Algorithm uses wearable device to track narcolepsy naps

A wearable device using an algorithm may offer an objective way to track daytime napping and excessive daytime sleepiness (EDS) in people with type 1 narcolepsy (NT1), a study found.

The “highly sensitive and specific algorithm” detected substantially more frequent and longer daytime sleep in people with NT1 than in healthy participants and captured reductions in napping among those receiving Orzeyful (oveporexton), the researchers said.

The study, “An actigraphy-based algorithm to assess daytime napping in people with narcolepsy type 1,” was published in Sleep. Most study authors were employees of Takeda, the company that markets Orzeyful.

Narcolepsy is a neurological disorder that affects the brain’s ability to regulate sleep-wake cycles. Narcolepsy symptoms such as EDS can interfere with daily activities. Nearly 90% of people with narcolepsy regularly take daytime naps to help reduce sleepiness.

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Measuring naps

While actigraphy, a test that uses a small, watch-like device to continuously track movement and sleep-wake patterns, may help monitor sleepiness in real-world settings, existing algorithms may not reliably identify daytime naps.

Researchers in the U.S. addressed this gap by developing an actigraphy-based algorithm to estimate daytime napping. They used data from 2,151 participants in the Multi-Ethnic Study of Atherosclerosis, a dataset of older adults with subclinical cardiovascular disease (meaning they had no noticeable symptoms).

The researchers optimized and evaluated the method using data from studies enrolling people with NT1 and healthy controls. This included 32 participants from an observational study (NCT04445129) and 72 people with narcolepsy enrolled in a Phase 2 trial (NCT04096560) of TAK-994. The scientists subsequently applied the algorithm to 112 participants in a Phase 2 study (NCT05687903) evaluating Orzeyful against a placebo.

To assess whether the algorithm could provide clinically meaningful information about EDS, the investigators looked at three measures: the number of naps per day, days without naps, and total daytime sleep duration.

In MESA study participants, daytime naps varied according to participants’ level of sleepiness, which ranged from low-normal sleepiness to EDS. Over 28 days, participants had a median of 12 to 16 days without naps, while on the days they napped, they slept for about 28 to 50 minutes. Although the associations between daytime sleepiness and napping were modest, they were statistically significant

In the observational study, people with NT1 had an average of 4.4 days without napping over four weeks, compared with 17.2 days in healthy participants. Patients also slept an additional 33.5 minutes during the day and took about one more nap per day.

The algorithm identified periods of very little to no movement better than self-reported naps. “These findings may suggest that although actigraphy naps reliably capture periods of stillness, self-reported naps may be either falsely or imprecisely recalled,” the researchers wrote.

In the Phase 2  trial of TAK-994, participants had 7.3 to 8.6 more nap-free days over four weeks while receiving the treatment. On days when they napped, they spent 18 to 33 fewer minutes sleeping during the day and took 0.4 to 0.6 fewer naps.

In the Phase 2 study of Orzeyful, the researchers found similar improvements. Compared with the start of the study, participants who received Orzeyful had 6.1 to 11.9 more nap-free days over 28 days. They also took 0.4 to 0.9 fewer naps and spent 12 to 33 fewer minutes sleeping during the day.

These “initial results showed promise for the ability of orexin receptor 2–selective agonists such as [Orzeyful] to enable [people with narcolepsy] to approach healthy levels of limited daytime sleep,” the researchers wrote.