Means (SD) for the outcome variables from the EEG measurements (p values for group differences are also presented)
| Variable | Reference group | Groups exposed to aluminium | p Value for mean differences | |||||
|---|---|---|---|---|---|---|---|---|
| Mild steel welders (n=39) | Smelters (n=119) | Flake powder (n=16) | Welders (n=38) | |||||
| Visual ratings: | ||||||||
| Frequency of alpha activity | 9.9 (0.6) | 9.7 (0.8) | 9.9 (0.6) | 9.6 (0.8) | NS | |||
| Pathological EEGs (%) | 13 | 18 | 13 | 29 | NS | |||
| Frequency analysis: | ||||||||
| F3–C3 / F4–C4 | ||||||||
| % Delta | 25.1 (7.7) | 23.2 (6.1) | 22.8 (6.8) | 23.8 (7.7) | NS | |||
| % Theta | 16.1 (3.9) | 17.4 (5.1) | 16.3 (4.0) | 17.1 (4.6) | NS | |||
| % Alpha | 23.2 (11.7) | 23.8 (12.0) | 25.2 (15.9) | 26.9 (16.2) | NS | |||
| % Beta | 13.4 (8.0) | 14.2 (6.2) | 10.9 (5.0) | 11.7 (5.6) | NS | |||
| P3–O1 / P4–O2: | ||||||||
| % Delta | 15.3 (6.9) | 18.2 (8.6) | 17.9 (9.9) | 15.7 (8.6) | NS | |||
| % Theta | 13.9 (4.6) | 17.0 (7.9) | 15.2 (6.6) | 14.5 (6.5) | NS | |||
| % Alpha | 42.8 (17.5) | 40.1 (19.8) | 43.8 (21.5) | 45.3 (22.5) | NS | |||
| % Beta | 14.2 (5.7) | 12.6 (6.6) | 9.5 (3.0) | 12.5 (6.9) | NS | |||