Cognitive Profiles in Parkinson’s Disease and Their Relation to Dementia: A Data-Driven Approach
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*
value
Number, (%)
121 (100.0)
50 (41.3)
71 (58.7)
Male gender, (%)
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, (%)
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, (%)
28 (23.1)
9 (18.0)
19 (26.8)
0.12
Neuroleptics, (%)
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; 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.
