Table 2.
MPO and reference thresholds for implantable BCDs
| Device | MPO in force level [dB re 1μN]
|
Comment/reference | ||||
|---|---|---|---|---|---|---|
| 0.5 k | 1 k | 2 k | 4 k | PTA4 | ||
| 1. Bonebridge MPO @ Skullsimulator | 93 | 104 | 102* | 84 | 95.8 | Håkansson B, personal communication, 2014 |
| 2. BCI MPO @ Skullsimulator | 97 | 102 | 94* | 95 | 97.0 | Taghavi et al, unpublished data, 2014 |
| 3. RETFL DBC @ pos A (BAHA) | 48 | 45.5 | 26 | 27.5 | 36.8 | Carlsson and Håkansson79 |
| 4. Correction: Pos A (BAHA) vs pos B (BCI) [dB] | 3 | 9 | 10 | 8 | 7.5 | Reinfeldt et al50 |
| 5. RETFL DBC @ pos B (BCI) | 45 | 36.5 | 16 | 19.5 | 29.3 | Calculated (3 minus 4) |
Notes: Pos A refers to the approximate skull position for a BAHA, 55 mm behind and slightly above the ear-canal opening. Pos B is the skull position for the BCI, 10–15 mm behind the ear-canal opening. Correction (4) is the calculation of the sensitivity difference between stimulation of the BCI and the BAHA positions (pos B and pos A, respectively). @, attached to.
Values were taken slightly below 2 kHz to avoid interference with a resonance peak.
Abbreviations: BAHA, bone-anchored hearing aid; BCI, bone-conduction implant; BCD, bone-conduction device; DBC, direct bone conduction; MPO, maximum power output; pos A, position A; pos B, position B; PTA4, four-frequency pure-tone average; re, relative to; RETFL, reference equivalent threshold force level.