Cognitive Profiles in Parkinson’s Disease and Their Relation to Dementia: A Data-Driven Approach
Table 2
Demographic, clinical, and neuropsychological characteristics of the two PD groups (PDD patients excluded) as identified by the second hierarchical cluster analysis.
PDD only
Cluster-I PD only
Cluster-II PD only
value
Number, (%)
24 (19.8)
43 (35.6)
54 (44.6)
Male gender, (%)
18 (75.0)
28 (65.1)
35 (64.8)
0.97
Age at evaluation, years
74.2 ± 5.9
65.7 ± 6.0
68.7 ± 6.5
0.02
Neurological assessment
Disease duration, years
9.5 ± 5.6
5.6 ± 4.3
6.1 ± 4.9
0.66
UPDRS-III motor score (on state)
37.5 ± 11.3
25.3 ± 11.5
26.7 ± 9.6
0.52
Hoehn and Yahr stage, (%)
1
0 (0)
6 (14.0)
6 (11.1)
1.5
0 (0)
3 (7.0)
2 (3.7)
2
7 (29.2)
21 (48.8)
21 (38.9)
0.60
2.5
3 (12.5)
11 (25.6)
18 (33.3)
3
8 (33.3)
2 (4.7)
6 (11.1)
4
6 (25.0)
0 (0)
1 (1.9)
Medication, daily dose
Levodopa dose (mg)
457.2 ± 256.0
323.5 ± 352.6
326.6 ± 277.2
0.57
Levodopa equivalent dose (mg)
665.7 ± 407.8
554.7 ± 435.7
548.2 ± 408.3
0.82
Antidepressants, (%)
7 (29.2)
8 (18.6)
13 (24.1)
0.14
Neuroleptics, (%)
7 (29.2)
1 (2.3)
6 (11.1)
0.67
MMSE (raw score)
23.0 ± 2.7
28.1 ± 1.5
26.9 ± 1.5
0.003
Beck’s Depression Inventory
11.6 ± 6.2
7.1 ± 4.8
8.8 ± 5.8
0.06
Neuropsychiatric inventory
9.5 ± 10.3
3.3 ± 5.1
3.3 ± 5.1
0.73
Parkinson’s disease questionnaire-PDQ-39
10.4 ± 4.2
3.5 ± 3.1
4.9 ± 3.2
0.03
NAI: NAA-ADL inventory, patients’ self-assessment
8.8 ± 16.9
67.6 ± 22.3
51.7 ± 28.9
0.002
NAI: NAB-ADL inventory, caregivers' assessment
11.5 ± 10.3
66.8 ± 24.6
54.4 ± 27.1
0.03
Factor scores
Mean group performance in relation to the standardized values (), that is, below (−) and above (+) the average of the total PD cohort
Factor 1, frontal lobe function
−1.11 ± 0.86
0.32 ± 0.71
0.23 ± 0.92
0.64
Factor 2, word-list memory and recall
−0.76 ± 0.90
0.73 ± 0.84
−0.25 ± 0.77
<0.001
Factor 3, attention
0.61 ± 0.98
−0.56 ± 0.92
0.17 ± 0.85
<0.001
Factor 4, logical memory
0.51 ± 0.67
−0.73 ± 1.13
0.35 ± 0.62
<0.001
Factor 5, praxis and visual perception
0.92 ± 0.70
−0.67 ± 0.90
0.14 ± 0.79
<0.001
Factor 6, fluency and naming ability
−0.86 ± 0.81
0.69 ± 0.81
−0.17 ± 0.84
<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
5.3 ± 15.1
75.9 ± 30.2
48.9 ± 35.0
0.001
Tower of London
14.8 ± 22.0
47.7 ± 25.1
42.9 ± 23.8
0.46
NAI: digit span
39.0 ± 32.2
66.9 ± 29.5
55.6 ± 29.4
0.04
NAI: figure test
26.2 ± 29.4
62.4 ± 21.3
55.3 ± 23.0
0.12
Berlin Apraxia Test (raw score)
29.3 ± 6.6
38.6 ± 3.3
36.4 ± 3.9
0.005
Factor 2:
CERAD: word-list memory
12.7 ± 21.7
51.2 ± 25.6
21.9 ± 19.4
<0.001
CERAD: word-list recall
18.0 ± 24.5
60.2 ± 27.4
26.7 ± 21.8
<0.001
CERAD: word-list recognition
15.5 ± 24.0
62.8 ± 27.8
34.2 ± 33.3
<0.001
CERAD: word-list intrusion
20.8 ± 31.9
56.9 ± 29.0
40.1 ± 32.8
0.008
Factor 3:
TAP: phasic alertness
68.7 ± 32.9
43.6 ± 27.1
59.0 ± 25.9
0.007
TAP: Go-Nogo, median RT
16.5 ± 28.1
60.0 ± 30.1
37.3 ± 30.4
<0.001
Factor 4:
WMS-R: logical memory I
8.5 ± 16.5
43.2 ± 27.9
16.4 ± 18.8
<0.001
WMS-R: logical memory II
7.5 ± 12.2
47.3 ± 27.2
17.1 ± 17.2
<0.001
Factor 5:
CERAD: praxis
13.1 ± 27.4
63.6 ± 31.3
33.7 ± 31.1
<0.001
CERAD: praxis delay
10.3 ± 21.5
58.9 ± 35.2
28.3 ± 30.5
<0.001
VOSP: object decision
19.9 ± 19.6
56.6 ± 29.2
41.1 ± 28.6
0.04
Factor 6:
CERAD: verbal fluency
17.6 ± 20.8
55.4 ± 27.3
28.7 ± 22.3
<0.001
CERAD: Boston naming test
21.3 ± 28.8
64.4 ± 28.3
44.3 ± 30.8
0.001
Trail Making Test, part A
9.0 ± 16.8
71.8 ± 27.3
41.4 ± 30.6
<0.001
Data are given as mean ± SD; lower standard (i.e. percentile rank) scores in neuropsychological tests indicate poorer performance except for the MMSE; UPDRS-III: Unified Parkinson’s Disease Rating Scale part III; values are corrected for age; %: 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.
