Table 2.
Duration of deafness and stimulation histories1 for the 30-day deafened animals studied at 8 months of age and for the comparison group of neonatally deafened cats, matched by age at study and duration of stimulation.
| Cat No. | Neomycin (days) | Age at stimulation, weeks | Stimulation period, weeks | Stimulus | Age at study, wks |
|---|---|---|---|---|---|
| 30 day deafened | |||||
|
| |||||
| K146 | 18 | 8 | 30 | 39 | |
| K149 | 19 | 8 | 29 | 37 | |
| K198 | 19 | 8 | 15 | 1,2: 325pps/30Hz | 23 |
| K446 | 24 | 9 | 18 | 3,4: 325pps/60Hz | 27 |
| K455 | 19 | 8 | 28 | 36 | |
| K200 | 22 | 9 | 30 | 39 | |
| Mean | 20.2 | 8.3 | 25 | 34 | |
|
| |||||
| Neonatally deafened | |||||
| K76 | 20 | 7 | 13 | 1,2: 300 pps/30 Hz | 20 |
| K84 | 19 | 10 | 28 | 1,2: SP | 44 |
| K98 | 20 | 7.5 | 32.5 | 1,2: SP | 40 |
| K105 | 20 | 9 | 29 | 1,2&3,4: 800pps/20Hz | 38 |
| K107 | 18 | 9 | 22 | 1,2&3,4: 800pps/60Hz | 31 |
| K130 | 21 | 7 | 30 | 1,2&3,4:100–800pps/50Hz | 37 |
| Mean | 19.7 | 8.25 | 25.8 | 35 | |
Three animals received bipolar stimulation with amplitude modulated (AM) signals on both apical and basal electrode pairs. Stimuli for K130 were presented on the apical channel for 2 hours each day followed by 2 hours on the basal channel and stepped through four temporally challenging signals (100 pps unmodulated, 300 pps/30 Hz, 500 pps/40 Hz and 800 pps/50 Hz) each presented on 5 consecutive days. This sequence was repeated throughout the chronic stimulation period. K105 and K107 were stimulated on both channels using a carrier rate of 800 pps, sinusoidally amplitude modulated at 20 Hz (K105) or 60 Hz (K107). K84 and K98 received stimulation on a single bipolar channel of the implant from an operational analog CI speech processor (SP in table 2), set at maximum stimulus amplitude of 6 dB above EABR threshold. K76 received monopolar stimulation via a ball electrode positioned on the round window and activated against a distant ground.