Confirmatory Factor Analysis of the Motor Unified Parkinson’s Disease Rating Scale

Table 5

(a) Relative validity of total motor UPDRS and subscales by how PD affects on day-to-day basis ratings*, (b) Relative validity of total motor UPDRS and subscales by PD symptoms severity (n = 170).

(a)  

How Parkinson’s disease affects you on a day-to-day basis? (n = 170)
	No difficulties (n = 27)	Mild difficulties (n = 94)	Moderate difficulties (n = 39)	High levels or extreme difficulties (n = 10)	F ratio*	Relative validity
OFF medications
Total motor UPDRS	18.2^a	23.3^a,b	28.3^b	42.4^c	14.88	35.43
Gait/Posture	21.4^a	27.4^a	39.5^b	53.9^c	15.94	37.95
Tremor	13.3^a	14.7^a	13.6^a	20.5^a	0.95	2.26
Rigidity	7.1^a	14.2^a	15.0^a	30.0^a	6.58	15.67
Right	22.8^a	26.3^a	29.1^a	46.5^b	6.44	15.33
Left	19.3^a	26.8^a,b	33.3^b	49.0^c	7.48	17.81
ON medications
Total motor UPDRS	11.6^a	15.5^a,b	20.5^b	33.7^c	15.73	37.43
Gait/Posture	15.2^a	20.1^a	33.1^b	44.6^c	15.70	37.38
Tremor	7.6^a	8.8^a	7.4^a	10.5^a	0.42**	1.00
Rigidity	2.5^a	7.0^a	7.7^a	22.5^b	8.49	20.21
Right	14.4^a	17.2^a	20.1^a	36.0^b	6.74	16.05
Left	12.6^a	18.7^a,b	23.1^b	44.5^c	10.76	25.62

All scales/subscales are scored so that higher values indicate more severely affected. Possible range for total motor UPDRS score is 0 (best) to 108 (worst). Possible range for subscales is 0 (best) to 100 (worst).
^a, ^b, and ^c means within a row with different letters differ significantly (𝑃≤0.05; Duncan multiple range).
*One way between group ANOVAs of total motor UPDRS or subscale and day-to-day effects of PD.
**Reference subscale = ON medication − Tremor.

(b)  

During the last 6 months, how would you rate the severity of your Parkinson’s disease symptoms?
	No symptoms (n = 4)	Mild symptoms (n = 79)	Moderate symptoms (n = 79)	Severe symptoms (n = 8)	F ratio*	Relative validity
OFF medication:
Total motor UPDRS	14.0^a	21.3^a,b	27.6^b,c	36.1^c	8.28	5.56
Gait/Posture	16.1^a	25.3^a,b	35.6^b,c	43.8^c	7.70	5.17
Tremor	8.8^a	12.9^a	16.1^a	18.8^a	1.49**	1.00
Rigidity	12.5^a	11.8^a	15.9^a	20.8^a	1.64	1.10
Right	22.5^a	25.3^a,b	29.1^a,b	38.1^b	2.11	1.42
Left	8.8^a	23.9^a,b	32.0^b,c	46.9^c	6.57	4.41
ON medication:
Total motor UPDRS	8.8^a	14.1^a,b	19.0^b	31.1^c	9.64	6.47
Gait/Posture	11.6^a	19.2^a,b	27.3^b,c	39.7^c	6.55	4.40
Tremor	1.3^a	7.2^a,b	9.4^a,b	14.4^b	2.66	1.79
Rigidity	6.3^a	4.5^a	9.7^a	12.5^a	3.39	2.28
Right	13.8^a	16.7^a	19.2^a,b	31.9^b	3.03	2.03
Left	8.8^a	16.4^a	22.2^a	44.4^b	8.67	5.82

All scales/subscales are scored so that higher values indicate more severely affected. Possible range for total motor UPDRS score is 0 (best) to 108 (worst). Possible range for subscales is 0 (best) to 100 (worst).
^a, ^b, and ^c means within a row with different letters differ significantly (𝑃≤0.05; Duncan multiple range).
*One way between group ANOVAs of total motor UPDRS or subscale and rating of severity of PD symptoms.
**Reference subscale = OFF medications − Tremor.