Background
Methods
Objectives
Design
Settings
Participants
TMT
Medical status and driving history
Defining the healthy population for normative values
On-road driving evaluation
Literacy
Psychophysical components
Statistical methods
Ethical standards
Results
Population description
Determinants | All study participants (n = 404) | Healthy* (n = 197) | “Unhealthy”* (n = 207) | P-value‡
|
---|---|---|---|---|
Median (p5–p95) / % (n) | Median (p5–p95) / % (n) | Median (p5–p95) / % (n) | (Chi2or T-test) | |
Age (years) | 75.4 years (70-84) | 74.8 (70–83) | 75.8 (71–85) | P = 0.025 |
Gender (% male) | 62.6% (n = 253) | 52.8% (n = 104) | 72.0% (n = 149) | P < 0.001 |
Education (% <12 yrs) | 26.2% (n = 106) | 23.3% (n = 46) | 29.0% (n = 60) | P = 0.198 |
Vision
| ||||
Visual acuity (decimal) | 1.0 dec (0.6–1.2) | 1.0 (0.8–1.2) | 1.0 (0.6–1.2) | P = 0.003 |
Visual field (°) | 180° (150–200) | 180 (160–200) | 180 (150–200) | P = 0.106 |
Contrast sensitivity (log[CS])† | 1.72 log(CS) (1.6–1.76) | 1.72 (1.6–1.76) | 1.72 (1.6–1.76) | P = 0.429 |
Functional mobility
| ||||
Timed up-and-go test – TUG (sec) | 8.0 sec (6.0–13.0) | 8.0 (6.0–12.0) | 8.4 (6.0–14.8) | P < 0.001 |
Cognitive state
| ||||
MoCA (points [0-30]) | 27 points (21–30) | 28 (26–30) | 25 (20–29) | P < 0.001 |
MoCAmod (points [0-29]) | 26 points (20–29) | 27 (24–29) | 24 (19–28) | P < 0.001 |
Driving
| ||||
Distance driven per week (km) | 200 km (50–500) | 200 (40–500) | 200 (50–500) | P = 0.832 |
History of accidents during the previous 2 years | ||||
All types with material damage
| 26.0% (n = 105) | 25.4% (n = 50) | 26.6% (n = 55) | P = 0.785 |
Responsible for damage to others
| 7.4% (n = 30) | 6.6% (n = 13) | 8.2% (n = 17) | P = 0.536 |
Injured
| 1.2% (n = 5) | 0% (n = 0) | 2.4% (n = 5) | P = 0.028 |
On-road driving performance | P = 0.605 | |||
Excellent
| 47.0% (n = 190) | 46.2% (n = 91) | 47.8% (n = 99) | |
Good
| 27.0% (n = 109) | 27.9% (n = 55) | 26.1% (n = 54) | |
Moderate
| 20.5% (n = 83) | 21.8% (n = 43) | 19.3% (n = 40) | |
Poor
| 5.4% (n = 22) | 4.1% (n = 8) | 6.8% (n = 14) |
Reference values for the healthy population
TMT-A (seconds) | TMT-B (seconds) | |||||
---|---|---|---|---|---|---|
Mean | SD | Median [p5-p95] | Mean | SD | Median [p5-p95] | |
Gender
| ||||||
Female (n = 93) | 43.8 | 14.6 | 40 [26-68] | 94.5 | 31.2 | 91 [54-157] |
Male (n = 104) | 45.6 | 17.9 | 40 [27-80] | 117.6 | 59.0 | 98 [56-204] |
Age
| ||||||
<75 years (n = 101) | 43.2 | 14.6 | 40 [26-67] | 103.3 | 47.8 | 91 [53-187] |
75 to 79 years (n = 61) | 43.3 | 14.9 | 40 [24-72] | 97.6 | 34.2 | 90 [58-172] |
≥ 80 years (n = 35) | 51.7 | 22.0 | 44 [29-113] | 132.8 | 65.3 | 129 [66-214] |
Education level
| ||||||
> 12 years of schooling (n = 151) | 44.7 | 16.4 | 40 [26-72] | 101.6 | 45.8 | 90 [54-182] |
≤ 12 years of schooling (n = 46) | 44.8 | 16.9 | 42 [28-76] | 123.8 | 56.3 | 102 [70-214] |
