REM Latency May Predict Poor Recovery After Stroke

BALTIMORE—Increased REM latency may be associated with an increased likelihood of poor short- and long-term recovery of neurologic function after stroke, according to research presented at the 27th Annual Meeting of the Associated Professional Sleep Societies. In comparison, individuals with normal REM latency and a normal proportion of REM sleep may have a reduced risk of poor recovery.

Preliminary findings from an ongoing study indicate that patients with reduced REM sleep also tend to have a high risk for poor short-term and long-term recovery after stroke, reported Stephany Fulda, PhD, postdoctoral researcher at the Sleep and Epilepsy Center at the Civic Hospital of Lugano, Switzerland. Reduced REM sleep was not as strongly associated with this outcome as increased REM latency was, however.

An Ongoing Study of Sleep and Stroke Recovery
Dr. Fulda, Claudio Bassetti, MD, Professor of Neurology at the University Hospital of Zurich, and colleagues are conducting a prospective, multicenter cohort study to determine whether sleep during the acute phase after stroke can predict the recovery of neurologic function. The researchers are selecting patients with stroke between ages 35 and 75 who are admitted to the hospital within two days after stroke onset. Participants undergo polysomnography within one week after hospital admission.

In a substudy, Dr. Fulda selected patients who had an NIH Stroke Scale (NIHSS) score higher than zero and a valid NIHSS score at discharge. The investigators examined 65 patients for an analysis of short-term recovery, which was defined as recovery at discharge, and 50 patients for an analysis of long-term recovery, which was defined as recovery at three months after discharge. Recovery was rated as good, poor, or very poor based on the deviation from the population’s expected improvement, given the severity of the stroke at admission.

Most Patients Had Good Recovery After Stroke
A total of 49 patients had good short-term recovery, eight patients had poor short-term recovery, and eight patients had very poor short-term recovery. The researchers found no differences in age, gender, or BMI between patients with good and poor short-term recovery. Sleep-related breathing disorders were not correlated with poor recovery, but decreased percentage of REM sleep and increased REM latency were correlated with a poor outcome.

Twelve patients had poor long-term recovery, and the rest had good long-term recovery. Demographic variables did not differ significantly between patients with good and poor long-term recovery, but REM latency and decreased REM sleep correlated with poor recovery. A logistic regression analysis indicated that increased REM latency was strongly associated with poor recovery.

REM latency is influenced by several variables, including factors that affect pre-REM or non-REM sleep or wakefulness. “REM latency could be a sensitive measure that picks up different kinds of disturbances, including sleep-related breathing disorders,” without being causally implicated in poor recovery, said Dr. Fulda. Whether reduced REM sleep is a causal risk factor for poor recovery after stroke is unclear, she said. Research has not yet established whether the maintenance of REM sleep is a protective factor, she concluded.

—Erik Greb
Senior Associate Editor

BALTIMORE—Increased REM latency may be associated with an increased likelihood of poor short- and long-term recovery of neurologic function after stroke, according to research presented at the 27th Annual Meeting of the Associated Professional Sleep Societies. In comparison, individuals with normal REM latency and a normal proportion of REM sleep may have a reduced risk of poor recovery.

Preliminary findings from an ongoing study indicate that patients with reduced REM sleep also tend to have a high risk for poor short-term and long-term recovery after stroke, reported Stephany Fulda, PhD, postdoctoral researcher at the Sleep and Epilepsy Center at the Civic Hospital of Lugano, Switzerland. Reduced REM sleep was not as strongly associated with this outcome as increased REM latency was, however.

An Ongoing Study of Sleep and Stroke Recovery
Dr. Fulda, Claudio Bassetti, MD, Professor of Neurology at the University Hospital of Zurich, and colleagues are conducting a prospective, multicenter cohort study to determine whether sleep during the acute phase after stroke can predict the recovery of neurologic function. The researchers are selecting patients with stroke between ages 35 and 75 who are admitted to the hospital within two days after stroke onset. Participants undergo polysomnography within one week after hospital admission.

