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

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.

Video polysomnographic findings in non‐rapid eye movement parasomnia

“…No differences were seen between subtypes of NREM parasomnia ( p = 0.271). Fifty‐one (9.9%) of the patients were receiving medications that could affect the diagnostic yield of the vPSG, including 31/512 (6%) on serotonin reuptake inhibitors, two (0.3%) on serotonin–norepinephrine reuptake inhibitors, 13 (2.5%) on tricyclic antidepressants, three (0.5%) on benzodiazepines and two (0.3%) on zaleplon (Fois et al, ). No correlation was found between the administration of the drugs above and the occurrence of NREM‐a, NREM‐A, or RWA and RBD, on the vPSG ( p > 0.05).…”

“…Sleep‐disrupting pathology, such as OSA and PLMS, has been reported in NREM parasomnia patients and is considered a potential precipitant for parasomnia behaviours, causing arousals and sleep fragmentation (Espa et al, ; Fois et al, ; Guilleminault et al, ; Kothare & Kaleyias, ; Ohayon et al, ). Prior sleep laboratory‐based studies have suggested that sleep studies may identify OSA and/or PLMS in a high proportion of patients.…”

“…Prior sleep laboratory‐based studies have suggested that sleep studies may identify OSA and/or PLMS in a high proportion of patients. For example, in a cohort of 124 patients with NREM parasomnia, 21% had sleep‐disrupting pathology seen on vPSG (Fois et al, ), and a study of 50 sleepwalkers undergoing polysomnography found an AHI >5 events/hr in 24% (Guilleminault et al, ). At a population level, a diagnosis of OSA appears to confirm a nearly four‐fold increase in the likelihood of frequent sleepwalking (Ohayon et al, ).…”

“…Our finding within a very large parasomnia cohort (that 28.9% of our patients had OSA and/or PLMS) is strikingly consistent with prior reports, and suggests that formal sleep studies should be considered, particularly in older, male, obese or sleepy patients presenting with an apparent NREM parasomnia. This is particularly the case in patients with sexsomnia, confusional arousals and POD, amongst whom there was a prevalence of physical pathology of almost 40% or above (Fois et al, ), and in older more obese patients with subjective daytime sleepiness. However, a direct association between concomitant sleep pathologies and NREM parasomnia‐related arousals was not confirmed in our study, with parasomnia behaviours being directly preceded by sleep‐disrupting pathology in only a minority of cases.…”

“…The diagnosis of NREM parasomnia is often made on the basis of clinical history, although video‐polysomnographic (vPSG) recordings may be required in assessing complicated or difficult cases, particularly when a diagnosis of epilepsy is suspected. (Bisulli et al, ; Derry et al, ; Fois, Wright, Sechi, Walker, & Eriksson, ; Zucconi et al, ). They may also reveal features suggestive of NREM parasomnia, such as abrupt arousals from NREM3 sleep, or may confirm the diagnosis by capturing relevant behaviours arising from NREM3 (Aldrich & Jahnke, ; Blatt, Peled, Gadoth, & Lavie, ; Fois et al, ; Kavey, Whyte, Resor, Jr, & Gidro‐Frank, ).…”