| 主权项 |
1. A system comprising a cochlear implant device and a screening device communicating with the cochlear implant device,
the cochlear implant device comprising:
an electrode array comprising a plurality of stimulation electrodes to be implanted in a patient's cochlea for electrical stimulation of the cochlea,a stimulation signal unit for generating stimulation signals to be supplied to the stimulation electrodes,a unit for capturing ECAP signals induced at the electrodes in response to stimulation of the cochlea by applying stimulation signals to the electrodes; the screening device being adapted to cooperate with the stimulation signal unit in a manner so as to provide the electrodes with stimulation signals suitable for conducting growth function measurements, recovery measurements and spread-of-excitation measurements, and being adapted to
estimate, for at least part of the electrodes, the threshold current level required for achieving an ECAP-signal based on interpolated growth function measurements of the ECAP-signal at at least four different current levels;conduct recovery measurements for at least some of those electrodes for which an ECAP level of at least 100 μV was measured in the growth function measurements, the recovery measurements comprising ECAP measurements at constant current level as a function of an interpulse interval of the stimulation signal in order to obtain a recovery function for each of the recovery-measured electrodes, and obtain a recovery time constant for each of the recovery-measured electrodes from an exponential fit of the respective recovery function; andconduct a spread-of-excitation (SOE) measurement for at least some of those electrodes for which an ECAP level of at least 100 μV was measured in the growth function measurements, wherein the stimulation current is applied subsequently only to one of the electrodes as the probe electrode while an ECAP level is measured subsequently at each of the valid electrodes in order to obtain a spread-of-excitation function; and obtain, for each electrode used as a probe electrodes a width of electrical stimulation from a fit of the spread-of-excitation function; wherein a measurement point in all measurements is accepted by the screening device as a valid ECAP measurement only if the ECAP signal is at least 50 μV and the signal-to-noise ratio is more than 5 dB, with the noise level being measured at times when there is no electrical stimulation of the cochlea. |
