Main studies considered in our review about the presence of obstructive, restrictive and central respiratory dysfunction in Parkinson's disease patients

First author [ref] (year)Number of patientsClinical scoreDisease durationPharmacological washoutObstructive defectRestrictive defectCentral ventilatory dysfunction
Vincken [7] (1984)27H&Y 4 (mean in the obstructive patients)Not availableNot reported10 (upper airway)Not foundNot assessed
Izquierdo-Alonso [8] (1994)63H&Y 2.55 (mean), UPDRS 30 (mean)5 years (mean)No13 (upper airway)54Not assessed
Sabatè [9] (1996)58UPDRS III, mean not availableNot available8 h36 (upper airway) versus 21 (lower airway)16Not assessed
Onodera [10] (2000)25H&Y 2–3Not availableNoNot assessedNot assessedImpairment response to hypoxia versus control group
Herer [11] (2001)21H&Y 2.6 (mean)0.25–11 years12 h5 (upper airways obstruction)Not foundNot assessed
De Pandis [12] (2002)12H&Y 4.08 (mean)8–25 years12 hNot foundMore severe pattern in off stageNot assessed
Weiner [13] (2002)20H&Y 2–3, UPDRS III 41.4 (mean in off)Not availableNot reportedNot foundMild restrictive patternNot assessed
Sathyaprabha [14] (2005)35H&Y 1–21–5 years12 h233Not assessed
Seccombe [15] (2011)19H&Y 2.5 (mean)2–23 yearsNo12Impairment response to hypercapnia versus control group
Baille [16] (2018)41UPDRS III 19 (mean)0.20–3.6 years12 h61Not assessed

H&Y: Hoehn & Yahr; UPDRS: Unified Parkinson's Disease Rating Scale.