Table 2.

Other salivary biomarkers used in the neurodegenerative diseases (NDDs) diagnostics.

Reference	Study Population	Salivary Biomarker	Analytical Method	Endpoints
Lau et al. 2015	20 patients with AD, 20 with PD, and 20 healthy controls	Aβ42 t-tau p-tau trehalose	ELISA, EG-IDFET biosensor	↑ trehalose and ↑ p-tau vs controls Aβ42 not detected t-tau unchanged
Shi et al. 2011	21 patients with AD and 38 healthy controls	Aβ42 t-tau p-tau	ELISA (Luminex assay)	Aβ42 not detected ↑t-tau and ↑p-tau vs controls p < 0.05
Ashton et al. 2018	53 patients with AD and 160 healthy controls	t-tau	Single molecule array (SIMOA)	t-tau unchanged
Pekels et al. 2019	46 patients with AD and 47 healthy controls	t-tau p-tau	Western Blot	↑ p-tau, ↑t-tau at phosphorylation site S396, S404, S400, T403, T404 vs controls
Bakhtiari et al. 2017	15 patients with AD and 15 healthy controls	AChE activity	Ellman’s colorimetric method	AChE activity unchanged
Boston et al. 2008	15 patients with AD and 13 healthy controls	AChE activity	Ellman’s colorimetric method	AChE activity unchanged
Sayer et al. 2004	22 AD responders to AChE inhibitor, 14 AD no responders to AChE inhibitor, 11 healthy controls	AChE activity	Ellman’s colorimetric method	↓ AChE activity in the saliva of AD no responders vs controls (p < 0.005) AChE activity in the saliva of AD responders and AD no responders did not statistically different
Carro et al. 2017	80 patients with AD and 91 healthy controls	lactoferrin	ELISA	↓ lactoferrin in the saliva of AD patients vs healthy controls (p < 0.001)
Liang et al. 2015	256 patients with AD and 218 healthy controls	sphinganine-1-phosphate ornithine phenyllactic acid inosine 3-dehydrocarnitine hypoxantine	UPLC-MS	↑ sphinganine-1-phosphate,↑ ornithine, ↑ phenyllactic acid ↓ inosine, ↓3-dehydrocarnitine ↓ hypoxantine in the saliva of AD vs controls (p < 0.01)