Is the functional decline of Parkinson\u27s disease similar to the functional decline of Alzheimer\u27s disease?

Since many Parkinson\u27s disease (PD) subjects develop dementia, we determined whether the correlation between functional and cognitive decline seen in Alzheimer\u27s disease (AD) is seen in PD. Seventy-five PD subjects with and without dementia and 103 AD/MCI subjects underwent the Functional Assessment Staging (FAST), the Global Deterioration Scale (GDS), the UPDRS motor portion, and the MMSE. In AD/MCI subjects, changes in FAST and GDS scores correlated with MMSE (ρ=-0.814, P\u3c0.001; ρ=-0.840, P\u3c0.001, respectively). In PD subjects, the FAST and GDS also correlated with MMSE (ρ=-0.675, P\u3c0.001; ρ=-0.647, P\u3c0.001, respectively). The UPDRS correlated with the GDS and FAST more closely in PD than in AD. Similar to AD, functional declines in PD correlates with cognitive decline and may be influenced by motor disability in PD. © 2005 Elsevier Ltd. All rights reserved

Functional Ability Correlates With Cognitive Impairment in Parkinson\u27s Disease and Alzheimer\u27s Disease

Background/Aims: Previously we have shown that functional declines in Parkinson\u27s disease (PD) and Alzheimer\u27s 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