Utility of actigraphy in the diagnosis of obstructive sleep apnea.

STUDY OBJECTIVES

To determine whether adding actimetry to simplified polygraphy (respiratory-parameter monitoring without neurophysiologic variable recording) improves apnea-hypopnea index (AHI) evaluation as compared to simplified polygraphy alone.

DESIGN

Comparison of AHI values obtained by all-night polysomnography and by simplified polygraphy with and without actimetry.

SETTING

A teaching-hospital sleep laboratory in Garches, France.

PATIENTS

20 adults with suspected obstructive sleep apnea syndrome (OSAS).

MEASUREMENTS AND RESULTS

Data were analyzed by two scorers working independently. AHI was calculated as the number of apneas and hypopneas per hour of sleep time (polysomnography: AHI-pg), per hour of time in bed (simplified polygraphy: AHI-tib), and per hour of actimetry-estimated total sleep time (AHI-act). AHI-pg showed that 12 patients had OSAS (AHI>10), which was severe (AHI > or =30) in eight. AHI-act was more closely correlated to AHI-pg (r=0.976) than was AHI-tib (r=0.940). According to the Bland and Altman method, AHI-tib underestimated the AHI in two patients and AHI-act overestimated the AHI in one patient. For the diagnosis of severe OSAS, sensitivity and negative predictive value were 50% and 75% with AHI-tib as compared to 88% and 92.5% with AHI-act.

CONCLUSIONS

Actimetry, when added to simplified polygraphy, may assist in the diagnosis of OSAS.