How is primary lateral sclerosis (PLS) diagnosed?

Updated: Sep 06, 2019
  • Author: Carmel Armon, MD, MSc, MHS; Chief Editor: Nicholas Lorenzo, MD, MHCM, CPE, FAAPL  more...
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As previously mentioned, patients with primary lateral sclerosis (PLS) occasionally have mild, nonspecific, and nonprogressive findings of denervation on electrodiagnostic testing. [11] The severity of the denervation and reinnervation does not resemble that seen in ALS and does not justify these patients' being classified as having ALS.

Whether serial electromyography (EMG) has a role in the diagnosis of PLS is uncertain; EMG might be used to look for the evolution of lower motor neuron findings in the absence of clinical evidence to suggest a change into ALS, but the clinical implication would be uncertain.

Despite the availability of supporting imaging and clinical neurophysiologic features, described best in patients with established disease, the initial diagnosis of PLS is usually made on clinical grounds.

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