Table 1.
Demographic, clinical, and neuropsychological characteristics of the two PD groups (PDD patients included) as identified by the first hierarchical cluster analysis.
| Total group of PD and PDD |
Cluster-I PD only* |
Cluster-II PD and PDD* |
P value | |
|---|---|---|---|---|
| Number, (%) | 121 (100.0) | 50 (41.3) | 71 (58.7) | |
| Male gender, n (%) | 81 (66.9) | 33 (66.0) | 48 (67.6) | 0.85 |
| Age at evaluation, years | 68.7 ± 6.9 | 66.1 ± 6.7 | 70.6 ± 6.4 | <0.001 |
| Neurological assessment | ||||
| Disease duration, years | 6.6 ± 5.1 | 5.8 ± 4.7 | 7.1 ± 5.2 | 0.17 |
| UPDRS-III motor score (on state) | 28.3 ± 11.5 | 25.3 ± 11.7 | 30.5 ± 11.0 | 0.01 |
| Hoehn and Yahr stage, n (%) | ||||
| 1 | 12 (9.9) | 6 (12.0) | 6 (8.5) | |
| 1.5 | 5 (4.1) | 3 (6.0) | 2 (2.8) | |
| 2 | 49 (40.5) | 24 (48.0) | 25 (35.2) | 0.06 |
| 2.5 | 32 (26.5) | 14 (28.0) | 18 (25.4) | |
| 3 | 16 (13.2) | 3 (6.0) | 13 (18.3) | |
| 4 | 7 (5.8) | 0 (0) | 7 (9.9) | |
| Medication, daily dose | ||||
| Levodopa dose (mg) | 351.4 ± 304.7 | 330.3 ± 343.6 | 366.3 ± 275.6 | 0.55 |
| Levodopa equivalent dose (mg) | 573.8 ± 417.2 | 585.0 ± 470.2 | 566.0 ± 378.8 | 0.35 |
| Antidepressants, n (%) | 28 (23.1) | 9 (18.0) | 19 (26.8) | 0.12 |
| Neuroleptics, n (%) | 14 (11.6) | 1 (2.0) | 13 (18.3) | 0.11 |
| PD patients with dementia, PDD | 24 (19.8) | 0 (0) | 24 (33.8) | <0.001 |
| MMSE (raw score) | 26.6 ± 2.6 | 28.1 ± 1.5 | 25.5 ± 2.6 | <0.001 |
| Beck's Depression inventory | 8.7 ± 5.7 | 7.1 ± 4.7 | 9.9 ± 6.0 | 0.009 |
| Neuropsychiatric inventory | 4.7 ± 7.3 | 3.5 ± 5.5 | 5.5 ± 8.2 | 0.22 |
| Parkinson's disease Questionnaire-PDQ-39 | 5.4 ± 4.2 | 3.4 ± 3.1 | 6.8 ± 4.3 | 0.001 |
| NAI: NAA-ADL inventory, patients' self-assessment |
48.8 ± 32.4 | 67.2 ± 22.0 | 35.9 ± 32.4 | <0.001 |
| NAI: NAB-ADL inventory, caregivers' assessment |
50.3 ± 31.0 | 67.1 ± 25.1 | 38.4 ± 29.4 | <0.001 |
|
| ||||
| Factor scores |
Standardized values of the total PD cohort (PD norms) |
Mean group performance in relation to the standardized values, that is, below (−) versus above (+) the average of the total PD cohort | ||
|
| ||||
| Factor 1, frontal lobe function | 0 ± 1 | 0.41 ± 0.71 | −0.29 ± 1.07 | 0.005 |
| Factor 2, word-list memory and recall | 0 ± 1 | 0.56 ± 0.90 | −0.39 ± 0.87 | <0.001 |
| Factor 3, attention | 0 ± 1 | −0.58 ± 0.87 | 0.37 ± 0.91 | <0.001 |
| Factor 4, logical memory | 0 ± 1 | −0.68 ± 1.06 | 0.48 ± 0.60 | <0.001 |
| Factor 5, praxis and visual perception | 0 ± 1 | −0.92 ± 0.90 | 0.56 ± 0.76 | <0.001 |
| Factor 6, fluency and naming ability | 0 ± 1 | 0.62 ± 0.84 | −0.44 ± 0.86 | <0.001 |
|
| ||||
