Somatosensory function is impaired in patients with idiopathic REM sleep behaviour disorder

• Published in: Sleep medicine Vol. 42; pp. 83 - 89
• Main Authors: Strobel, A.V., Tankisi, H., Finnerup, N.B., Fuglsang-Frederiksen, A., Jennum, P., Svendsen, K.B., Kirov, F.I., Otto, M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2018
• Subjects: Alpha-synucleinopathies; Laser evoked potentials; Parkinson's disease; Quantitative sensory testing; REM sleep behavior disorder; Somatosensory function; Parkinson's disease; Alpha-synucleinopathies; Laser evoked potentials; Somatosensory function; Quantitative sensory testing; REM sleep behavior disorder
• ISSN: 1389-9457; 1878-5506; 1878-5506
• DOI: 10.1016/j.sleep.2017.09.035

Idiopathic REM sleep behaviour disorder (iRBD) has been recognised as a significant biomarker for developing a neurodegenerative alpha-synucleinopathy, which is why iRBD is considered to be a prodromal state for alpha-synucleinopathies including Parkinson's disease (PD). Many patients with PD suffer from complaints of pain and present impaired somatosensory function. We hypothesized that pain perception and somatosensory function could be altered already in a preclinical stage of PD including iRBD. Hence, the objective of this study was to investigate pain perception and somatosensory function in patients with iRBD. Quantitative sensory testing (QST), laser evoked potentials (LEPs), and conditioned pain modulation (CPM) testing were performed in 13 iRBD patients without any clinical signs of PD or narcolepsy (11 males, 2 females, mean age 65.2 years) and 15 gender- and age-matched healthy control subjects (12 males, 3 females, mean age 65.8 years). Thermal detection thresholds were higher in the iRBD group compared with the control group (cold detection threshold (CDT) p = 0.020, thermal sensory limen (TSL) p = 0.001), indicating an impaired temperature sensation in iRBD patients. The N2/P2 LEPs amplitude was smaller in iRBD patients than controls, but not statistically significant (p = 0.053). This study found an impaired somatosensory function in iRBD patients, suggesting that somatosensory impairment might be an early feature in the neurodegenerative process of PD. •Thermal sensory impairment was found in patients with idiopathic RBD (iRBD).•iRBD patients showed a tendency to decreased amplitudes of laser evoked potentials.•Impaired sensory function may be used as a marker for later Parkinson's disease.