Table 1

Demographic, clinical and neuropsychological characteristics of the PD-MCI total sample and PD-MCI subtypes

Total PD-MCI
n=269 (100%)
n=18 (6.7%)
n=82 (30.5%)
n=106 (39.4%)
naMCI-md n=63 (23.4%)p Value*†
Age (years)67.8±7.464.3±9.268.2±7.467.5±7.568.5±6.30.37
 M (%)184 (68.4)11 (61.1)46 (56.1)74 (69.8)53 (84.1)0.036 (more women in aMCI-md than in naMCI-md)
 F (%)85 (31.6)7 (38.9)36 (43.9)32 (30.2)10 (15.9)
Education (years)13.4±2.914.1±3.113.0±3.113.4±2.813.7±2.90.42
Age at PD symptom onset (years)59.2±9.257.6±9.058.6±9.859.4±9.459.8±8.10.79
Age at PD diagnosis (years)60.7±8.858.3±8.960.6±8.860.6±9.461.5±8.00.57
Age at PD medication (years)60.9±8.858.3±8.960.9±8.860.9±9.361.6±7.90.57
PD duration (months)84.8±63.573.2±48.190.2±66.783.7±65.183.1±60.90.86
LEDD (mg/day)796.6±497.2763.6±431.2809.5±480.2764.9±485.1842.9±559.90.85
H&Y Stage: median (range)2.0 (1-5)2.0 (1-3)2.0 (1-5)2.0 (1-5)2.0 (1-5)0.51
UPDRS I2.4± 1.91.9±1.63.0± 2.01.9±1.82.4±1.70.0042 (aMCI-md>naMCI-sd)
UPDRS III23.2±11.620.9±9.424.9±11.121.6±11.624.4±12.40.13
UPDRS IV3.1±3.23.0±2.93.4±3.32.9±3.03.0±3.30.74
MMSE28.0±1.728.6±1.627.5±1.828.3±1.528.1±1.80.0084 (aMCI-md<naMCI-sd)
PANDA21.1±5.121.7±4.418.6±5.322.4±4.722.2±4.7<0.0006 (aMCI-md<naMCI-sd and naMCI-md)
 Word list direct recall (CERAD+)‡−0.7±1.4−1.7±1.0−2.1±0.90.1±0.90.0±0.9<0.0006 (aMCI-sd and aMCI-md<naMCI-sd and naMCI-md)
 Word list delayed recall (CERAD+)‡−0.5±1.2−1.3±0.9−1.5±0.90.2±0.90.0±0.9<0.0006 (aMCI-sd and aMCI-md<naMCI-sd and naMCI-md)
 Figure delayed recall (CERAD+)−0.6±1.4−0.3±1.3−1.0±1.4−0.2±1.3−0.6±1.30.018 (aMCI-md<naMCI-sd)
 Digit span forward (WMS-R): centile53.3±29.167.1±27.651.5±31.153.8±28.651.1±27.10.76
 Semantic word fluency (CERAD+)‡−0.4±1.20.3±1.1−0.8±1.0−0.1±1.3−0.6±1.10.003 (aMCI-md<naMCI-sd and naMCI-md)
 Formal-lexical word fluency (CERAD+)‡−0.2±1.10.2±0.9−0.6±1.20.2±1.0−0.5±0.9<0.0006 (aMCI-md and naMCI-md<naMCI-sd)
 MCST categories: T score‡38.1±12.648.2±6.836.2±13.139.2±11.835.3±13.20.0072 (all other subtypes <aMCI-sd)
 MCST non-perseverative errors: T score‡42.1±10.151.1±5.441.4±10.342.2±9.939.9±10.20.0042 (all other subtypes <aMCI-sd)
 MCST perseverative errors: T score‡45.5±9.151.5±6.944.3±10.246.2±7.943.8±9.30.18
 Digit span backward (WMS-R): centile36.1±27.054.8±34.331.5±25.439.3±26.231.6±25.60.12
 Stroop Color Naming: T score‡51.8±7.854.3±10.050.0±8.054.0±6.849.7±7.40.12
 Stroop Word Reading: T score‡50.2±9.654.6±10.647.6±9.153.2±9.647.4±8.30.0168 (aMCI-md and naMCI-md<naMCI-sd)
 Stroop Interference: T score‡52.6±8.956.0±5.349.7±8.856.0±7.549.3±9.5<0.0006 (aMCI-md and naMCI-md<naMCI-sd)
 BTA‡−0.4±1.20.1±0.7−0.8±1.30.0±1.1−0.6±1.3<0.0006 (aMCI-md and naMCI-md<naMCI-sd)
 LPS 50+ subtest 7: T score‡45.9±10.548.8±8.244.1±10.349.1±9.841.8±10.6<0.0006 (naMCI-md<naMCI-sd)
 LPS 50+ subtest 9: T score‡50.6±9.452.2±8.948.1±9.753.3±8.748.4±9.10.0174 (aMCI-md and naMCI-md<naMCI-sd)
 Figure copying (CERAD+)‡−0.3±1.30.1±0.7−0.6±1.30.0±1.3−0.6±1.40.0384 (naMCI-md<naMCI-sd)
 BNT (CERAD+)‡0.2±1.00.4±0.7−0.1±1.10.4±0.9−0.1±1.10.0006 (aMCI-md and naMCI-md<naMCI-sd)
  • Data are indicated as mean (SD) if not indicated otherwise. Neuropsychological data show z scores if not indicated otherwise.

  • *Significant at p≤0.05; in case of significance, Bonferroni-corrected p values are indicated (in that case, the p value was multiplied by 6).

  • †In group comparisons, covariates for sociodemographic variables that are not corrected for in the normative data of the tests (age, education, sex) as well as depression scores were analysed and are reported here.

  • ‡Test is relevant for PD-MCI diagnosis.

  • AES, Apathy Evaluation Scale; aMCI-md; amnestic multiple-domains subtype; aMCI-sd, amnestic single-domain subtype; BNT, Boston Naming Test; BTA, Brief Test of Attention; CERAD+, Consortium to Establish a Registry for Alzheimer’s Disease-Plus; EQ, EuroQol-5D; F, female; GDS, Geriatric Depression Scale; H&Y, Hoehn and Yahr; LEDD, levodopa-equivalent daily dose; LPS 50+, Leistungsprüfungssystem for 50+ aged (subtest 7: spatial rotation, subtest 9: spatial imagination); M, male; MCST, Modified Card Sorting Test; MG, milligram; MMSE-language, Mini Mental State Examination (items 22, 23, 24, 28, 29); naMCI-md; non-amnestic multiple-domains subtype; naMCI-sd, non-amnestic single-domain subtype; PANDA, Parkinson Neuropsychometric Dementia Assessment; PD, Parkinson’s disease; PD-MCI, Parkinson’s disease with mild cognitive impairment; PDQ-39, Parkinson’s Disease Questionnaire 39-item version; TMT-B/A, Trail Making Test-Index: scores of version B divided by scores of version A; UPDRS, Unified Parkinson’s Disease Rating Scale; WMS-R, Wechsler Memory Scale-Revised. For references of the neuropsychological tests, see ref. 18.