Meta-Analysis of Visual Evoked Potential and Parkinson’s Disease

Table 1

Characteristics and quality of studies included in the meta-analysis.

Author(s) year	Country	Diagnostic criteria	Mean duration (months)	Motor and cognitive function	Number of eyes		Mean age (years)		Sex (men/women)		Newcastle-Ottawa Scale (NOS)
					PD	HC	PD	HC	PD	HC	Selection	Comparability	Exposure	Total score
Altintaş 2008 [15]	Turkey	UKBB	54.96	UPDRS	34	22	59.29	58.09	9/8	6/5	3	1	3	7
Antal 2000 [16]	Austria	NR	58.1	UPDRS, H&Y, ADL, MMSE	40	40	65.3	59.8	13/7	13/7	2	2	3	7
Bodis-Wollner 1978 [2]	USA	NR	97.8	NR	70	52	62	60	NR	NR	2	1	2	5
Buttner 1996 [18]	Germany	NR	64.8	UPDRS, H&Y	78	86	64.0	62.8	20/19	18/25	2	1	3	6
Cubo 2014 [19]	Spain	UKBB	98.4	SPES/SCOPA, H&Y, MMSE	60	60	65.4	62.9	18/12	15/15	3	1	3	7
Daniels 1994 [9]	UK	NR	NR	NR	32	40	64.36	66.95	NR	NR	2	1	3	6
Deng 2006 [25]	China	CMA	NR	NR	64	60	64	64	20/12	19/11	2	1	2	5
Ehle 1982 [8]	USA	NR	65	H&Y	50	36	64	56	NR	NR	2	1	3	6
Garcia-Martin, Elena 2014 [20]	Spain	UKBB	92.4	H&Y, SE-ADL	46	33	70.72	69.67	29/17	21/12	3	2	3	8
Gawel 1981 [7]	England	NR	NR	NR	94	52	67	63	30/17	11/15	2	1	3	6
Kaur, Marpreet 2015 [21]	India	UKBB	69.6	H&Y, UPDRS	40	40	58.6	58.4	NR	NR	3	1	3	7
Kuporsmith 1982 [23]	USA	NR	NR	H&Y	28	28	62	58	NR	NR	2	1	2	5
Li 2004 [26]	China	CNCESD	56.4	UPDRS, H&Y, HDS	140	120	62.2	59.9	32/38	28/32	3	1	3	7
Miri 2016 [22]	USA	UKBB	NR	MMSE	20	16	66.3	66.5	NR	NR	3	2	3	8
Okuda 1995 [10]	Japan	NR	52.4	H&Y, MMSE	42	44	67.4	70.3	8/14	11/11	2	1	3	6
Okuda 1996 [24]	Japan	NR	52.9	H&Y, MMSE	36	24	65.7	67.3	NR	NR	2	1	3	6
Peppe 1995 [27]	Italy	NR	13.3	UPDRS, H&Y	36	16	62.5	61.2	NR	NR	2	1	3	6
Quagliato 2014 [28]	Brazil	UKBB	83.76	UPDRS, H&Y	86	76	63.1	62.4	27/16	17/21	3	1	3	7
Sagliocco 1997 [17]	Austria	NR	31.25	H&Y, MMSE	34	33	61.94	54.53	8/9	9/8	2	1	3	6
Sartucci 2006 [3]	USA	UKBB	26.4	UPDRS, H&Y	21	24	60.1	46.8	6/6	6/6	3	1	3	7

PD = Parkinson’s disease; HC = healthy controls; NR = not reported; UKBB = United Kingdom Brain Bank clinical diagnostic criteria; UPDRS = Unified Parkinson’s Disease Rating Scale; H&Y = Hoehn and Yahr Scale; SE-ADL = Schwab and England Activities of Daily Living Scale; MMSE = Mini-Mental State Examination; SPES/SCOPA = Short Parkinson’s Evaluation Scale/Scales for Outcomes in Parkinson’s disease; CMA = Chinese Medical Association clinical diagnostic criteria; CNCESD = Chinese National Conference on Extra-Pyramidal System Disease diagnostic criteria; HDS = Hasegawa Dementia Scale.