A grounded theory study on the influence of sleep on Parkinson's symptoms.
BACKGROUND
Upon awaking, many Parkinson's patients experience an improved mobility, a phenomenon known as 'sleep benefit'. Despite the potential clinical relevance, no objective correlates of sleep benefit exist. The discrepancy between the patients' subjective experience of improvement in absence of objective changes is striking, and raises questions about the nature of sleep benefit. We aimed to clarify what patients reporting subjective sleep benefit, actually experience when waking up. Furthermore, we searched for factors associated with subjective sleep benefit.


METHODS
Using a standardized topic list, we interviewed 14 Parkinson patients with unambiguous subjective sleep benefit, selected from a larger questionnaire-based cohort. A grounded theory approach was used to analyse the data.


RESULTS
A subset of the participants described a temporary decrease in their Parkinson motor symptoms after sleep. Others did experience beneficial effects which were, however, non-specific for Parkinson's disease (e.g. feeling 'rested'). The last group misinterpreted the selection questionnaire and did not meet the definition of sleep benefit for various reasons. There were no general sleep-related factors that influenced the presence of sleep benefit. Factors mentioned to influence functioning at awakening were mostly stress related.


CONCLUSIONS
The group of participants convincingly reporting sleep benefit in the selection questionnaire appeared to be very heterogeneous, with only a portion of them describing sleep benefit on motor symptoms. The group of participants actually experiencing motor sleep benefit may be much smaller than reported in the literature so far. Future studies should employ careful inclusion criteria, which could be based on our reported data.
Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.|Sleep Medicine Centre Kempenhaeghe, Heeze, The Netherlands.|Eindhoven University of Technology, Eindhoven, The Netherlands.
Merel M
MM
van Gilst
Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
Iris C
IC
Cramer
Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
Bastiaan R
BR
Bloem
Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands. OvereemS@kempenhaeghe.nl.|Sleep Medicine Centre Kempenhaeghe, Heeze, The Netherlands. OvereemS@kempenhaeghe.nl.|Eindhoven University of Technology, Eindhoven, The Netherlands. OvereemS@kempenhaeghe.nl.
Sebastiaan
S
Overeem
Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.|Radboud Institute for Health Sciences, Scientific Institute for Quality of Healthcare, Radboud University Medical Center, Nijmegen, The Netherlands.
Marjan J
MJ
Faber
D000368:Aged; D005260:Female; D066296:Grounded Theory; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires; D014851:Wakefulness / Q000502:physiology
Grounded theory; Motor symptoms; Parkinson’s disease; Sleep; Sleep benefit