Functional ability correlates with cognitive impairment in Parkinson's disease and Alzheimer's disease.
OBJECTIVE
Previously we have shown that functional declines in Parkinson's disease (PD) and Alzheimer's disease (AD) correlate to global measures of cognitive decline. We now determine if the correlation between cognitive impairment and functional ability in PD is similar to that in AD using individual cognitive measures.


METHODS
93 PD subjects and 124 AD/MCI subjects underwent the Functional Assessment Staging (FAST), the Global Deterioration Scale (GDS), and a neuropsychological battery.


RESULTS
In PD subjects, the FAST and GDS correlated significantly with Rey Auditory Verbal Learning Test (AVLT), Controlled Oral Word Association (COWA), Animal Fluency, and Stroop but not with Clock Draw or Judgment Line Orientation (JLO). In AD/MCI subjects, FAST and GDS correlated with all neuropsychological components except Stroop. In the AD/MCI group, the UPDRS significantly correlated with the FAST, GDS, MMSE, and all neuropsychological parameters except the Stroop. In the PD group, the motor UPDRS significantly correlated significantly with FAST, GDS, MMSE and all neuropsychological parameters except Digit Span, Stroop, Clock Draw and JLO.


CONCLUSIONS
Similar to AD, functional decline in PD correlates with multiple measures of cognitive impairment. Some differences between PD and AD may be explained by the influence of motor disability and declines in visuospatial function in PD.
Sabbagh
M N
MN
The Cleo Roberts Center for Clinical Research, Sun Health Research Institute, Sun City, AZ 85351, USA. marwan.sabbagh@sunhealth.org
Lahti
T
T
Connor
D J
DJ
Caviness
J N
JN
Shill
H
H
Vedders
L
L
Mahant
P
P
Samanta
J
J
Burns
R S
RS
Evidente
V G H
VG
Driver-Dunckley
E
E
Reisberg
B
B
Bircea
S
S
Adler
C H
CH
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications* / Q000503:physiopathology / Q000523:psychology; D003072:Cognition Disorders / Q000150:complications* / Q000503:physiopathology / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D009048:Motor Skills; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications* / Q000503:physiopathology / Q000523:psychology; D018709:Statistics, Nonparametric; D014706:Verbal Learning