Although video polysomnography (vPSG) is not routinely recommended for the evaluation of typical cases of non‐rapid eye movement (NREM) parasomnias, it can aid diagnosis of unusual cases, other sleep disorders and complicated cases with REM behaviour disorder (RBD), and in differentiating parasomnias from epilepsy. In this study, we aimed to assess vPSG findings in consecutive patients with a clinical diagnosis of NREM‐parasomnia covering the whole phenotypic spectrum. Five hundred and twelve patients with a final diagnosis of NREM parasomnia who had undergone vPSG were retrospectively identified. vPSGs were analysed for features of NREM parasomnia and for the presence of other sleep disorders. Two hundred and six (40.0%) patients were clinically diagnosed with sleepwalking, 72 (14.1%) with sleep terrors, 39 (7.6%) with confusional arousals, 15 (2.9%) with sexsomnia, seven (1.4%) with sleep‐related eating disorder, 122 (23.8%) with mixed phenotype, and 51 (10.0%) with parasomnia overlap disorder (POD). The vPSG supported the diagnosis of NREM parasomnia in 64.4% of the patients and of POD in 98%. In 28.9% of the patients, obstructive sleep apnea (OSA) or/and periodic limb movements during sleep (PLMS) were identified, most commonly in older, male, sleepy and obese patients. vPSG has a high diagnostic yield in patients with NREM parasomnia and should be routinely performed when there is diagnostic doubt, or in patients where there is a suspicion of OSA and PLMS.

Background: Isolated REM sleep behavior disorder (iRBD) is known to be an early feature in some people with PD. Early motor anomalies may also be prodromes of PD. Standardized protocols, including quantitative motor tools for their measurement, are yet to be determined. Methods: A set of quantitative motor tests was used to compare iRBD patients with controls. These included two online keyboard-based tests, the BRadykineisa Akinesia INcoordination (BRAIN) test and the Distal Finger Tapping (DFT) test, a timed handwriting task and two separate motor assessments (10-meter walking and finger tapping) carried out both alone and during a mental (dual) task. This battery was compared with the motor section of the MDS-MDS-UPDRS-III. ROC analyses were used to measure diagnostic accuracy. Results: We included 33 patients with video-PSG-confirmed iRBD (68.88 years; SD 8.07) and 29 age and sex matched controls. The iRBD group performed the alternate tapping task (BRAIN test) and single finger tapping task (DFT test) more slowly (p<0.001 and p=0.020 respectively) and erratically (p<0.001 and p=0.009 respectively) than controls. Handwriting speed was on average 10 seconds slower in the iRBD compared with controls (p=0.004). Unlike controls, dual tasking unmasked motor deficits in the iRBD group with patients having a slower walking pace (p<0.001) and smaller amplitude (p=0.001) with slower finger tapping and (p=0.007) than when the task was done in isolation. The combination of BRAIN & DFT tests with the effect of dual tasking on walking and finger tapping performance gave the overall accuracy of 90.3% sensitivity for 89.3% specificity (AUC 0.94 (95% CI 0.88 to 0.99)), which was substantially higher than the accuracy of the MDS-UPDRS-III (minus action tremor) (69.7% sensitivity for 72.4% specificity and AUC 0.81, 95% CI 0.71 to 0.91) for detecting motor abnormalities. Conclusion: The tests used in this study were able to detect early patterns of motor dysfunction that are not included in standardized clinical scales. Keyboard tapping was found to be slow and erratic in people with iRBD. Dual tasks unmasked hypokinetic finger tapping and slower walking pace. This study suggests that speed, incoordination, and dual task motor deterioration might be potential indicators of incipient PD in iRBD.