The Development of the Edinburgh ALS Cognitive Screen

Abstract

Motor Neurone Disease, (MND) is the name used within the United Kingdom referring to a group of conditions that affect the upper and/or lower motor neurones. Originating in the motor cortex, the upper motor neurones, (UMN), form synapses with the lower motor neurones (LMN) in the motor nuclei of the brainstem and spinal cord. (Kiernan, Vucic & Cheah, 2011). Lower motor neurones innervate the muscles causing a spinal reflex arc. This motor contraction allows in health, movement required by the autonomic and voluntary nervous systems to innervate the muscle groups responsible for breathing, swallowing, communication and movement. Degeneration causes the reflex arc to break, and, in duration of time, the muscles fatigue, weaken and eventually paralyse. Clinical presentation is segmental before eventually becoming widespread (Kiernan et al., 2011). Seventy per cent of patients present with limb onset versus twenty-five per cent with bulbar onset, (dysarthria and dysphagia) and five per cent with trunk or respiratory involvement (Kiernan et al., 2011). Under the umbrella of MND there are three main subtypes of disorders all with differing neuro- pathophysiologies. Amyotrophic Lateral Sclerosis, (ALS), involves clear clinical signs of dysfunction of both upper and lower motor neurones. Primary Lateral Sclerosis (PLS) affects the upper motor neurones only, characterised by spastic quadriparesis (spasms in all limbs), inappropriate emotions and spastic dysarthria, whilst Progressive Muscular Atrophy, (PMA), predominantly affects the lower motor neurones causing muscle wasting weakness (Kiernan et al., 2011).