Graeme Clark Collection

Permanent URI for this collection

http://hdl.handle.net/11343/375

Filters

1993 - 1997 2
1 1
Reset filters

Settings
Statistics
Citations
End date: 1997 × Start date: 1992 × Subject: cochlear implant × Subject: masking ×

Search Results

Now showing 1 - 2 of 2
  • Item
    Thumbnail Image
    Estimating mechanical responses to pulsatile electrical stimulation of the cochlea
    McAnally, Ken I. ; Brown, Mel ; Clark, Graeme M. ( 1997)
    This study estimated the mechanical response of the cochlea to pulsatile electrical stimulation of the scala tympani of the cat. The auditory nerve compound action potential evoked by an acoustic probe was forward-masked by a train of charge-balanced biphasic current pulses. Masking as a function of probe frequency reflected the excitation pattern of the response to the masker and resembled the spectrum of the electrical stimulus. Both pulse rate and pulse width influenced the degree of masking. The vibration of a region of the basilar membrane was estimated by recording the local cochlear microphonic evoked by biphasic pulses. The amplitude of the cochlear microphonic was proportional to the amplitude of the spectral component of the electrical stimulus to which the local cochlear microphonic was tuned. These results are consistent with the generation of a mechanical response to the electrical stimulus.
  • Item
    Thumbnail Image
    Pattern recognition and masking in cochlear implant patients
    Blamey, P. J. ; Dooley, G. J. (Elsevier Science Publishers, 1993)
    Studies of the temporal course of masking using pulsatile electrical stimulation provide a sensitive new technique for the investigation of central pattern recognition. The masked threshold for a single-pulse probe was studied for several different maskers as a function of the time between the probe and the start of the masker. These experiments showed the gradual development of a temporal pattern in the masked thresholds as the number of pulses in the masker was increased. For a 210 msec masker with pulses at 10 msec intervals, both backward and forward masking thresholds showed a well-defined peak at times 10 msec before and after the masker. Probe pulses presented at these times were probably perceived to be part of the masker pattern and therefore were not easily identified as probe pulses. This conclusion was confirmed by using a masker with pulses at 20 msec intervals. Only backward masking was tested, and the results showed a peak approximately 20 msec before the start of the masker, fitting in with the temporal pattern of the masker.