Table 4.
Cognitive performance over time in Parkinson’s disease
| Men (N = 277) | Women (N = 146) | ||||||||||||||
| Variable | Baseline (N = 277) | Month 12 (N = 261) | Month 24 (N = 248) | Month 36 (N = 239) | Month 48 (N = 230) | Month 60 (N = 210) | Baseline (N = 146) | Month 12 (N = 136) | Month 24 (N = 130) | Month 36 (N = 127) | Month 48 (N = 117) | Month 60 (N = 107) | p Interaction (Sex vs Time)** | p Time | Time effect |
| Cognition by testing | |||||||||||||||
| MCI or Dementia (ref group) | 9 (14%) | 32 (19%) | 40 (17%) | 53 (23%) | 49 (23%) | 45 (23%) | 6 (15%) | 17 (17%) | 19 (15%) | 16 (13%) | 10 (9%) | 12 (12%) | 0.082 | 0.780 | 0.99 |
| Normal Cognition | 56 (86%) | 133 (81%) | 198 (83%) | 178 (77%) | 168 (77%) | 151 (77%) | 34 (85%) | 84 (83%) | 108 (85%) | 107 (87%) | 103 (91%) | 88 (88%) | |||
| Missing | 212 | 96 | 10 | 8 | 13 | 14 | 106 | 35 | 3 | 4 | 4 | 7 | |||
| Investigator Diagnosis of Cognitive State | |||||||||||||||
| MCI or Dementia (ref group) | 9 (14%) | 27 (16%) | 45 (18%) | 60 (25%) | 59 (26%) | 48 (24%) | 0 (0%) | 13 (13%) | 16 (13%) | 20 (16%) | 16 (14%) | 13 (12%) | 0.938 | < 0.001 | 0.86 |
| Normal Cognition | 56 (86%) | 143 (84%) | 200 (82%) | 179 (75%) | 166 (74%) | 156 (76%) | 41 (100%) | 88 (87%) | 111 (87%) | 105 (84%) | 99 (86%) | 92 (88%) | |||
| Missing | 212 | 91 | 3 | 0 | 5 | 6 | 105 | 35 | 3 | 2 | 2 | 2 | |||
| MocA | |||||||||||||||
| Mean (SD) | 26.9 (2.4) | 25.9 (2.9) | 26.0 (3.2) | 26.0 (2.9) | 26.2 (3.4) | 26.2 (3.7) | 27.5 (2.2) | 27.1 (2.6) | 26.8 (3.1) | 27.1 (3.1) | 26.9 (3.9) | 27.3 (3.0) | 0.518 | < 0.001 | –0.15 |
| Min–Max | 17.0–30.0 | 15.0–30.0 | 9.0–30.0 | 13.0–30.0 | 13.0–30.0 | 2.0–30.0 | 17.0–30.0 | 18.0–30.0 | 16.0–30.0 | 14.0–30.0 | 11.0–30.0 | 15.0–30.0 | |||
| Missing | 3 | 4 | 3 | 0 | 4 | 4 | 0 | 1 | 0 | 3 | 2 | 2 | |||
| HVLT Immediate recall | |||||||||||||||
| Mean (SD) | 23.6 (4.9) | 23.2 (5.3) | 23.0 (5.3) | 23.8 (5.9) | 22.8 (5.7) | 23.6 (6.6) | 26.1 (4.7) | 25.0 (5.4) | 25.2 (5.4) | 26.4 (6.1) | 26.1 (5.6) | 26.1 (5.8) | 0.879 | 0.230 | –0.07 |
| Min–Max | 9.0–35.0 | 4.0–36.0 | 9.0–35.0 | 6.0–36.0 | 6.0–36.0 | 5.0–36.0 | 13.0–36.0 | 8.0–36.0 | 10.0–36.0 | 7.0–36.0 | 8.0–36.0 | 4.0–36.0 | |||
| Missing | 0 | 3 | 0 | 0 | 5 | 4 | 1 | 0 | 0 | 2 | 2 | 2 | |||
| HVLT delayed recall | |||||||||||||||
| Mean (SD) | 8.0 (2.6) | 7.7 (2.8) | 7.9 (2.9) | 7.9 (3.1) | 7.5 (3.2) | 8.1 (3.3) | 9.1 (2.2) | 8.9 (2.9) | 8.8 (2.9) | 9.1 (2.8) | 9.3 (2.7) | 9.3 (2.9) | 0.921 | 0.743 | –0.01 |
| Min–Max | 0.0–12.0 | 0.0–12.0 | 0.0–12.0 | 0.0–12.0 | 0.0–12.0 | 0.0–12.0 | 3.0–12.0 | 0.0–12.0 | 0.0–12.0 | 0.0–12.0 | 0.0–12.0 | 0.0–12.0 | |||
| Missing | 0 | 3 | 0 | 0 | 5 | 4 | 1 | 0 | 0 | 3 | 2 | 2 | |||
| Benton Judgement of Line Orientation | |||||||||||||||
| Mean (SD) | 13.1 (2.0) | 12.8 (2.1) | 13.1 (2.1) | 13.0 (2.1) | 13.1 (2.0) | 12.6 (2.3) | 12.1 (2.2) | 11.5 (2.7) | 12.2 (2.5) | 11.8 (2.5) | 12.5 (2.6) | 11.9 (2.3) | 0.132 | 0.035 | –0.05 |