Entire healthy population
| 44.8 | 16.5 | 41 [26-74] | 106.7 | 49.2 | 93 [54-187] |
Literacy versus years of education
Psychophysical properties of the TMT-B
TMT-B | ||
---|---|---|
IRR†[CI95%] | R2
| |
Socio-demographic
| ||
Age (years) | 1.05 [0.91 to 1.20] | 0.006 |
Gender (male) | 1.14 [0.89 to 1.45] | 0.016 |
Education (years of schooling) | 0.91 [0.79 to 1.04] | 0.150 |
Literacy (KHE [sec]) | 1.23 [1.09 to 1.39]* | 0.146 |
Optical tests
| ||
Visual acuity (FrACT arc minutes) | 0.97 [0.88 to 1.06] | 0.004 |
Contrast sensitivity (75% threshold Gabor patch) | 1.12 [1.02 to 1.22]* | 0.075 |
Neuropsychological tasks
| ||
Visio-spatial search (TMT-A [sec]) | 1.25 [1.10 to 1.41]* | 0.157 |
Mental flexibility (Perseverative errors WCST [%]) | 1.11 [0.96 to 1.29] | 0.035 |
Working memory (Digit backwards [n°]) | 0.75 [0.62 to 0.91]* | 0.109 |
Verbal fluency ([animals + fruit–veg.] /2 [n°/min]) | 0.85 [0.73 to 0.98]* | 0.074 |
Functional mobility (timed up-and-go test - TUG [sec]) | 1.11 [0.99 to 1.11] | 0.047 |
Computed tasks
| ||
Visual processing (Vernier’s Task) | ||
Vernier offset (ms)
| 1.12 [0.93 to 1.34] | 0.023 |
Vernier duration (ms)
| 1.12 [0.90 to 1.40] | 0.015 |
Masking effect without shine through SOA 5 (ms)
| 1.11 [0.97 to 1.27] | 0.035 |
Simple response time (ms) | 1.11 [0.93 to 1.32] | 0.029 |
Visual search (RT [ms]) | 1.12 [0.96 to 1.32] | 0.040 |
Motion direction sensitivity (% dots) | 1.17 [1.06 to 1.29]* | 0.125 |
Orientation discrimination sensitivity | 1.17 [1.09 to 1.25]* | 0.091 |
Biological motion | 0.95 [0.80 to 1.13] | 0.005 |
Simon’s effect (Δt [ms]) | 1.03 [0.86 to 1.25] | 0.002 |
On-road evaluation
Determinants | Crude | Model 1-TMT-A | Model 2-TMT-B | |||
---|---|---|---|---|---|---|
R2 = 0.081 | R2 = 0.107 | |||||
OR [CI95%, p-value] | R2
| ORadj
| P-value | ORadj
| P-value | |
Neuropsychological tasks
| ||||||
TMT-A* | 5.1 [1.5 to 17.4, p = 0.010] | 0.036 | 3.8 | 0.041 | - | - |
TMT-B* | 7.6 [2.2 to 25.8, p = 0.001] | 0.058 | - | - | 6.3 | 0.005 |
MoCA | 0.043 | |||||
NoCI (MoCA ≥ 26) | Reference | |||||
MCI (MoCA < 26 & ≥19) | 0.60 [0.20 to 1.8, p = 0.368] | |||||
SCI (MoCA < 19) | 16.7 [2.2 to 127, p = 0.006] | |||||
MoCAmod*† | 4.4 [1.4 to 13.7, p = 0.010] | 0.034 | - | - | ||
Socio-demographic
| ||||||
Age* | 1.6 [0.43 to 6.0, p = 0.468] | 0.003 | 0.85 | 0.821 | 0.83 | 0.797 |
Gender (female) | 2.1 [0.88 to 5.0 p = 0.093] | 0.016 | - | - | - | - |
Education (<12 yrs) | 0.81 [0.3 to 2.3, p = 0.701] | <0.001 | - | - | 0.59 | 0.349 |
Functional mobility
| ||||||
Timed up-and-go test (TUG) | 3.2 [0.9 to 11.1, p = 0.066] | 0.020 | 2.4 | 0.178 | 2.2 | 0.210 |
Driving experience
| ||||||
Distance driven per week*† | 5.4 [1.6 to 17.4, p = 0.004] | 0.043 | 4.1 | 0.022 | 3.9 | 0.031 |
Vision
| ||||||
Visual acuity*† | 1.5 [0.44 to 5.3, p = 0.514] | 0.002 | - | - |