Sleep disturbances may influence vascular cognitive decline

Sep 23 2013

By Lucy Piper, Senior medwireNews Reporter

Patients with vascular cognitive impairment without dementia have distinct abnormal sleep patterns that may be related to their cognitive deficits, researchers report.

Their results showed that these patients had more severe sleep structure disruption and higher scores on the Pittsburgh Sleep Quality Index (PSQI) than patients with stroke and healthy individuals.

Moreover, they had significantly lower scores on the Montreal Cognitive Assessment, indicating greater cognitive impairment. And scores on this measure correlated positively with sleep efficiency and negatively with PSQI scores, sleep latency, and arousal index scores.

“This finding suggests that the level of cognitive impairment may be influenced by sleep structure disruption and that both may interact to ultimately contribute to severe consequences such as dementia,” say the researchers, led by Raffaele Ferri (Oasi Institute for Research on Mental Retardation and Brain Aging, Troina, Italy).

As reported in Sleep Medicine, the team assessed the sleep characteristics of 56 patients with vascular cognitive impairment, 48 with simple stroke without cognitive impairment, and 48 healthy control individuals.

The patients with vascular cognitive impairment had an average total PSQI score of 11.88, compared with 9.17 for those with stroke and 7.38 for controls.

Polysomnography showed that patients with vascular cognitive impairment or stroke were more likely to experience prolonged sleep latency, decreased sleep efficiency, increased arousal, and reduced deep sleep and rapid eye movement sleep than controls.

But the severity of sleep disturbance was significantly worse for patients with vascular cognitive impairment than for those with stroke. The former group’s sleep latency was, on average, 6.5 minutes longer and their sleep efficiency 3.7% poorer, while scores on the arousal index and the periodic limb movements during sleep index were 6.0 and 3.8 points higher, respectively.

“Our study showed that patients with VCIND [vascular cognitive impairment–no dementia] have significant night sleep structure disruption and that cognitive impairment was closely associated with some sleep structure abnormalities,” the researchers comment.

“Thus early identification of disordered sleep in these patients is important for their clinical management, and future studies will clarify if cognitive function deterioration might benefit from a careful management of sleep disorders in patients with VCIND.”

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