PD	Parkinson’s disease
iPD	idiopathic Parkinson’s disease
AD	Alzheimer’s disease
CNS	Central nervous system
REM	Rapid eye movement
NREM	Non-rapid eye movement
RBD	Rapid eye movement sleep behavior disorder
iRBD	idiopathic Rapid eye movement sleep behavior disorder
EDS	Excessive daytime sleeping
RLS	Restless leg syndrome
OSA	Obstructive sleep apnea
SRBD	Sleep-related breathing disorder
CRSWD	Circadian rhythm sleep–wake disorder
DSWPD	Delayed sleep–wake phase disorder
α-SYN	Alpha-synuclein
SCNA	Alpha-synuclein
PARK2	Parkin 2
LRRK2	Leucine-rich repeat kinase 2
PINK	PTEN-induced putative kinase
PRKN	Parkin RBR E3 ubiquitin-protein ligase
GBA	Glucocerebrosidase genes
ATP13A2	ATPase type 13A2
ICSD	International Classification of sleep disorders
CSF	Cerebrospinal fluid
LBD	Lewy body dementia
SNPc	Substantia nigra pars compacta
SN	Substantia nigra
VTA	Ventral tegmental area
PVN	Paraventricular nucleus
MPN	Medial preoptic nucleus
MPTP	1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
DA	Dopamine
GABA	Gamma-aminobutyric acid
IL-1β	Interleukin-1β
TNF-α	Tumour necrosis factor- α
ESS	Epworth sleepiness scale
DaTSCAN	Dopamine transporter scan
CLOCK	Circadian locomotor output cycles kaput
HCRT2-SAP	Hypocretin-2-sap
CPAP	Continuous positive airway pressure
EMG	Electromyographic
MoCA	Montreal cognitive assessments
MMSE	Mini-mental State Examination
D2R	Dopamine 2 receptor
PLMS	Periodic leg movements in sleeping
ALS	Amyotrophic lateral sclerosis
ARAS	Ascending reticular activating system
SCN	Suprachiasmatic nucleus
PER3	Period circadian regulator 3
CRY1	Cryptochrome
Nr1d1	Nuclear receptor subfamily 1 group D member 1
Nr1d2	Nuclear receptor subfamily 1 group D member 2
PDSS	Parkinson’s disease sleep scale
SCOPA	Scales for outcomes in PD sleep
PSQI	Pittsburgh sleep quality index
RBDSQ	RBD screening questionnaire
RBD-I	Innsbruck RBD inventory
RBDQ-HK	Hong Kong RBD questionnaire
RBD-IQ	RBD-single question screen
MSGBs	Minor salivary gland biopsies
CSHQ	Cleveland sleep habits questionnaire
MRPI	Magnetic resonance parkinsonism index
MRI	Magnetic resonance imaging
DTI	Diffusion tensor imaging
fMRI	Functional magnetic resonance imaging
FA	Fractional anisotropy
TMS	Transcranial magnetic stimulation
DAT-SPECT	Dopamine transporter single-photon emission computed tomography
BLT	Bright light therapy
CBT	Cognitive behavioral therapy
PBM	Photobiomodulation
tDCS	Transcranial direct current stimulation
LCIG	Levodopa/carbidopa intestinal gel
LCE	Levodopa/carbidopa/entacapone