DIFFERENTIAL-DIAGNOSIS OF RESPIRATORY DYSKINESIA - A PREVALENCE STUDYUSING COMPUTER-ANALYSIS OF SPIROGRAPH DATA

A survey of respiratory dyskinesia for 248 inpatients receiving neurol eptic drugs was undertaken to explore the prevalence and subtype of re spiratory dyskinesia using computer analysis of spirograph data monito red by both a Somniprobe nasal thermistor and a strain-gauge. By clini cal examination, 23 patients showing irregular respiratory rate, tachy pnea, or grunting were suspected to have respiratory dyskinesia. These 23 patients were then examined by nasal thermister for air flow, and strain gauge for thoracic movement. The coefficient of variation (CV) in distance from bottom to bottom of respiratory movements over 3 min was measured for each patient. For seven patients, their CVs were +2 S D greater than the mean CV found among 10 normal controls. The number of bursts of air flow (thermistor) was subtracted from the number of r espiratory movements (strain gauge) as an estimate of desynchronizatio n or obstruction. For three patients, this difference was +2 SD greate r than the mean difference found among 10 normal controls. All three o f these 'desynchronized' or 'obstructive' patients were among the seve n who met 'irregularity' criteria as above. The prevalence of respirat ory dyskinesia was 2.8 per cent (seven out of 248 subjects surveyed) a nd 13 per cent among those with TD populations. Respiratory dyskinesia was classified into two subtypes: the obstructive type with irregular respiratory movement and the irregular respiratory type. A computer a nalysis of spirograph data will be useful for the investigation of res piratory dyskinesia. (C) 1997 by John Wiley & Sons, Ltd.