Table 3

CSF neuronal injury markers: tau, neurofilament light chain (NF-L) and glial fibrillary acidic protein (GFAP) in parkinsonian disorders

Research groups	Participants	Analyte	Method	Main findings
Kang et al21	PD n=39 (drug-naïve patients), HC n=63	t-tau, p-tau	Bead-based multi-analyte assay (Luminex)	Decrease in t-tau+p-tau in PD vs controls
Luk et al64	PDD n=11, PSP n=44, CBS n=22, AD n=11, controls n=34	3R/4R isoforms	Immuno-PCR (adapted from sandwich ELISAs)	Decrease in 4R-tau in PSP and AD vs controls Lower 4R-tau in AD vs PDD -No difference in 3R-tau
Hall et al 201226	PD n=90, PDD n=33, DLB n=70, PSP n=45, CBD n=12, MSA n=48, AD n=48, controls n=107	t-tau, p-tau NF-L	Bead-based multi-analyte assay (Luminex)	Increased t-and p-tau in AD vs DLB+PDD NF-L differentiates PD from atypical parkinsonism
Bech et al32	PD n=22, PDD n=3, DLB n=11, MSA n=10, PSP n=20, CBD n=3	NF-L	ELISA	Higher NF-L levels in atypical parkinsonian disorders vs PD No difference between parkinsonian groups
Andersson et al34	DLB n=47, PDD n=17, AD n=150	t-tau, p-tau	ELISA	Increased t-tau in DLB vs PDD
Shi et al22	Discovery cohort: PD n=126, MSA n=32, AD n=50, controls n=137 Validation cohort: PD n=83	t-tau, p-tau	Bead-based multi-analyte assay (Luminex)	-Decrease in PD vs to controls -Decrease in PD+MSA vs AD
Parnetti et al 201127	PD n=38, DLB n=32, AD n=48, FTD n=31, controls n=32	t-tau, p-tau	ELISA	Increase in AD>FTD>DLB vs PD and controls No difference between PD and controls
Kuiperij et al102	NA	33/55 kDa tau forms	Immunoprecipitation assay and western blotting	Not able to detect tau form ratio Suggested that 33/55 kDa bands seen are heavy and light IgG chains
Borroni et al103	PSP n=18, CBS n=16, FTD n=28, controls n=25	33/55 kDa tau forms	Immunoprecipitation assay and western blotting	tau form ratio significantly reduced in PSP vs other groups
Constantinescu et al71	PD n=10, MSA n=21, PSP n=14, CBD n=11, HC n=59 (×2 consecutive samples)	NF-L GFAP	ELISA	NF-L: normal levels in PD, elevated in MSA, PSP+CBD No statistical significance overtime GFAP: no difference
Montine et al28	PD n=41, PDD n=11, AD n=49, HC n=150	t-tau, p-tau	Bead-based multi-analyte assay (Luminex)	t-tau: no difference between parkinsonian groups p-tau: reduced in PD vs HC
Süssmuth et al29	PSP-RS n=20, PSP-P n=7, MSA-P n=11, MSA-C n=14, PD n=23, controls n=20	t-tau, p-tau GFAP	ELISA	p-tau/t-tau ratio lower in PSP and MSA vs PD GFAP: increase in parkinsonian syndromes (no difference between disease groups)
Alves et al23	PD n=109, AD n=20, HC n=36	t-tau, p-tau	ELISA	No difference between PD and controls
Ohrfelt et al30	PD n=15, DLB n=15, AD n=66, controls n=55	t-tau, p-tau	ELISA	No difference between parkinsonian groups
Compta et al24	PD n=20, PDD n=20, HC n=15	t-tau, p-tau	ELISA	t- and p- tau: increase in PDD vs PD and controls
Parnetti et al25	PD n=20, PDD n=8, DLB n=19, AD n=23, HC n=20	t-tau, p-tau	ELISA	t-tau: DLB > PDD > controls p-tau: no difference between parkinsonian groups
Borroni et al65	PSP n=21, CBS n=20, FTD n=44, AD n=15, PD n=10, DLB n=15, controls n=27	33/55 kDa tau forms	Semiquantitative immunoprecipitation and western blotting	tau forms significantly reduced in PSP vs controls and other neurodegenerative diseases
Brettschneider et al70	PD n=22, MSA n=21, PSP n=21, CBD n=6, controls n=45	NF-H	ELISA	Increased in MSA and PSP vs PD, CBD and controls

AD, Alzheimer's disease; CBD, corticobasal degeneration; CBS, corticobasal syndrome; CSF, cerebrospinal fluid; DLB, dementia with Lewy bodies; FTD, frontotemporal dementia; HC, healthy controls; MSA, multiple system atrophy; MSA-C, multiple system atrophy cerebellar type; MSA-P, multiple system atrophy parkinsonian type; NF_H, neurofilament heavy chain; NF-L, neurofilament light chain; PD, Parkinson's disease; PDD, Parkinson's disease dementia; PSP, progressive supranuclear palsy; PSP-P, progressive supranuclear palsy–parkinsonism; PSP-RS, progressive supranuclear palsy–Richardson's syndrome.