Motor neurone disease

Summary

Introduction

Motor Neurone Disease (MND), is a terminal, progressive neurodegenerative disease of the central nervous system. The most common form of MND is amyotrophic lateral sclerosis (ALS) involving both upper and lower motor neurones (UMNs, LMNs). Less common are primary lateral sclerosis (involving only UMNs) progressive muscular atrophy (involving only LMNs) and progressive bulbar palsy (PBP) where there is predominant involvement of the motor systems of the brainstem (Leigh & Ray-Chaudhuri, 1994). Peak age at onset is in the sixth decade of life. Incidence is around 1–2: 100 000 per year and prevalence 5–6:100 000. Median survival in ALS is 3.5 years from diagnosis, death commonly resulting from respiratory failure. Disease progression is generally variable but prognosis is poorest in those presenting with bulbar signs (about 25% of cases). Typically the disease presents with limb muscle weakness. Overall 90–95% of cases are sporadic, but 5–10% are familial in nature. At present there is no cure for MND. However the glutamate release antagonist, riluzole, has been shown to improve survival at 18 months (Lacomblez et al., 1996).

Psychological research concerning people with MND has predominantly involved investigations of the neuropsychological profile associated with ALS and of emotional and psychosocial issues (Goldstein & Leigh, 1999).

Neuropsychological aspects of MND

Increasing evidence that MND involves extra-motor cerebral regions is provided by findings of mild cognitive impairment occurring in up to 35–40% of non-demented patients with ALS, and by reports that a fronto-temporal dementia may also be seen in ~5% of sporadic cases (see ‘Dementias’).