Which muscles are monitored with EMG leads during the MSLT?

During the Multiple Sleep Latency Test (MSLT), the specific muscles monitored with EMG leads are the chin and submentalis muscles. This choice is correct because these muscles are crucial indicators of muscle tone and can help differentiate between sleep stages, particularly in assessing for REM sleep. The chin muscle, in particular, is useful in determining the level of atonia expected during REM sleep, providing valuable information for sleep disorders diagnosis, such as narcolepsy.

Monitoring chin and submentalis muscle activity allows clinicians to observe the physiological changes that occur during sleep and determine whether a participant is falling asleep or entering different sleep stages. This can be essential for understanding the underlying mechanisms of sleep disorders and for elucidating the presence of excessive daytime sleepiness.

In contrast, while deltoids, forearm and finger flexors, and abdominal muscles may be monitored in other settings, they are not standard choices for EMG monitoring during the MSLT. Each of these muscle groups does not provide the same specific insights into the sleep-wake cycle that the chin and submentalis muscles do.