The utility of polysomnography for the diagnosis of NREM parasomnias: an observational study over 4 years of clinical practice.

Chiara Fois,Mary-Anne S Wright,Sofia H Eriksson,Matthew C Walker,Gianpietro Sechi

doi:10.1007/s00415-014-7578-2

Abstract

Polysomnography (PSG) is considered the gold standard for diagnosis of non-rapid eye movement (NREM) parasomnias, however its diagnostic yield has been rarely reported. We aimed to assess the diagnostic value of polysomnography in different categories of patients with suspected NREM parasomnia and define variables that can affect the outcome. 124 adults referred for polysomnography for suspected NREM parasomnia were retrospectively identified and divided into clinical categories based on their history. Each polysomnography was analysed for features of NREM parasomnia or different sleep disorders and for presence of potential precipitants. The impact on the outcome of number of recording nights and concomitant consumption of benzodiazepines and antidepressants was assessed. Overall, PSG confirmed NREM parasomnias in 60.5 % patients and showed a different sleep disorder in another 16 %. Precipitants were found in 21 % of the 124 patients. However, PSG showed limited value when the NREM parasomnia was clinically uncomplicated, since it rarely revealed a different diagnosis or unsuspected precipitants (5 % respectively), but became essential for people with unusual features in the history where different or overlapping diagnoses (18 %) or unsuspected precipitants (24 %) were commonly identified. Taking benzodiazepines or antidepressants during the PSG reduced the diagnostic yield. PSG has a high diagnostic yield in patients with suspected NREM parasomnia, and can reveal a different diagnosis or precipitants in over 40 % of people with complicated or atypical presentation or those with a history of epilepsy. We suggest that PSG should be performed for one night in the first instance, with leg electrodes and respiratory measurements and after benzodiazepine and antidepressant withdrawal.

Highlights

Parasomnias are undesirable physical events or experiences that occur during sleep [1] and are classified by the sleep stage from which they arise [1, 2]
We aimed to assess the diagnostic value of polysomnography in different categories of patients with suspected non-rapid eye movement (NREM) parasomnia and define variables that can affect the outcome. 124 adults referred for polysomnography for suspected NREM parasomnia were retrospectively identified and divided into clinical categories based on their history
We aimed to define the diagnostic value of PSG among different clinical categories of patients referred for PSG to a single Sleep Centre for suspected NREM parasomnia, in order to assess how often PSG is able to facilitate the diagnosis, either confirming NREM parasomnia or ruling out alternative diagnoses or precipitant factors

Summary

Introduction

Parasomnias are undesirable physical events or experiences that occur during sleep [1] and are classified by the sleep stage from which they arise [1, 2]. NREM parasomnias arise from non-rapid eye movement (NREM) sleep, typically from slow-wave sleep (SWS), and include three typical behaviours–confusional arousals, sleep walking and sleep terrors They are termed ‘‘arousal disorders’’ since the episodes usually occur during the transition from SWS to an arousal phase or awakening [1,2,3]. NREM parasomnia typically occurs in childhood an onset or persistence into adult life is not uncommon [1, 2, 4,5,6,7]. Their diagnosis is essentially clinical and often based on patient and bed-partner interviews. ICSD-2, and recently ICSD-3, propose essential diagnostic criteria for each of the three subtypes above [1, 2]

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