How do you confirm that a patient suspected of having narcolepsy is actually suffering from this rare neurological disorder?
The answer isn’t so straightforward, but most sleep clinicians and practitioners agree that patients with disorders of excessive daytime sleepiness may be checked for narcolepsy through a multiple sleep latency test (MSLT).
But even before performing a MSLT, it’s critical that the clinician distinguishes what may truly be causing the excessive daytime sleepiness. Could the patient simply be suffering from lifestyle-related insufficient nighttime sleep?
According to a wrist actigraphy paper published in Chest in 2011, it’s crucial that clinicians document a patient’s sleep habits for a period of time prior to performing a MSLT. Wrist actigraphy—which employs device that resembles a wristwatch and detects movement—is a useful tool for objectively documenting sleep habits.
“Actigraphy is different from data collected in sleep labs [in the form of sleep logs] and should not be viewed as a replacement for in-laboratory polysomnography when that is the clinically indicated test,” says Jennifer Martin, PhD, associate professor at the David Geffen School of Medicine at the University of California, Los Angeles in an e-mail interview with Sleep Review. “Actigraphy more accurately reflects sleep metrics when compared to patient-completed sleep logs or questionnaires.”
Yet reimbursement on actigraphy is not guaranteed, so its use has been limited.
That’s what led Robert Auger, MD, and several of his colleagues at the Center for Sleep Medicine at Mayo Clinic to conduct a study that compared data from sleep logs and actigraphy over a four-month period.
The study concluded that actigraphy does provide more reliable data than those from sleep logs and that the longitudinal total sleep time information from actigraphy did influence clinicians’ decisions to proceed with further testing for narcolepsy.
In a clinical update by Mayo Clinic, Auger further emphasizes the importance of using actigraphy prior to a MSLT. Auger was unable to be reached for this article. “We are performing the same tests as other doctors; the only thing we are doing differently is actigraphy,” he says on mayoclinic.org. “Adding that little piece makes all the difference. We have 20- and 30-year-olds diagnosed with narcolepsy; we put an actigraph on them and find out they are actually suffering from insufficient sleep. That can be a difficult conversation because it’s often not what they want to hear. Many are hard-driving executives who don’t want to be told they feel tired because they just need to sleep longer. Or they may have been consigned to a lifetime of stimulants and don’t want to give that up. Whatever the case, we have the actigraphy data to back up our conclusions and recommendations.”