| Min–Max | 6.0–15.0 | 5.0–15.0 | 0.0–15.0 | 5.0–15.0 | 5.0–15.0 | 4.0–15.0 | 5.0–15.0 | 2.0–15.0 | 4.0–15.0 | 3.0–15.0 | 2.0–15.0 | 5.0–15.0 | |||
| Missing | 0 | 3 | 3 | 0 | 5 | 5 | 1 | 0 | 1 | 3 | 4 | 3 | |||
| Symbol Digit Modalities Test | |||||||||||||||
| Mean (SD) | 40.0 (9.6) | 39.8 (10.2) | 38.4 (10.7) | 38.2 (11.4) | 37.8 (12.7) | 37.8 (12.5) | 43.4 (9.5) | 42.7 (10.0) | 43.0 (11.2) | 43.2 (11.5) | 42.0 (11.4) | 43.6 (12.3) | 0.237 | < 0.001 | –0.49 |
| Min–Max | 7.0–76.0 | 5.0–70.0 | 5.0–75.0 | 3.0–63.0 | 2.0–102.0 | 0.0–69.0 | 15.0–82.0 | 14.0–62.0 | 2.0–68.0 | 0.0–65.0 | 0.0–63.0 | 1.0–74.0 | |||
| Missing | 0 | 3 | 0 | 0 | 5 | 4 | 1 | 0 | 0 | 4 | 2 | 2 | |||
| Letter Number Sequencing | |||||||||||||||
| Mean (SD) | 10.5 (2.7) | 10.3 (2.8) | 10.2 (2.7) | 10.1 (3.0) | 9.8 (3.2) | 9.7 (3.0) | 10.7 (2.6) | 10.5 (2.5) | 10.6 (2.9) | 10.4 (3.1) | 10.8 (3.1) | 10.7 (2.7) | 0.027 | M: < 0.001 | M: –0.19 |
| Min–Max | 3.0–20.0 | 2.0–18.0 | 2.0–17.0 | 2.0–19.0 | 0.0–20.0 | 2.0–20.0 | 2.0–20.0 | 3.0–16.0 | 2.0–19.0 | 1.0–17.0 | 0.0–18.0 | 2.0–18.0 | W: 0.160 | W: –0.06 | |
| Missing | 0 | 4 | 0 | 0 | 5 | 4 | 1 | 0 | 0 | 2 | 2 | 2 | |||
| Semantic Fluency | |||||||||||||||
| Mean (SD) | 46.3 (11.0) | 46.5 (11.2) | 46.7 (12.7) | 46.0 (10.9) | 45.1 (11.5) | 45.1 (12.6) | 53.1 (11.6) | 53.1 (10.7) | 53.3 (12.4) | 52.5 (12.3) | 53.8 (12.8) | 54.9 (12.1) | 0.037 | M: 0.001 | M: –0.39 |
| Min–Max | 20.0–91.0 | 18.0–97.0 | 18.0–95.0 | 18.0–86.0 | 11.0–83.0 | 7.0–90.0 | 26.0–103.0 | 22.0–81.0 | 15.0–87.0 | 9.0–91.0 | 15.0–84.0 | 11.0–88.0 | W: 0.590 | W: 0.11 | |
| Missing | 0 | 4 | 0 | 0 | 5 | 4 | 1 | 0 | 0 | 2 | 2 | 2 | |||
Note: All models are also adjusted for Baseline BMI, Vascular Risk Factor Score (VRF) and Side Most Affected. Significance level for comparisons is p < 0.006 (after Bonferroni correction). **If interaction is significant, we find time effect p-value for each men and women separately. Otherwise, we provide time effect p-value without stratifying by gender. 1) After adjusting for VRF Scores and side most affected, a significant quantitative interaction is present where men are decreasing in mean Letter Number Sequencing z-score over time, with men experiencing a stronger decrease and women with no significant decrease. For every year increase, the mean Letter Number Sequencing z-score decreases by a multiplicative factor of –0.19 in men, compared to –0.06 in women. 2) After adjusting for VRF Scores and side most affected, a significant qualitative interaction is present where men are decreasing in mean Semantic Fluency z-score over time and women with no significant increase. For every year increase, the mean Semantic Fluency z-score decreases by a multiplicative factor of –0.39 in men, compared to an increase of 0.11 in women.