Table 1.

Electrophysiologic Studies in ALS2-Related Disorder by Phenotype

StudyPhenotype
IAHSPJPLSJALS
MEP Severe dysfunction of the corticospinal tracts 1NAAbsent or ↓ action potential, suggesting dysfunction of corticospinal tracts 2
SSEP Normal in early stages; abnormal in later stagesPoorly configured; normal central conductionNA
EMG No signs of denervationNo signs of denervationSigns of denervation
TCMS No motor evoked potentials

EMG = electromyography; IAHSP = infantile-onset ascending hereditary spastic paralysis; JALS = juvenile amyotrophic lateral sclerosis; JPLS = juvenile primary lateral sclerosis; MEP = motor evoked potentials; NA = not available; SSEP = somatosensory evoked potentials; TCMS = transcranial magnetic stimulation

1.

Primitive, pure degeneration of the upper motor neurons

2.

From: ALS2-Related Disorder

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