Table 3.

Number of correct responses: Unadjusted sample means and adjusted difference in means, for patients with Parkinson’s disease versus patients with essential tremor.

	Unadjusted mean number of correct responses		Adjusted difference in mean number of correct responses
	PD (N = 63)	ET (N = 53)	$\widehat{\beta }$ a SE	95% CI	P valueb
Phonological fluency	38.4	31.8	5.3 2.0	[1.3, 9.3]	.01
Category fluency	38.2	33.8	4.1 1.6	[1.0, 7.2]	.01
Category switching	12.5	12.1	0.3 0.5	[−0.8, 1.3]	.59

Note. PD = Parkinson’s disease; ET = Essential Tremor; $\widehat{\beta }$ = coefficient of Diagnosis (PT or ED) term from multivariable regression model; SE = standard error; CI = confidence interval.

^a$\widehat{\beta }$ represents the difference in mean number of correct responses, i.e. mean number of correct responses for PD patients – mean number of correct responses for ET patients, adjusted for Age, Gender, Years of Education, and Premorbid Intelligence. Statistical inference was based on linear regression with robust variance estimation.

^bNull hypothesis: β = 0.

Signifiant levels are bolded.