| Neuropsychological assessment | Mean group performance in relation to the standardized values provided by the test manuals, that is, below (−) and above (+) the average of healthy control subjects | |||
|
| ||||
| Factor 1: | ||||
| Trail Making Test, part B | 49.8 ± 39.3 | 75.2 ± 29.8 | 32.0 ± 35.3 | <0.001 |
| Tower of London | 39.0 ± 26.7 | 48.5 ± 24.0 | 32.3 ± 26.6 | 0.024 |
| NAI: digit span | 56.3 ± 31.4 | 70.3 ± 28.7 | 46.5 ± 29.6 | <0.001 |
| NAI: figure test | 52.1 ± 27.2 | 62.6 ± 20.1 | 44.7 ± 29.1 | 0.006 |
| Berlin Apraxia Test (raw score) | 35.7 ± 5.5 | 38.7 ± 3.2 | 33.7 ± 5.9 | <0.001 |
| Factor 2: | ||||
| CERAD: word-list memory | 29.9 ± 27.3 | 48.5 ± 16.8 | 16.8 ± 20.3 | <0.001 |
| CERAD: word-list recall | 36.9 ± 30.0 | 54.8 ± 29.1 | 24.2 ± 23.7 | <0.001 |
| CERAD: word-list recognition | 40.7 ± 34.5 | 57.2 ± 30.3 | 20.0 ± 32.7 | <0.001 |
| CERAD: word-list intrusion | 42.3 ± 33.7 | 53.7 ± 28.0 | 34.2 ± 34.0 | 0.005 |
| Factor 3: | ||||
| TAP: phasic alertness | 55.4 ± 29.2 | 44.2 ± 25.7 | 63.3 ± 29.1 | 0.001 |
| TAP: Go-Nogo, median RT | 40.5 ± 33.5 | 60.6 ± 29.1 | 26.4 ± 29.0 | <0.001 |
| Factor 4: | ||||
| WMS-R: logical memory I | 24.4 ± 26.2 | 41.9 ± 26.9 | 12.0 ± 17.0 | <0.001 |
| WMS-R: logical memory II | 25.9 ± 26.2 | 45.0 ± 26.1 | 12.5 ± 16.0 | <0.001 |
| Factor 5: | ||||
| CERAD: praxis | 40.2 ± 35.7 | 63.6 ± 29.9 | 23.7 ± 29.8 | <0.001 |
| CERAD: praxis delay | 35.6 ± 35.8 | 59.0 ± 34.8 | 19.2 ± 26.2 | <0.001 |
| VOSP: object decision | 42.4 ± 30.1 | 56.4 ± 29.6 | 32.5 ± 26.5 | 0.001 |
| Factor 6: | ||||
| CERAD: verbal fluency | 30.0 ± 28.1 | 52.8 ± 27.7 | 24.2 ± 21.8 | <0.001 |
| CERAD: Boston naming test | 46.9 ± 33.2 | 63.1 ± 28.1 | 35.4 ± 31.9 | <0.001 |
| Trail Making Test, part A | 45.8 ± 35.4 | 70.2 ± 28.0 | 28.6 ± 29.6 | <0.001 |
Data are given as mean ± SD; lower standard (that is, percentile rank) scores in neuropsychological tests indicate poorer performance except for the MMSE; UPDRS-III: Unified Parkinson's Disease Rating Scale part III; P values are corrected for age and UPDRS-III motor score; %: Percentage; PD: Parkinson's disease; PDD: Parkinson's disease with dementia; LEDD: levodopa equivalence daily dose according to the following conversion rates: 100 mg Levodopa equalling 125 mg Levodopa sustained release, 1 mg Pergolide, 1 mg Pramipexol, 5 mg Ropinirole, 5 mg Rotigotin, 10 mg Bromocriptine, 10 mg Apomorphine, 1/5 Entacapone, 1.5 mg Cabergoline. Additionally, 5% was added to the total Levodopa dose for every 5 mg of Selegiline or 1 mg of Rasagiline, up to a maximum of 10%; MMSE: Minimental State Examination; NAI: Nuernberger Alters Inventar; RT: reaction time; *Grouping of patients with PDD following the first hierarchical cluster analysis.