Elsevier

Sleep Medicine

Volume 14, Issue 11, November 2013, Pages 1071-1075
Sleep Medicine

Original Article
Polysomnographic abnormalities in patients with vascular cognitive impairment-no dementia

https://doi.org/10.1016/j.sleep.2013.07.003Get rights and content

Abstract

Objectives

We aimed to investigate subjective sleep quality and polysomnographic sleep structure features in patients with vascular cognitive impairment-no dementia (VCIND).

Methods

Fifty-six patients with VCIND, 48 patients with simple stroke (without cognitive impairment), and 48 control subjects were included. The Pittsburgh Sleep Quality Index (PSQI) and polysomnography (PSG) were used to analyze their sleep characteristics. The Montreal Cognitive Assessment (MoCA) was conducted to assess mental state.

Results

Patients with VCIND had higher PSQI scores compared with control subjects and simple stroke patients (P < .01). PSG revealed that patients with VCIND or stroke were more likely to experience prolonged sleep latency (SL), decreased sleep efficiency (SE), increased arousal, and reduced deep sleep and rapid eye movement (REM) sleep than controls. Patients with VCIND had significantly longer SL, increased periodic leg movements in sleep (PLMS), decreased SE, and increased arousal and sleep fragmentation compared to patients with simple stroke (P < .05). In VCIND patients, a significant positive correlation was found between SE and MoCA scores (r = 0.632; P < .001), though PSQI, SL, and arousal index were significantly negatively associated with MoCA scores (r = −0.787, −0.740, −0.772, respectively; P < .001 for all).

Conclusions

VCIND patients had different abnormal sleep features, including decreased SE, increased PLMS, and prolonged SL and sleep fragmentation. Abnormal sleep in VCIND may be associated with cognitive impairment.

Introduction

Vascular cognitive impairment (VCI) that does not meet dementia criteria is called VCI-no dementia (VCIND) and is characterized by early or mild cognitive impairment (MCI) due to cerebrovascular injuries with an insidious nature [1]. VCIND has been reported to occur in 26.9% of patients approximately 3 months after stroke onset [2]. Early diagnosis and appropriate interventions may help to improve the prognosis in VCIND. If there is no early detection or correct treatment, VCIND may most likely progress to dementia [3]. Studies have found that cognitive impairment often is accompanied by disrupted sleep which, in turn, is believed to exacerbate cognitive deficits [4], [5]; however, information on sleep disruption in VCIND remains limited. For these reasons, the aim of our study was to investigate the level of cognitive impairment and the clinical and polysomnographic characteristics of sleep disturbance in patients with VCIND.

Section snippets

Patients with VCIND

All VCIND patients were admitted in the Department of Neurology of the First Affiliated Hospital of the PLA General Hospital from January 2006 to June 2010. The following criteria described by Rockwood et al. [6] were used for VCIND diagnosis and patient inclusion: (1) presence of cerebrovascular disease, confirmed by cerebral magnetic resonance imaging (MRI); (2) evidence of cognitive impairment by neuropsychologic assessment; (3) cognitive impairment occurring within 3 months after stroke

Results

The patients in the VCIND group showed a higher frequency of restless legs syndrome (RLS) than those in the simple stroke group and the control group (16.1% vs 4.2% vs 2.1%, respectively; P = .016). The prevalence of obstructive sleep apnea syndrome was 35.7% and 31.3% in the VCIND and the stroke group, respectively, both of which were higher than the control group (12.5%) (P < .05). Rapid eye movement (REM) sleep behavior disorder was found in 8.9% of patients in the VCIND group, but there was no

Discussion

VCI is a syndrome caused by cerebrovascular risk factors or significant or nonsignificant cerebrovascular diseases. VCI includes VCIND; vascular dementia; and mixed dementia, which is believed to be a reflection of a disease process that evolves from mild to severe cognitive impairment [3]. VCIND has become the focus of intensive research because of its potential reversibility.

Cognitive function tests play an important role in the early detection of VCI. The Mini-Mental State Examination (MMSE)

Financial disclosures

None of the authors has financial interests that represent potential conflicts of interest.

Conflict of interest

The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2013.07.003.

. ICMJE Form for Disclosure of Potential Conflicts of Interest form.

Acknowledgment

Our study was partially supported by the Italian Ministry of Health (“Ricerca Corrente”).

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