Fluctuation of primary motor cortex excitability during cataplexy in narcolepsy

Study on the Diagnostic Value of Neuroelectrophysiological Examination in Patients with Amyotrophic Lateral Sclerosis

Objective

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease with unknown causes involving upper and lower motor neurons. Our study aimed to explore the diagnostic value of neuroelectrophysiological examination in patients with amyotrophic lateral sclerosis.

Methods

A total of 64 patients admitted to our hospital from January 2014 to December 2020 were selected as ALS group. Additionally, 64 normal healthy people in the same period were selected as the control group. Electrophysiological tests were performed on all personnel involved in the study, and the results and parameter changes of different personnel were compared and analyzed.

Results

There was a statistical difference between the EMG data of clinically confirmed ALS and the proposed ALS and possible ALS (p < 0.05). The abnormality of confirmed ALS was particularly obvious, and the overall abnormal rate of EMG in ALS was 85%. The CMCT of the upper and lower limbs of clinically diagnosed ALS, suspected ALS, and possible ALS were longer than that of the normal group (p < 0.05). There was no significant statistical difference between clinically diagnosed ALS and suspected ALS (p > 0.05), and there was a difference between clinically diagnosed ALS and possible ALS (p < 0.05). In ALS group, the frequency of F wave decreased, which may be related to the involvement of F wave conduction pathway and the degree of lower motor neuron involvement (p < 0.05). In addition, the amplitudes of F and H waves increased, which was related to the involvement of upper motor neurons (p < 0.05). In ALS group, SCV was hardly involved, and CMAP decreased significantly, which was positively correlated with the degree of muscular atrophy and muscle strength decline (p < 0.05). The sensitivity of electrophysiological detection was 76.56%, the specificity was 78.33%, and the AUC was 0.8578.

Conclusion

Patients with clinically suspected ALS should undergo electrophysiological testing as soon as possible, which is conducive to the early diagnosis and differential diagnosis of ALS. This trial is registered with ChiCTR2100046535.

Clinical Characteristics of Cataplectic Attacks in Type 1 Narcolepsy

PURPOSE OF REVIEW

Narcolepsy is a central disorder of hypersomnolence with symptoms of excessive daytime sleepiness, sleep paralysis, and cataplexy. Cataplexy is the sudden loss of muscle tone in either the face, neck, trunk, and/or limbs, leading to a loss of voluntary muscle control. This article reviews recent research on the clinical characteristics of cataplexy.

RECENT FINDINGS

Longitudinal research in adults suggests that there may be a remission of cataplectic severity after symptom stabilization. First-line treatment options for cataplexy include sodium oxybate and pitolisant, with many drugs such as AXS-12, FT218, and JZP258 under investigation. Patients with cataplexy reported greater limitations of daily activities such as driving and exercise compared to patients without cataplexy. Cataplexy remains a challenge for children and adults with narcolepsy and can interfere with daily activities. There is no cure for narcolepsy, but cataplexy can be well-managed with current and promising new treatment options on the horizon.

Therapy for Cataplexy

Purpose of the review

Cataplexy, an involuntary loss of muscle activity triggered by strong emotions is the most impressive symptom in narcolepsy. This review gives an overview of the current understanding of cataplexy and its available treatment options.

Recent findings

With the discovery of hypocretin/orexin, the understanding of the pathophysiology of cataplexy advanced in the past decades. In the recent years, with the development of new anticataplectic agents (e.g., Pitolisant) symptomatic treatment of cataplexy has further improved. Abrupt cessation of anticataplectic medication especially antidepressants increase the risk of status cataplecticus, a virtually continuous series of long-lasting cataplectic attacks.

Summary

Cataplexies still remain an under-recognized phenomenon due to missing diagnostic measures. Treatment for cataplexy still remains symptomatic but new agents with better tolerability and usability are continuously developed. New therapeutic actions either targeting the autoimmune mechanisms underlying orexin cell death or substituting orexin action are promising treatments for the near future.