Information from the voice fundamental frequency (F0) region accounts for the majority of the benefit when acoustic stimulation is added to electric stimulation.
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OBJECTIVES: The aim of this study was to determine the minimum amount of low-frequency acoustic information that is required to achieve speech perception benefit in listeners with a cochlear implant in one ear and low-frequency hearing in the other ear. DESIGN: The recognition of monosyllabic words in quiet and sentences in noise was evaluated in three listening conditions: electric stimulation alone, acoustic stimulation alone, and combined electric and acoustic stimulation. The acoustic stimuli presented to the nonimplanted ear were either low-pass-filtered at 125, 250, 500, or 750 Hz, or unfiltered (wideband). RESULTS: Adding low-frequency acoustic information to electrically stimulated information led to a significant improvement in word recognition in quiet and sentence recognition in noise. Improvement was observed in the electric and acoustic stimulation condition even when the acoustic information was limited to the 125-Hz-low-passed signal. Further improvement for the sentences in noise was observed when the acoustic signal was increased to wideband. CONCLUSIONS: Information from the voice fundamental frequency (F0) region accounts for the majority of the speech perception benefit when acoustic stimulation is added to electric stimulation. We propose that, in quiet, low-frequency acoustic information leads to an improved representation of voicing, which in turn leads to a reduction in word candidates in the lexicon. In noise, the robust representation of voicing allows access to low-frequency acoustic landmarks that mark syllable structure and word boundaries. These landmarks can bootstrap word and sentence recognition. (+info)
Contribution of consonant landmarks to speech recognition in simulated acoustic-electric hearing.
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Anosmia associated with hearing loss and benign positional vertigo after head trauma.
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It is well known that head trauma may cause hearing loss, which can be either conductive or sensorineural. Benign paroxysmal positional vertigo and olfactory dysfunction due to head trauma are also well known. The association between sensorineural hearing loss and anosmia, following head trauma, is extremely rare. Two rare cases of post-traumatic occurrence of hearing loss, olfactory dysfunction and benign positional vertigo are reported and the pathophysiology of the association between sensorineural hearing loss, anosmia and benign paroxysmal positional vertigo, after head injury, are briefly discussed. ENT specialists should, in the authors' opinion, be aware of the possible association between anosmia, sensorineural hearing loss and benign paroxysmal positional vertigo after head injury, even in the absence of skull fracture. (+info)
Neuro-otologic manifestations of multiple sclerosis.
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BACKGROUND: Multiple sclerosis (MS) has numerous neurologic signs and symptoms, including hearing impairment. The reports concerning the type and severity of hearing loss in MS patients vary and little is known about an association of the disease characteristics with changes in hearing status. OBJECTIVE: To find the otologic and neuro-otologic manifestations of MS with the use of routine hearing assessment tools. METHODS: The presence of neuro-otologic signs and symptoms were studied in 30 patients diagnosed with MS. Patients underwent pure tone audiometry, speech audiometry and acoustic brain stem response (ABR) tests. The results were compared with 30 healthy age and sex matched controls. RESULTS: The most common finding was sensory-neural hearing loss followed by dizziness and nystagmus. The shape of the audiogram and severity of hearing loss was associated with both chronicity and disease activity. There were abnormal latencies in ABR waves which were more significant with high velocity stimulus. CONCLUSION: Hearing status deserves careful attention in MS patients. It may be used as a diagnostic means or an indicator for evaluating the characteristics of the underlying disease. (+info)
The effects of frequency-place shift on consonant confusion in cochlear implant simulations.
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