Ambulatory polysomnography using a new programmable amplifier system with on-line digitization of data: technical and clinical findings.
A new system for polysomnographic recording at home is presented. It consists of a 12 to 24-channel amplifier system with direct digitization of the polygraph signals using a portable computer. Sampling frequency, amplification and filter settings can be defined by the user, and the signals are evaluated at bedside. Technical testing proved a high signal/noise ratio, linear amplification and a good signal quality. Clinical testing of the first 100 recordings showed that they were acceptable for conventional sleep scoring in 98 cases. A comparison of two consecutive recordings was done in 9 healthy subjects and 11 patients with rheumatic disorders. Using conventional sleep staging, only a slight "first night effect" (FNE) was demonstrated in the sleep architecture. Power spectral analysis using autoregressive modeling demonstrated only a difference of power between the 2 nights in the beta (14.5-25 Hz) band. In conclusion, the usability and technical advantages make the system very suitable for ambulatory recordings and only a minimal FNE should be considered when results are evaluated.
Drewes
A M
AM
Department of Rheumatology, Aalborg Hospital, Denmark.
Nielsen
K D
KD
Taagholt
S J
SJ
Svendsen
L
L
Bjerregård
K
K
Nielsson
L
L
Kristensen
L
L
D000328:Adult; D000368:Aged; D000669:Amplifiers, Electronic; D001172:Arthritis, Rheumatoid; D004867:Equipment Design; D005260:Female; D005356:Fibromyalgia; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012895:Sleep, REM; D018709:Statistics, Nonparametric