TABLE 1.
Baseline characteristics and predictors for PDND and PDID subgroups.
| Characteristic M (SD) | Total sample | PDND | PDID | % Missing at baseline |
| N | 48 | 34 | 14 | 0 |
| PD duration (years) | 8.9 (4.5) | 8.6 (4.4) | 9.5 (5.1) | 0 |
| UPDRS part III | 16.6 (8.1) | 14.4 (7.0) | 21.7 (8.5) | 0 |
| Modified Hoehn and Yahr | 2.2 (0.7) | 2.0 (0.5) | 2.6 (0.7) | 0 |
| Age (years) Range |
71.6 (4.77) 65 – 84 |
70.0 (3.53) 65 – 77 |
75.4 (5.33)*** 66 – 84 |
0 |
| Sex n (% Female) | 21 (43.8) | 13 (38.2) | 8 (57.1) | 0 |
| Education (years) | 14.1 (2.96) | 14.3 (3.20) | 13.6 (2.31) | 0 |
| Gait speed (standardized time in sec) | 0.411 (1.59) | −0.076 (0.635) | 1.59 (2.44)*** | 0 |
| Gait steps (standardized number of steps) | 0.420 (1.55) | −0.082 (0.568) | 1.64 (2.36)*** | 0 |
| Balance (standardized time; sec) | 8.82 (4.40) | 10.2 (3.82) | 5.57 (4.09)*** | 0 |
| Finger dexterity (number of taps in 60 sec) | 114.8 (25.3) | 121.6 (24.6) | 98.2 (19.2)** | 0 |
| Visual acuity (feet)a | 34.9 (15.5) | 32.6 (13.4) | 40.4 (19.2) | 0 |
| Smell (number correct out of 12) | 6.60 (2.92) | 6.94 (2.74) | 5.79 (3.26) | 2.1 |
| APOE n (ε2 + , ε3ε3, ε4 +)b | (6, 35, 7) | (5, 25, 4) | (1, 10, 3) | 0 |
| MTHFR n (CC, CT, TT) | (20, 23, 4) | (14, 17, 3) | (6, 6, 1) | 2.1 |
| Third ventricle volume (cm3)c | 1.08 (0.311) | 0.989 (0.249) | 1.34 (0.324)*** | 2.1 |
| Fourth ventricle volume (cm3)c | 1.25 (0.270) | 1.26 (0.291) | 1.21 (0.210) | 2.1 |
| White matter hyperintensities (cm3)c | 2.54 (2.55) | 2.33 (2.47) | 3.09 (2.77) | 2.1 |
| Cortical thickness (mm) | 2.31 (0.083) | 2.33 (0.073) | 2.25 (0.085)** | 2.1 |
| Systolic orthostatic hypotension (mm Hg) | 8.38 (15.0) | 6.84 (15.2) | 13.3 (14.0) | 12.5 |
| Diastolic orthostatic hypotension (mm Hg) | 2.00 (10.7) | 0.69 (9.44) | 6.20 (13.6) | 12.5 |
| Pulse pressure (mm Hg) | 47.5 (8.33) | 47.1 (8.34) | 48.6 (8.52) | 0 |
| Heart rate (beats/min) | 69.1 (9.85) | 68.8 (9.24) | 69.9 (11.5) | 0 |
| Creatinine (mg/dL) | 84.6 (15.2) | 87.6 (14.4) | 77.4 (15.3)* | 0 |
| Homocysteine (mcmol/L) | 13.5 (3.73) | 13.4 (4.04) | 13.7 (2.96) | 0 |
| Vitamin B12 (pmol/g) | 294.6 (110.7) | 293.1 (102.0) | 298.1 (133.9) | 0 |
| Triglyceride (mmol/L) | 1.12 (0.459) | 1.07 (0.430) | 1.22 (0.525) | 2.1 |
| Cholesterol HDL ratio (mg/dL) | 3.61 (0.825) | 3.49 (0.726) | 3.89 (0.995) | 2.1 |
| Up-regulated metabolite panel | 1.32 (0.532) | 1.17 (0.414) | 1.80 (0.608)*** | 12.5 |
| Down-regulated metabolite panel | 0.853 (0.647) | 0.932 (0.710) | 0.600 (0.281) | 12.5 |
| Immediate word recall (total correct) | 37.2 (10.7) | 39.8 (10.5) | 31.0 (8.87)** | 0 |
| Trail A (sec) | 50.7 (18.3) | 44.1 (12.1) | 66.9 (21.1)*** | 0 |
| Trail B (sec) | 139.5 (78.8) | 113.1 (63.3) | 203.8 (77.5)*** | 0 |
| Simple reaction time (ms) | 383.4 (101.7) | 370.1 (73.3) | 415.7 (148.8) | 0 |
| Four choice reaction time (ms) | 1052.6 (251.7) | 962.3 (141.0) | 1258.9 (325.5)*** | 4.2 |
| Depression (total out of 15) | 1.87 (2.38) | 1.38 (1.60) | 3.07 (3.45)* | 0 |
| NPI-sleep (frequency × severity) | 1.50 (2.75) | 1.82 (3.04) | 0.71 (1.73) | 0 |
| NPI-anxiety (frequency × severity) | 0.54 (1.25) | 0.47 (1.19) | 0.71 (1.44) | 0 |
| Activities of Daily Living (% independence) | 88.6 (8.80) | 91.5 (4.69) | 81.8 (12.3)*** | 0 |
| Body mass index (kg/m2) | 27.4 (5.14) | 26.6 (4.17) | 29.1 (6.82) | 0 |
| SMMSE (total out of 30) | 28.1 (1.70) | 28.6 (1.44) | 26.8 (1.63)*** | 0 |
| MoPaRDS (total out of 8) | 3.04 (1.54) | 2.56 (1.42) | 4.21 (1.19)*** | 0 |
aWhat this person sees at 20 feet, an average person sees at x feet, x reported. bε2ε4 (n = 1) grouped with ε4 + . cnormalized using the proportional approach (area of interest/intracranial volume). PDND, Parkinson’s disease with no dementia; PDID, Parkinson’s disease with incipient dementia; PD, Parkinson’s disease; UPDRS, Unified Parkinson’s Disease Rating Scale; NPI, Neuropsychiatric Inventory Questionnaire; SMMSE, Standardized Mini Mental State Exam; MoPaRDS, Montreal Parkinson Risk of Dementia Scale. Baseline variables for PDID significantly differed from PDND *p < 0.05, **p < 0.01, and ***p < 0.001.