Table 1.

Comparison of PPMI Internal Norms and Published Age-Normative Data in Participants with Parkinson Disease

	Raw Scores M ± SD	Test Performance Based on Published Norms M ± SD	Test Performance Based on Internal HC Overall Group- Norms M ± SD	Test Performance Based On Internal HC Age-Norms M ± SD	df	F	p
HVLT-R Immediate Recall T-score
Baseline Form 1	24.44 ± 4.98	46.34 ± 10.99	46.43 ± 11.06	46.51 ± 10.72	2	0.10	.902
12-month Form 2	23.72 ± 5.34	46.73 ± 11.57	44.38 ± 11.44	45.04 ± 11.61	2	3.34	.036*a
24-month Form 3	23.67 ± 5.51	45.54 ± 11.22	45.61 ± 10.90	44.65 ± 11.21	2	0.65	.523
36-month Form 4	26.50 ± 5.27	49.48 ± 12.18	46.56 ± 11.64	46.58 ± 13.14	2	3.76	.024*ab
HVLT-R Delayed Recall T-score †
Baseline Form 1	8.36 ± 2.52	46.83 ± 11.75	45.99 ± 10.85	46.58 ± 10.60	2	0.70	.497
12-month Form 2	8.12 ± 2.79	47.07 ± 12.83	46.02 ± 11.13	45.78 ± 11.21	2	0.60	.547
24-month Form 3	8.18 ± 2.97	48.02 ± 12.60	45.92 ± 11.75	45.87 ± 12.19	2	3.95	.020*b
36-month Form 4	9.03 ± 2.73	49.11 ± 12.55	47.40 ± 11.15	45.70 ± 12.73	2	5.33	.005*b
LNS Scaled Score †
Baseline	10.59 ± 2.66	11.49 ± 2.68	9.67 ± 3.10	9.84 ± 3.01	2	35.73	<.001*ab
12-month	10.41 ± 2.63	11.38 ± 2.75	9.44 ± 2.96	9.70 ± 3.00	2	41.43	<.001*ab
24-month	10.28 ± 2.82	11.34 ± 2.88	9.23 ± 3.37	9.59 ± 3.25	2	38.15	<.001*ab
36-month	11.02 ± 2.77	11.32 ± 3.12	9.10 ± 3.27	9.30 ± 3.47	2	1538.78	<.001*abc
JLO Scaled Score †
Baseline Odd Numbered Items	12.77 ± 2.13	12.79 ± 2.76	9.47 ± 3.23	9.66 ± 3.11	2	121.99	<.001*ab
12-month Even Numbered Items	12.39 ± 2.37	12.37 ± 2.90	9.69 ± 2.90	9.11 ± 3.38	2	104.90	<.001*abc
24-month Odd Numbered Items	12.78 ± 2.28	12.88 ± 2.74	9.59 ± 3.29	9.72 ± 3.11	2	125.78	<.001*ab
36-month Even Numbered Items	12.54 ± 2.28	12.61 ± 2.86	10.08 ± 2.99	9.10 ± 3.60	2	95.32	<.001*abc
Semantic Fluency T-Score †
Baseline	20.96 ± 5.34	50.79 ± 9.84	47.90 ± 9.95	47.73 ± 9.60	2	9.92	<.001*ab
12-month	20.94 ± 5.40	50.96 ± 10.45	47.03 ± 10.43	47.95 ± 9.98	2	11.70	<.001*ab
24-month	20.92 ± 5.76	51.03 ± 10.87	47.28 ± 10.58	48.10 ± 10.93	2	10.48	<.001*ab
36-month	22.46 ± 5.29	51.19 ± 10.49	46.94 ± 10.32	47.49 ± 10.22	2	15.72	<.001*ab
SDMT z-score †
Baseline Version 1	48.18 ± 9.73	−0.49 ± 0.86	−0.53 ± 0.92	−0.54 ± 0.87	2	0.44	.647
12-months Version 2	40.90 ± 10.13	−0.46 ± 0.92	−0.58 ± 0.90	−0.51 ± 0.96	2	1.26	.284
24-months Version 1	39.85 ± 11.13	−0.50 ± 0.97	−0.90 ± 1.00	−0.55 ± 1.02	2	13.81	<.001*ab
36-months Version 2	47.85 ± 11.05	−0.47 ± 1.03	−0.67 ± 1.01	−0.70 ± 1.11	2	4.42	.012*ab

Notes: Raw Scores are provided for reference only. Repeated Measures ANOVA was conducted between the three normative groups. PPMI = Parkinson’s Progressive Marker Initiative; HC = Healthy Control; HVLT-R = Hopkins Verbal Learning Test Revised; LNS = Letter Number Sequencing, JLO = Judgment of Line Orientation; SDMT = Symbol Digit Modalities Test; Internally Normed z-scores were derived from the mean of the participant score minus the group mean of the healthy control group, divided by the standard deviation of the group mean of the healthy control group for each measure. The HC Overall Group Norms are based on the mean and standard deviation of the entire HC sample. The HC Age-Based Norms utilized norms from the following age ranges: 30–45, 46–60, 61–75, and 76–90. The z-scores were then converted to T-scores or Scaled Scores for direct comparison with published norms, with the exception of SDMT. T-scores have a mean of 50 with a standard deviation of 10; Scaled Scores have a mean of 10 with a standard deviation of 3; z-scores have a mean of 0 with a standard deviation of 1.

^†indicates the between subjects model was significant, p≤.05

^*indicates a significant difference between normative methods, p≤.05

^aindicates a significant difference between published norms and HC overall group mean-based norms, p≤.05

^bindicates a significant difference between published norms and HC age-based norms, p≤.05

^cindicates a significant difference between HC age-based norms and HC overall group mean-based norms, p≤.05