Elevation of serum TNF-α levels in mild and moderate Alzheimer patients with daytime sleepiness.

OBJECTIVES

Sleep disturbance has been noted to accompany Alzheimer disease and is more pronounced as dementia severity increases. The aim of this study was to examine whether sleep disturbance in a cohort of patients with mild/moderate AD was associated with serum levels of IL-1β and TNF-α.

METHODS

Forty three drug-free AD patients and twenty two healthy controls were evaluated. All subjects underwent two consecutive full-night polysomnography. Their daytime sleepiness was assessed by Epworth Sleepiness Scale (ESS). Serum levels of IL-1β and TNF-α were measured by enzyme linked immunoassays.

RESULTS

AD patients showed lower sleep efficiency, more awakenings and less slow wave sleep (SWS). IL-1β was detectable only in two AD patients. Serum TNF-α concentrations did not differ significantly between AD patients and controls. When AD patients were classified as AD patients with daytime sleepiness (n=20, ESS>10) or AD patients without daytime sleepiness (n=23, ESS<10) according to their ESS scores, serum levels of TNF-α was significantly higher in AD patients with daytime sleepiness than that in those without daytime sleepiness or controls (32.7±17.9 vs 5.2±2.4, p<0.05; 40.9±22.3 vs 5.7±2.2, p<0.05). Serum level of TNF-α was significantly correlated with ESS score.

DISCUSSION

These data indicate that daytime sleepiness in mild and moderate AD patients is associated with elevation of serum TNF-α concentrations.