Parkinson’s Disease

Research Article

Cognitive Training and Transcranial Direct Current Stimulation for Mild Cognitive Impairment in Parkinson’s Disease: A Randomized Controlled Trial

Table 3

tDCS and standard cognitive training + tDCS group cognitive performance at baseline, pos-tintervention, and follow-up.


	tDCS						Pairwise comparison statistics
	Baseline		Post-intervention		Follow-up		Baseline to post-intervention			Baseline to follow-up

Outcome	M	SD	M	SD	M	SD	t	p	^a	t	p	^a
COWAT	30.86	16.14	36	15.11	30.57	17.57	1.86	0.06	0.58	−0.17	0.86	−0.30
SOC	5.50	1.35	6.50	1.62	7	1.88	2.12	0.04^b	−0.13	1.94	0.06	0.14
LNS	14.82	5.99	16.11	6.39	16.18	4.74	1.70	0.09	0.12	1.15	0.25	0.13
Stroop test	21.38	6.76	27.66	10.41	26.52	7.47	2.09	0.04	0.65	2.41	0.02	0.01
HVLT	20.33	8.27	25.33	6.28	23.33	7.45	4.45	0.001^b	0.45	3.71	0.001^b	0.03
Paragraph Recall	4	2.23	6.29	2.05	4.36	1.72	4.73	0.001	1.11	0.70	0.49	0.28
BNT	12.57	1.06	13.71	1.83	13.29	1.67	2.23	0.03^b	0.30	1.63	0.11	0.65
Similarities	22.37	2.68	23.42	2.41	21.38	1.67	1.29	0.20	0.13	−0.76	0.45	−1.25
JLO	21.30	7.90	22.44	5.51	24.59	4.80	0.80	0.43	0.24	2.31	0.02^b	0.18
HVOT	20.99	3.76	22.42	3.45	20.99	3.26	1.68	0.10	0.24	0.00	1	−0.01
MMSE	24.31	1.54	26.02	1.64	25.45	2.43	2.29	0.02^b	1.36	1.84	0.07	0.55
PD-CRS	74.76	17.57	85.04	18.10	79.04	20.59	5.10	0.001^b	0.53	1.51	0.14	−0.06
PDQ-39	23.04	8.45	18.09	5.19	18.21	8.65	−0.96	0.34	0.22	−1.11	0.27	0.37
UPDRS-II	1.27	0.56	1.06	0.66	1.23	0.66	−2.25	0.03^b	0.32	−0.48	0.63	0.24

	Standard cognitive training + tDCS						Pairwise comparison statistics
	Baseline		Post-intervention		Follow-up		Baseline to post-intervention			Baseline to follow-up

Outcome	M	SD	M	SD	M	SD	t	p	^a	t	p	^a
COWAT	37.71	9.88	46.14	4.85	39.86	11.26	3.23	0.002^b	1.33	0.44	0.66	−0.22
SOC	7.43	1.41	9.57	1.64	9.14	2.09	4.62	0.001	0.41	2.29	0.02	0.23
LNS	18.54	2.17	18.87	2.47	18.56	2.60	0.34	0.73	−0.04	0.01	0.99	−0.14
Stroop test	24.52	9.30	30.52	8.29	33.81	9.01	2.23	0.03	0.60	5.76	0.001	0.24
HVLT	26.51	4.08	28.51	5.10	29.94	4.85	1.43	0.16	−0.03	2.59	0.01^b	0.09
Paragraph Recall	6	2.07	8.21	1.38	6.43	2.23	2.30	0.02^b	1.29	3.25	0.002^b	0.57
BNT	13.29	1.59	14.43	0.74	14	0.93	1.75	0.08	0.39	1.83	0.07	0.77
Similarities	21.59	2.49	23.51	1.72	21.02	2.31	2.70	0.01	0.59	2.02	0.06	−0.95
JLO	22.83	5.43	24.55	4.74	22.98	7	1.58	0.12	0.37	0.11	0.91	−0.23
HVOT	23.82	3.79	25.11	3.45	24.11	3.29	1.51	0.14	0.21	1.03	0.78	0.05
MMSE	27.02	1.72	26.87	1.30	27.73	1.33	−0.20	0.84	0.46	1.36	0.18	0.50
PD-CRS	87.08	16.93	98.79	13.03	94.94	18.02	5.30	0.001^b	0.71	2.69	0.01^b	0.10
PDQ-39	20.05	11.74	16.33	7.84	19.48	10.87	−1.82	0.07	0.27	−0.30	0.77	−0.09
UPDRS-II	1	0.48	0.62	0.53	0.77	0.32	−2.51	0.01	0.55	−1.74	0.08	0.51

M = mean; SD = standard deviation; t = t statistic; a = effect size computed using change scores with the control group, positive effect favours corresponding intervention group; b = not statistically significant due to nonsignificant main effect; = ; = ; tDCS = transcranial direct current stimulation; COWAT = Controlled Oral Word Association Test; SOC = Stockings of Cambridge; LNS = Letter-Number Sequencing; HVLT = Hopkin’s Verbal Learning Test; BNT = Boston Naming Test; JLO = Judgement of Line Orientation; HVOT = Hooper’s Visual Orientation Test; MMSE = Mini-Mental State Examination; PD-CRS = Parkinson’s Disease—Cognitive Rating Scale; UPDRS-II = Unified Parkinson’s Disease Rating Scale—section II (ADL); PDQ-39 = Parkinson’s Disease Questionnaire-39.