Objective:

Parkinson’s disease with dementia (PDD) and dementia with Lewy bodies (DLB) show similar neuropathology, fluctuation in attention and treatment response to cholinesterase inhibitors. DLB can be associated with profound visuo-perceptive changes but this domain in PDD is poorly investigated.

Design:

Comparative study of visual-perception in three demented patient groups (PDD, DLB, Alzheimer’s disease (AD)) and two non-demented control groups (Parkinson’s disease without dementia (PD) and healthy elderly controls (controls)).

Material and Methods:

Basic (length, size, orientation discrimination and motion perception) and complex (specific counting, position and form discrimination and overlapping figure identification) visual functions and attention (simple and choice reaction times, digit vigilance) were assessed with a Cognitive Drug Research (CDR) computerized battery in 83 age and education matched subjects (20 controls, 17 PD, 15 AD, 12 DLB and 19 PDD) from the Newcastle MRC prospective cohort study.

Results:

Preliminary results revealed significant impairment in visual-perception and attention in PDD patients compared to controls and PD. No differences were found between PDD and DLB. PDD differed from AD in form discrimination and overlapping figure identification, but not in basic visual functions.

 

	PDD vs Controls	PDD vs PD	PDD vs DLB	PDD vs AD
Attention
simple reaction time	p < 0.001	p = 0.001	ns	ns
choice reaction time	p < 0.001	p < 0.001	ns	p = 0.013
digit vigilance	p < 0.001	p < 0.001	ns	p < 0.001
Basic visual functions
length discrimination	p = 0.004	p = 0.04	ns	ns
size discrimination	p = 0.026	p = 0.08	ns	ns
angle discrimination	p < 0.001	p < 0.001	ns	ns
motion perception	ns	ns	ns	ns
Complex visual functions
specific counting	p < 0.001	p < 0.001	ns	ns
position discrimination	p = 0.001	p = 0.006	ns	ns
form discrimination	p < 0.001	p = 0.001	ns	p = 0.026
overlapping figures	p < 0.001	p < 0.001	ns	p = 0.019

Mann-Whitney-U tests

Conclusion:

Visual-perception and attention are impaired in PDD compared to PD and controls, changes being similar to those seen in DLB. These findings are consistent with previous functional neuroimaging findings in PDD and DLB reporting profound occipital and temporo-parietal dysfunction and support the proposal that the two clinical syndromes fall on a common spectrum of LB disease.