title: Association of daytime sleepiness with nigrostriatal dopaminergic degeneration in early Parkinson's disease.
abstract: BACKGROUND
  Many patients with Parkinson's disease (PD) report daytime sleepiness. Its etiology, however, is still not fully understood. The aim of this study was to examine if the amount of nigrostriatal dopaminergic degeneration is associated with subjective daytime sleepiness in patients with PD.
  
  
  METHODS
  We investigated 21 patients with PD clinically and by means of [(123)I] FP-CIT-SPECT (DaTSCAN(R)). Each patient filled in the Epworth sleepiness scale (ESS), the Parkinson's Disease Sleep Scale (PDSS), and the self-rating depression scale according to Zung (SDS) to assess sleepiness, sleep quality, and depressive symptoms.
  
  
  RESULTS
  The mean specific dopamine transporter binding in the 21 PD patients (60.8 +/- 10.4 years, nine females, median Hoehn and Yahr stage 2.0) was decreased. Nine patients were in Hoehn and Yahr stage 1 (58.7 +/- 6.6 years, four females; ESS score 7.4 +/- 4.5; PDSS score 105.1 +/- 30.9), the other 12 patients were in Hoehn and Yahr stage 2 (62.4 +/- 12.6 years, five females; ESS score 6.7 +/- 4.7, PDSS score 97.1 +/- 25.6). Age, gender, ESS, and PDSS scores were not significantly different in both groups. However, ESS scores showed an inverse correlation with mean DAT binding in the striatum (r = -0.627, p = 0.03), the caudate nucleus (r = -0.708, p = 0.01), and the putamen (r = -0.599, p = 0.04) in patients with Hoehn and Yahr stage 2. There was no correlation of the ESS score with age, disease duration, UPDRS motor score, PDSS score, or depression score.
  
  
  CONCLUSIONS
  Subjective daytime sleepiness seems to be associated with dopaminergic nigrostriatal degeneration in early PD.
authors.affiliation: Department of Clinical Neurophysiology, University of Göttingen, Robert-Koch-Str 40, 37075, Göttingen, Germany. svenja.happe@klinikum-bremen-ost.de
authors.forename: Svenja
authors.initials: S
authors.lastname: Happe
authors.forename: Paul Christian
authors.initials: PC
authors.lastname: Baier
authors.forename: Kathrin
authors.initials: K
authors.lastname: Helmschmied
authors.forename: Johannes
authors.initials: J
authors.lastname: Meller
authors.forename: Klaus
authors.initials: K
authors.lastname: Tatsch
authors.forename: Walter
authors.initials: W
authors.lastname: Paulus
mesh_terms: D000368:Aged; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D006970:Disorders of Excessive Somnolence / Q000000981:diagnostic imaging / Q000209:etiology*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013378:Substantia Nigra / Q000000981:diagnostic imaging / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014326:Tropanes
chemical_list: D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; D004298:Dopamine