Upper motor neuron involvement is demonstrable pathologically even in ALS cases with only lower motor neuron involvement clinically (Brownell et al., 1970; Ince et al., 2003), and its detection alongside the more typical lower motor neuron involvement in ALS is a cornerstone of diagnostic certainty.
Upper and lower motor neuron involvement is found at post-mortem in nearly all cases with ALS, but upper motor neuron signs may be difficult to detect clinically (Swash, 2012).
Amyotrophic lateral sclerosis (ALS) with both upper and lower motor neuron involvement is the most common presentation, accounting for more than 75%% of cases with motor neuron disease [ 1, 2].
As far as upper motor neuron involvement is concerned, transcranial magnetic stimulation (TMS) and its variants are useful tools to evaluate motor cortical and corticospinal dysfunction and discriminate between ALS and mimic disorders.
Therefore, between-study differences in the subjects' tendency to movement imagination may be an additional cause for whether or not primary motor cortex involvement is found in different studies.
14 15 25 The Oxford Feeding Study of 271 children with OPD, found those with more extensive motor involvement, that is, quadriplegia and dyskinesia, were most likely to have difficulties with swallowing and articulation, based on parent report.
A very rare variant known as primary lateral sclerosis demonstrates only upper motor neuron involvement clinically, with characteristically long survival, and those with 'pure' lower motor neuron involvement are also typically slower in rate of progression (Turner et al., 2003).
However, because clinical evidence of upper motor neuron involvement was restricted to the lower limbs, the patient only met diagnostic criteria for clinically possible motor neuron disease.
Also, further clinical or neurophysiological signs of lower motor neuron involvement were not evident in our cases.
Beyond its role to exclude several "ALS-mimick" syndromes [ 1], abnormalities suggestive of upper motor neuron involvement are sometimes detected.