In a substudy, Dr. Fulda selected patients who had an NIH Stroke Scale (NIHSS) score higher than zero and a valid NIHSS score at discharge. The investigators examined 65 patients for an analysis of short-term recovery, which was defined as recovery at discharge, and 50 patients for an analysis of long-term recovery, which was defined as recovery at three months after discharge. Recovery was rated as good, poor, or very poor based on the deviation from the population’s expected improvement, given the severity of the stroke at admission.

Most Patients Had Good Recovery After Stroke
A total of 49 patients had good short-term recovery, eight patients had poor short-term recovery, and eight patients had very poor short-term recovery. The researchers found no differences in age, gender, or BMI between patients with good and poor short-term recovery. Sleep-related breathing disorders were not correlated with poor recovery, but decreased percentage of REM sleep and increased REM latency were correlated with a poor outcome.

Twelve patients had poor long-term recovery, and the rest had good long-term recovery. Demographic variables did not differ significantly between patients with good and poor long-term recovery, but REM latency and decreased REM sleep correlated with poor recovery. A logistic regression analysis indicated that increased REM latency was strongly associated with poor recovery.

REM latency is influenced by several variables, including factors that affect pre-REM or non-REM sleep or wakefulness. “REM latency could be a sensitive measure that picks up different kinds of disturbances, including sleep-related breathing disorders,” without being causally implicated in poor recovery, said Dr. Fulda. Whether reduced REM sleep is a causal risk factor for poor recovery after stroke is unclear, she said. Research has not yet established whether the maintenance of REM sleep is a protective factor, she concluded.

—Erik Greb
Senior Associate Editor

BALTIMORE—Increased REM latency may be associated with an increased likelihood of poor short- and long-term recovery of neurologic function after stroke, according to research presented at the 27th Annual Meeting of the Associated Professional Sleep Societies. In comparison, individuals with normal REM latency and a normal proportion of REM sleep may have a reduced risk of poor recovery.

Preliminary findings from an ongoing study indicate that patients with reduced REM sleep also tend to have a high risk for poor short-term and long-term recovery after stroke, reported Stephany Fulda, PhD, postdoctoral researcher at the Sleep and Epilepsy Center at the Civic Hospital of Lugano, Switzerland. Reduced REM sleep was not as strongly associated with this outcome as increased REM latency was, however.

An Ongoing Study of Sleep and Stroke Recovery
Dr. Fulda, Claudio Bassetti, MD, Professor of Neurology at the University Hospital of Zurich, and colleagues are conducting a prospective, multicenter cohort study to determine whether sleep during the acute phase after stroke can predict the recovery of neurologic function. The researchers are selecting patients with stroke between ages 35 and 75 who are admitted to the hospital within two days after stroke onset. Participants undergo polysomnography within one week after hospital admission.

In a substudy, Dr. Fulda selected patients who had an NIH Stroke Scale (NIHSS) score higher than zero and a valid NIHSS score at discharge. The investigators examined 65 patients for an analysis of short-term recovery, which was defined as recovery at discharge, and 50 patients for an analysis of long-term recovery, which was defined as recovery at three months after discharge. Recovery was rated as good, poor, or very poor based on the deviation from the population’s expected improvement, given the severity of the stroke at admission.

Most Patients Had Good Recovery After Stroke
A total of 49 patients had good short-term recovery, eight patients had poor short-term recovery, and eight patients had very poor short-term recovery. The researchers found no differences in age, gender, or BMI between patients with good and poor short-term recovery. Sleep-related breathing disorders were not correlated with poor recovery, but decreased percentage of REM sleep and increased REM latency were correlated with a poor outcome.

Twelve patients had poor long-term recovery, and the rest had good long-term recovery. Demographic variables did not differ significantly between patients with good and poor long-term recovery, but REM latency and decreased REM sleep correlated with poor recovery. A logistic regression analysis indicated that increased REM latency was strongly associated with poor recovery.

REM latency is influenced by several variables, including factors that affect pre-REM or non-REM sleep or wakefulness. “REM latency could be a sensitive measure that picks up different kinds of disturbances, including sleep-related breathing disorders,” without being causally implicated in poor recovery, said Dr. Fulda. Whether reduced REM sleep is a causal risk factor for poor recovery after stroke is unclear, she said. Research has not yet established whether the maintenance of REM sleep is a protective factor, she concluded.

—Erik Greb
Senior Associate Editor