Table 1.

Non-motor symptoms explored in this study

Symptom	Prevalence	Features of symptom
Pain	50–85%10	Pain became more problematic over time and reduced quality of life.10 May be responsive physical therapy11 and pharmacological intervention.12
Sleep	Sleep disturbance and poor quality sleep are frequently reported but exact prevalence depends on the specific sleep-related issue49	Sleep quality, length of sleep and rapid eye movement duration can be improved in people with motor neuron disease utilizing non-invasive ventilation.13
Fatigue	Up to 44% of person with motor neuron disease	Co-occurs with depression in 15% of individuals.14 Sleepiness is a key aspect of fatigue in people motor neuron disease, along with reduced alertness, loss of stamina and lack of energy.7
Neuropsychiatric	19.7%, 70% of which were mood disorders and 31.67% neurotic disorders (inclusive of anxiety, stress-related and somatoform disorders)15	Elevated in comparison with rates in the general population, 6.9% of whom fulfil diagnostic thresholds for major depressive disorder and 14% an anxiety disorder.50,51
Cognitive complaints	Experienced by 30–50% of person with motor neuron disease	Detrimental to an individual’s quality of life and prognosis.52,53
Behaviour change	28% indicated abnormally high levels of apathy54 50% experience emotional lability54	Apathy is the most commonly reported behavioural change, measured with the Dimensional Apathy Scale.55 Emotional lability is characterized by some changes in emotionality and emotion regulation.54
Problematic saliva	37.5% of people with motor neuron disease56	Problematic saliva production and handling in motor neuron disease is characterized by thickened saliva and sialorrhoea. Detrimental to an individual’s well-being, increase the risk of respiratory complications and exacerbate dysarthria.57
Gastrointestinal	16–83%, depending on the specific symptom7	Symptoms such as constipation, nausea, vomiting, acid reflux or excessive flatulence.58 May occur as a response to interventions (particularly new drug treatments or non-invasive ventilation), secondary to increasingly physical disability or as indicative of wider nervous system degeneration.7,59
Sexual dysfunction	Interest in sex reported to decrease 28% after an motor neuron disease diagnosis60	Not directly affected by motor neuron disease but the impact of an motor neuron disease diagnosis on sexuality, intimacy and libido remain relevant to exploring the a more holistic impact of non-motor symptoms of the condition on the individual61 Changes in sexual behaviour can have on an individual’s quality of life61,62; sexuality is often not discussed in routine clinical consultations or included in research design.