Effects of donepezil on central processing speed and attentional measures in Parkinson's disease with dementia and dementia with Lewy bodies.

BACKGROUND: We examined attention-enhancing effects of the cholinesterase inhibitor donepezil in Dementia with Lewy bodies (DLB) and Parkinson's disease with dementia (PDD) by means of open label study. METHODS: 22 DLBs and 23 PDDs were assessed over 20 weeks using the Cognitive Drug Research Computerized Attentional Tasks. We examined how much closer our patients moved towards being normal for their age by comparing them to a non-demented elderly control sample (n = 183, aged 71-75 years). RESULTS: Donepezil treatment improved power of attention, continuity of attention and reaction time variability. The deficit in responses was moved towards normal by 38 and 56% for power of attention and 22 and 10% for continuity of attention in PDD and DLB, respectively. CONCLUSIONS: Improvements in attention were found with donepezil in PDD and DLB.

A comparison of the efficacy of donepezil in Parkinson's disease with dementia and dementia with Lewy bodies.

BACKGROUND: Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB) overlap in phenomenology and neurochemical deficits. We hypothesised they would not differ in their response to the cholinesterase inhibitor donepezil. METHODS: We recruited 70 subjects, 30 DLB and 40 PDD, in an open label study to compare the efficacy of donepezil in these two patient groups. They were assessed at baseline, 4, 12 and 20 weeks. The main outcome measures were the Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI) and motor sub-section of the Unified Parkinson's Disease Rating Scale (UPDRS III). RESULTS: PDD patients were younger than DLB and had more severe parkinsonism at baseline. The groups were similar on all other variables of interest. By 20 weeks the mean MMSE score increased by 3.9 points in the DLB group and by 3.2 points in PDD. The mean NPI score reduced by 14.6 points for DLB and 12.0 points for PDD. These treatment effects were all significant compared to baseline (p < 0.001) but there were no significant between-group treatment differences (MMSE p = 0.56, NPI p = 0.39). UPDRS III motor scores did not change significantly from baseline values in either group. Although adverse effects were common (69%) they were usually mild and 64 patients (91%) completed the study. The four patients who did withdraw with adverse effects all had a PDD diagnosis. CONCLUSIONS: Donepezil produced similar improvements in cognition and behaviour in DLB and PDD. This supports the hypothesis that the two disorders are closely related clinically and neurobiologically. Larger scale, placebo controlled clinical trials are needed to provide an evidence base to guide the clinical use of cholinesterase inhibitors in Lewy body disease.

What happens when donepezil is suddenly withdrawn? An open label trial in dementia with Lewy bodies and Parkinson's disease with dementia.

BACKGROUND: This open label study was designed to assess the effects of donepezil treatment, its withdrawal and subsequent recommencement on cognitive functioning, behaviour and parkinsonian symptoms in patients with probable dementia with Lewy bodies (DLB) and with Parkinson's disease who subsequently developed dementia (PDD). METHODS: Eight patients with DLB and 11 with PDD were treated with up to 10 mg of donepezil daily for 20 weeks followed by a 6-week withdrawal period. The primary outcome measures were the Mini-Mental State Examination (MMSE), the total Neuropsychiatric Inventory (NPI) and the Unified Parkinson's Disease Rating Scale III. Testing was conducted before dosing, at week 20, at a withdrawal visit and 3 months after recommencement on donepezil. RESULTS: Patients with DLB and PDD showed a significant improvement in cognition with treatment, loss of this improvement on withdrawal and restoration of treatment gains on recommencement. Both groups also demonstrated favourable, behavioural changes with treatment, PDD patients in particular deteriorating significantly after withdrawal. The only NPI symptom domain that showed a consistent significant response to both treatment (positive) and withdrawal (negative) was hallucinations. The medication was well tolerated and parkinsonian features did not alter significantly over the testing sessions. CONCLUSIONS: Our results suggest that treatment with donepezil improves cognition and hallucinations without increasing parkinsonian symptoms, and its sudden withdrawal is usually detrimental, producing acute cognitive and behavioural decline. Although recommencement on donepezil appears to reverse this deterioration we do not advise its abrupt discontinuation in this population.

Extrapyramidal features in Parkinson's disease with and without dementia and dementia with Lewy bodies: A cross-sectional comparative study.

Risk factors predicting an increased risk of dementia in Parkinson's disease (PD) are not fully established. The dementia associated with PD (PDD) closely resembles dementia with Lewy bodies (DLB). Based upon a high frequency of non-dopaminergic mediated clinical features in DLB, we predicted that a motor subtype comprising postural instability and balance problems would be more common in PDD. We examined extrapyramidal, cognitive, and affective features in 38 PD, 43 PDD, and 26 DLB patients in a cross-sectional study design. Motor subtype was subdivided into postural-instability gait difficulty (PIGD) or tremor (TD) dominant. The PIGD-subtype was more common in PDD (88% of cases) and DLB (69% of cases) groups compared with the PD group (38% of cases), in which TD and PIGD sub-types were more equally represented (P < 0.001). Although the mean depression scores overall were modest, PDD patients scored significantly higher than PD, but not DLB patients (Cornell; P = 0.006, and Geriatric Depression scale, GDS-15; P = 0.001), while within the PD group, those patients with a PIGD subtype had greater depression scores than the TD subtype (GDS-15; P < 0.05). We conclude that non-dopaminergic motor features are frequent in PDD. Neurodegeneration within the cholinergic system is likely to mediate many of these motor problems, as well as playing a significant role in determining the neuropsychiatric symptomatology of both PDD and DLB.