# Beyond motor neurons: autonomic dysfunction and ECG findings in adults with 5q-spinal muscular atrophy

## TL;DR

Adults with 5q-spinal muscular atrophy experience significant autonomic symptoms and ECG abnormalities, which affect their quality of life.

## Contribution

This study is the first to systematically evaluate autonomic dysfunction and ECG findings in adults with SMA and link them to quality of life.

## Key findings

- SMA patients had significantly worse autonomic function scores compared to healthy controls.
- Autonomic symptoms correlated negatively with quality of life and were more severe in patients with more severe SMA.
- ECG abnormalities were more common in non-ambulatory patients and those with more severe SMA types.

## Abstract

5q-Spinal muscular atrophy (SMA) is a lower motor neuron disease. However, peripheral organ involvement might contribute to its complex clinical picture, especially in severe forms. This study evaluated frequency and characteristics of autonomic symptoms, prevalence of electrocardiographic (ECG) abnormalities, and the impact of autonomic dysfunction on quality of life (QoL) in adults with SMA.

Autonomic function was assessed using the SCales for Outcomes in PArkinson’s disease-Autonomic Dysfunction (SCOPA-AUT). 12-Lead ECG was recorded. The Hammersmith Functional Motor Scale Expanded (HFMSE), Revised Upper Limb Module (RULM), Fatigue Severity Scale (FSS), Beck Depression Inventory (BDI), and 36-Item Short Form Health Survey (SF-36) were collected to assess motor function, fatigue, depression, and QoL.

Forty-three SMA patients (23 males; mean age: 37.6 ± 14.1 years) and forty-three age- and sex-matched healthy controls were included. Compared to healthy controls, SMA patients scored worse on gastrointestinal domain (2.9 ± 2.9 vs. 1.1 ± 1.5, p < 0.001) and in total SCOPA-AUT score (9.8 ± 7.3 vs. 5.7 ± 4.4, p = 0.002). More severely affected patients reported a greater burden of autonomic symptoms compared to those with milder phenotypes. Burden of autonomic symptoms correlated with QoL (ρ = − 0.33, p = 0.028). The presence of major ECG abnormalities showed a negative correlation with SMA type (ρ = − 0.39, p = 0.027), age at the time of testing (ρ = − 0.45, p = 0.009), and ambulatory status (ρ = − 0.39, p = 0.027).

Adults with SMA demonstrate a substantial burden of autonomic symptoms, especially those with more severe disease. This burden significantly compromises patients’ QoL. Further studies are needed to better understand autonomic dysfunction in this population.

The online version contains supplementary material available at 10.1007/s00415-025-13446-w.