Naoum Issa1, Elena Goicoechea1, Serdar Aydin1, Sean Smith3, Nathan Carberry4, Doreen Ho5, Mark Garret6, Avinash Moses2, Betty Soliven2, Kourosh Rezania1
1Neurology, University of Chicago, 2University of Chicago, 3Neurology, Washington University, 4University of Miami, 5MGH, 6Dartmouth University
Objective:
We investigated whether intermuscular coherence in the beta-gamma (20-40 Hz) frequency range (IMCβγ) can serve as a biomarker for PLS.
Background:
Primary lateral sclerosis (PLS) is a sporadic neurodegenerative disorder characterized by progressive degeneration of upper motor neurons (UMNs). It represents one extreme of the motor neuron disease spectrum, with amyotrophic lateral sclerosis (ALS) being the most prevalent condition within this category. In its early stages, PLS must be distinguished from an UMN predominant variant of ALS. A diagnosis of PLS has important prognostic implications, as PLS has slower disease progression and significantly longer survival than ALS. Currently, there is a need for a widely accessible neurophysiological biomarker that can detect and monitor UMN dysfunction.
Design/Methods:
IMCβγ was evaluated in upper and lower limb muscle pairs in 21 individuals with PLS along with 42 age- and sex-matched neurotypical control subjects.
Results:
IMCβγ was significantly lower in PLS patients across all muscle pairs. Area under the receiver-operating characteristic curve ranged between 0.71 and 0.77 for differentiating PLS from neurotypical control subjects based on measurements in a single limb. Using an abnormal coherence measurement in any two limbs as a diagnostic test for PLS, test sensitivity was 0.76, specificity was 0.86, and accuracy was 0.83.
Conclusions:
IMCβγ measured in the arms legs helps distinguish PLS patients from neurotypical control subjects, supporting its potential as an accessible biomarker of UMN dysfunction.
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