Outcomes of unilateral idiopathic sudden sensorineural hearing loss: Two decades of experience

Objectives(a) Determine the demographic and medical risk factors for patients who presented with unilateral idiopathic sudden sensorineural hearing loss (ISSNHL); (b) identify treatments that patients underwent; (c) evaluate the adequacy of follow‐up and compliance with long‐term hearing rehabilitation.MethodsRetrospective review of patients who presented with unilateral ISSNHL between January 1998 and December 2017 at a tertiary care academic medical center.ResultsTwo hundred‐four patients met inclusion criteria. Of these, 129 (63.2%) did not undergo treatment at an outside hospital prior to our evaluation. In this subgroup, the average pretreatment pure tone average (PTA) was 61.9 ± 2.5 dB (dB). The most common treatment was oral steroids and was recommended in 76 patients (59.9%). Patients also underwent intratympanic (IT) steroid injections (7.2%) or oral steroids followed by salvage IT injections (19.4%). Mean follow‐up duration was 17.9 (±29.2) months, and posttreatment PTA (45.6 ± 2.6 dB) was significantly better than baseline (P < .001). In this cohort, hearing amplification was infrequently recommended. Less than 20% of patients reported active hearing amplification use at their most recent visit. At follow‐up, 90 patients (69.8%) reported subjective improvement in hearing after treatment. Only 55 patients (42.6%) showed improvement in PTA compared to their pretreatment audiograms.ConclusionMany patients with ISSNHL experienced audiometric improvement after treatments, but most had persistent hearing loss. The duration of follow‐up was short. Most patients did not use long‐term hearing amplification. Future studies are needed to identify factors that contribute to reduced follow‐up and low compliance with hearing amplification use in ISSNHL.Level of Evidence2c.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152919/1/lio2331_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152919/2/lio2331.pd

Multichannel Place Pitch Sensitivity in Cochlear Implant Recipients

Cochlear implant recipients perceive a rise in pitch when the site of stimulation is moved from the apex toward the base. The place pitch sensitivity is typically measured using the stimulation of single channels. However, all current cochlear implant devices stimulate multiple channels simultaneously or with pulses temporally interleaved. The primary goal of the present study is to test whether the sensitivity of a cochlear implant recipient to changes in perceived pitch associated with changes of place of excitation improves or deteriorates when the number of active channels is increased, compared with stimulation with only one active channel. Place pitch sensitivity was recorded in four Nucleus CI24 subjects as a function of number of active channels (from 1 to 8). Just noticeable differences were estimated from a constant stimuli 2AFC pitch-ranking experiment with roving loudness. Reference and comparison stimuli contained the same number of active channels but were shifted one or two electrodes toward the base or toward the apex. The place pitch sensitivity was measured using monopolar stimulation at two locations along the electrode array. To minimize cues related to loudness, the multichannel stimuli were loudness balanced relative to the single-channel stimuli presented at C-level. The number of active channels did not affect place pitch sensitivity. This is consistent with a model that compares the edges of the excitation pattern irrespective of the overlap between excitation patterns. There was a significant difference in sensitivity to place pitch among subjects. The average just noticeable differences of place pitch, extrapolated from a fitting procedure, for the subjects ranged from 0.25 mm to 0.46 mm

A Model of Incomplete Adaptation to a Severely Shifted Frequency-to-Electrode Mapping by Cochlear Implant Users

In the present study, a computational model of phoneme identification was applied to data from a previous study, wherein cochlear implant (CI) users’ adaption to a severely shifted frequency allocation map was assessed regularly over 3 months of continual use. This map provided more input filters below 1 kHz, but at the expense of introducing a downwards frequency shift of up to one octave in relation to the CI subjects’ clinical maps. At the end of the 3-month study period, it was unclear whether subjects’ asymptotic speech recognition performance represented a complete or partial adaptation. To clarify the matter, the computational model was applied to the CI subjects’ vowel identification data in order to estimate the degree of adaptation, and to predict performance levels with complete adaptation to the frequency shift. Two model parameters were used to quantify this adaptation; one representing the listener’s ability to shift their internal representation of how vowels should sound, and the other representing the listener’s uncertainty in consistently recalling these representations. Two of the three CI users could shift their internal representations towards the new stimulation pattern within 1 week, whereas one could not do so completely even after 3 months. Subjects’ uncertainty for recalling these representations increased substantially with the frequency-shifted map. Although this uncertainty decreased after 3 months, it remained much larger than subjects’ uncertainty with their clinically assigned maps. This result suggests that subjects could not completely remap their phoneme labels, stored in long-term memory, towards the frequency-shifted vowels. The model also predicted that even with complete adaptation, the frequency-shifted map would not have resulted in improved speech understanding. Hence, the model presented here can be used to assess adaptation, and the anticipated gains in speech perception expected from changing a given CI device parameter