Basic exposure summary of participants
| Self-reported | HMP measured | |||
| n | % | n | % | |
| Laterality of phone use | ||||
| Right | 18 | 60 | 14 | 47 |
| Left | 3 | 10 | 5 | 16 |
| Both sides | 8 | 27 | 11 | 37 |
| Don't remember | 1 | 3 | ||
| Handedness | ||||
| Right | 24 | 80 | ||
| Left | 6 | 20 | ||
| Ambidextrous | 0 | 0 | ||
| Mean | SD | Mean | SD | |
| Number of calls | 22.7 | 41.6 | 15.2 | 10.4 |
| Ln (number of calls) | 2.3 | 1.3 | 2.5 | 0.8 |
| Average call duration (min) | 18.4 | 65.5 | 23.1 | 22.4 |
| Ln (average call duration) | 3.7 | 2.3 | 2.7 | 1.1 |
Ln, natural logarithm transformation; HMP, hardware modified phone.