Certified Polysomnographic Technician (CPSGT) Practice Exam 2025 - Free CPSGT Practice Questions and Study Guide

Cataplexy is specifically characterized by a sudden loss of muscle tone that occurs in response to strong emotions, such as laughter, excitement, or anger. This phenomenon can lead to a physical collapse or the inability to maintain posture, while the individual remains fully conscious and aware of their surroundings. This loss of muscle tone is a hallmark symptom associated with narcolepsy and is distinctly different from other conditions that involve muscle movements or wakefulness.

In contrast, sudden muscle spasms refer to involuntary contractions of muscles, which do not align with the characteristics of cataplexy. Repetitive limb movements are more indicative of other disorders, such as restless legs syndrome or periodic limb movement disorder, rather than the emotional trigger and muscle tone loss seen in cataplexy. Prolonged periods of wakefulness do not correlate with cataplexy either, as cataplexy occurs suddenly and is usually brief, especially in the context of an underlying condition like narcolepsy where excessive daytime sleepiness is prevalent. Understanding these distinctions helps clarify why the loss of muscle tone during strong emotions is the defining characteristic of cataplexy.