic lateral sclerosis over time?

In amyotrophic lateral sclerosis (ALS), your body functions change progressively as the disease affects nerve cells that control movement, breathing, speech, and swallowing. The rate and pattern of change vary from person to person, but research shows that functional decline can be tracked using tools like the ALS Functional Rating Scale-Revised (ALSFRS-R) ³⁵. Over time, you may notice increasing difficulty with fine motor tasks, walking, speaking, swallowing, and breathing. These changes often require adjustments in daily life and medical care.

What the research says

Studies show that ALS progression affects multiple body systems in distinct ways. A network meta-analysis of 109 trials found that the ALSFRS-R score, which measures function in bulbar (speech/swallowing), fine motor, gross motor, and respiratory domains, declines over time, and certain treatments may slow this decline ³. Another analysis of pooled trial data used Shannon entropy to track how function changes across these four domains. It found that in the fine motor domain, the placebo group reached peak entropy (indicating maximum variability before functional loss) at month 8, while the active treatment group did not peak until month 13, suggesting a delay in functional decline ⁵.

Respiratory function also changes over time. A study of early ALS patients found that their circadian rhythm, measured by melatonin onset, was shifted earlier compared to healthy controls, and this shift was linked to later respiratory symptoms ². Additionally, a post-hoc analysis of masitinib treatment reported that long-term survivors (5 years or more from symptom onset) had a delay in needing mechanical assistance such as ventilation or a wheelchair, suggesting that some treatments may slow the progression of functional loss ⁷.

As ALS advances, many people require durable medical equipment (DME) like wheelchairs, non-invasive ventilation, or feeding tubes. In a clinical trial for reldesemtiv, 34.4% of participants already used DME at the start, and 47.1% of those who completed 24 weeks initiated new DME items, indicating that functional decline often leads to increased reliance on assistive devices ⁴.

Cognitive and communication changes also occur. A meta-analysis found that speech features (like nasality and voicing) correlate with ALS severity, meaning that as the disease progresses, speech becomes more affected ⁸. Furthermore, embodied cognition research suggests that ALS can affect the connection between body and mind, impacting perception and reasoning even without obvious cognitive deficits ¹¹.

What to ask your doctor

• How can I track changes in my motor, bulbar, and respiratory function over time?
• What treatments or therapies might help slow functional decline in my specific ALS type?
• When should I consider using durable medical equipment like a wheelchair or breathing support?
• Are there any clinical trials or new medications that could help manage my symptoms?
• How can I monitor changes in my speech and swallowing, and what support is available?