Table 3.

Mean neuropsychological test z-scores at baseline

Test	Unadjusted beta (SE)			Adjusted beta (SE)*
	PD-MCI	AD-MCI	p-Value	Group difference†	p-Value
MMSE total	−0.28 (0.13)	−1.47 (0.18)	<0.001	0.87 (0.30)	0.003
Logical Memory Immediate	−0.81 (0.00)	−1.20 (0.09)	<0.001	0.47 (0.16)	0.004
Logical Memory Delayed	−0.53 (0.00)	−1.39 (0.10)	<0.001	0.72 (0.15)	<.001
Digit Span Forward	−0.22 (0.09)	−0.44 (0.08)	0.02	0.19 (0.10)	0.06
Digit Span Backward	−0.41 (0.05)	−0.45 (0.08)	0.88	−0.04 (0.09)	0.68
Animals list generation	−0.19 (0.19)	−0.74 (0.05)	0.005	0.35 (0.21)	0.09
Vegetables list generation	−0.50 (0.14)	−0.88 (0.09)	0.26	0.16 (0.18)	0.36
Boston Naming Test	0.35 (0.08)	−0.45 (0.10)	<0.001	0.59 (0.15)	<.001
Trail Making Test A‡	−0.57 (0.13)	−0.38 (0.11)	0.30	−0.32 (0.19)	0.10
Trail Making Test B‡	−0.96 (0.25)	−0.99 (0.13)	0.97	−0.27 (0.26)	0.29
Digit symbol	−0.79 (0.11)	−0.77 (0.10)	0.69	−0.23 (0.13)	0.08
CDR sum of boxes (raw score)	1.43 (0.23)	1.16 (0.10)	0.31	0.25 (0.30)	0.41

Abbreviations: PD-MCI = mild cognitive impairment due to Parkinson's disease; AD-MCI = mild cognitive impairment due to Alzheimer's disease; MMSE = Mini Mental State Exam; CDR = Clinical Dementia Rating

^*Adjusted for age at baseline (years), sex, and education (years)

^†An estimate >0 means that the PD-MCI participants performed better at baseline than the AD-MCI participants

^‡For the Trail Making Tests A and B, a higher score means worse performance; therefore, the Trail Making z-scores have been inverted to be consistent with the other tests, in which a negative score means scoring worse than controls