RT Journal Article
SR Electronic
T1 Pattern of paresis in ALS is consistent with the physiology of the corticomotoneuronal projections to different muscle groups
JF Journal of Neurology, Neurosurgery & Psychiatry
JO J Neurol Neurosurg Psychiatry
FD BMJ Publishing Group Ltd
SP 991
OP 998
DO 10.1136/jnnp-2020-323331
VO 91
IS 9
A1 Albert C Ludolph
A1 Susanne Emilian
A1 Jens Dreyhaupt
A1 Angela Rosenbohm
A1 Alexander Kraskov
A1 Roger N Lemon
A1 Kelly Del Tredici
A1 Heiko Braak
YR 2020
UL http://jnnp.bmj.com/content/91/9/991.abstract
AB Objective A recent neuroanatomical staging scheme of amyotrophic lateral sclerosis (ALS) indicates that a cortical lesion may spread, as a network disorder, both at the cortical level and via corticofugal tracts, including corticospinal projections providing direct monosynaptic input to α-motoneurons. These projections are involved preferentially and early in ALS. If these findings are clinically relevant, the pattern of paresis in ALS should primarily involve those muscle groups that receive the strongest direct corticomotoneuronal (CM) innervation.Methods In a large cohort (N=436), we analysed retrospectively the pattern of muscle paresis in patients with ALS using the UK Medical Research Council (MRC) scoring system; we subsequently carried out two independent prospective studies in two smaller groups (N=92 and N=54).Results The results indicated that a characteristic pattern of paresis exists. When pairs of muscle groups were compared within patients, the group known to receive the more pronounced CM connections was significantly weaker. Within patients, there was greater relative weakness (lower MRC score) in thumb abductors versus elbow extensors, for hand extensors versus hand flexors and for elbow flexors versus elbow extensors. In the lower limb, knee flexors were relatively weaker than extensors, and plantar extensors were weaker than plantar flexors.Conclusions These findings were mostly significant (p<0.01) for all six pairs of muscles tested and provide indirect support for the concept that ALS may specifically affect muscle groups with strong CM connections. This specific pattern could help to refine clinical and electrophysiological ALS diagnostic criteria and complement prospective clinicopathological correlation studies.