Table 5.
Grooved pegboard and kinematic motor outcomes, overall and by community, Gauteng province, South Africa, 2016–2020
| All participants N = 716 |
Mn smelter community (Meyerton) N = 621 |
Reference community (Ethembalethu) N = 95 |
|
|---|---|---|---|
| Mean (SD) | Mean (SD) | Mean (SD) | |
| Grooved pegboard test, time (seconds)a | |||
| Dominant hand | 108.0 (43.1) | 107.0 (43.0)b | 114.6 (43.4)c |
| Minimum | 43.2 | 43.2 | 59.2 |
| 25th percentile | 80.2 | 79.9 | 82.0 |
| Median | 93.8 | 93.5 | 114.0 |
| 75th percentile | 124.8 | 120.1 | 141.2 |
| Maximum | 300.0 | 300.0 | 300.0 |
| Non-dominant hand | 118.0 (47.1) | 117.5 (47.4)b | 121.4 (44.8)c |
| Minimum | 51.4 | 51.4 | 60.0 |
| 25th percentile | 86.9 | 87.1 | 85.1 |
| Median | 103.8 | 103.2 | 114.7 |
| 75th percentile | 131.7 | 130.3 | 150.3 |
| Maximum | 300.0 | 300.0 | 241.1 |
| Kinematic test – finger-tapping mean velocity (degrees/second)a | |||
| Dominant hand | 312.4 (113.2) | 298.2 (106.0)b | 366.6 (123.5)c |
| Minimum | 59.0 | 59.0 | 121.9 |
| 25th percentile | 222.7 | 217.3 | 275.9 |
| Median | 302.7 | 289.7 | 355.8 |
| 75th percentile | 384.6 | 362.2 | 445.5 |
| Maximum | 679.0 | 590.5 | 679.0 |
| Non-dominant hand | 353.3 (119.2) | 338.2 (111.7)b | 411.0 (129.5)c |
| Minimum | 87.8 | 87.8 | 168.5 |
| 25th percentile | 271.2 | 262.6 | 316.3 |
| Median | 342.7 | 326.8 | 412.9 |
| 75th percentile | 426.3 | 399.4 | 509.4 |
| Maximum | 764.4 | 727.0 | 764.4 |
Abbreviations: Mn manganese
a Poorer motor performance is indicated by greater grooved pegboard times and lower finger-tapping velocities
b Excludes 16 participants (grooved pegboard in dominant hand and non-dominant hand) and 275 participants (kinematic test in dominant and non-dominant hand) with missing data
c Excludes two participants (grooved pegboard in dominant and non-dominant hand) and four participants (kinematic test in dominant and non-dominant hand) with missing data