Bilateral inner ear damage after electrical injury: A case report

Electrical injury occurs as a result of direct contact with an electrical source. We present the case of a 62-year-old male patient, an electrician by profession, who was hit by a high-voltage electrical current while working with cables in proximity to a wet floor. The patient suffered from immediate loss of consciousness and five days later he started complaining of slight hearing loss, persistent vertigo, instability and bilateral tinnitus. A thorough audiological and vestibular examination revealed an extensive bilateral vestibulocochlear dysfunction. The exact pathogenetic mechanisms of inner ear dysfunction after electrical injury have not been fully elucidated, although it is believed that there is significant improvement with time. Long-term follow-up, medical assistance and psychological support are crucial factors for the patient management.     

Auditory maturity and hearing performance in inner ear malformations: a histological and electrical stimulation approach

The objective of this study was to assess the auditory performance of the neural structures in response to controlled electrical stimulation period. A prospective cohort study focused on the intracochlear electrical stimulation parameters and hearing performance of patients suffering different cochlear malformations who were treated by cochlear implants constituted the study design. The study sample constituted 16 patients, suffering profound prelingual hearing impairment, diagnosed on the basis of radiological criteria as having an inner ear malformation, and who underwent cochlear implantation and were followed for 24 months. Patients with common cavities, characterized by fewer nerve structures involved, less epithelial penetration, and deficient cochlear tonotopy distribution showed have higher thresholds and electrical charges than patients with cochlear hypoplasia, who in turn have higher thresholds than patients with minor malformations (p < 0.05). Furthermore, word perception was severely compromised in patients with a common cavity malformation and was also poor in patients with cochlear hypoplasia, who were unable to discriminate more than 50% of the words and relied on visual cues as a necessary aid to communication. Better results were reached by minor malformed inner ears. To conclude, the number of nerve structures involved, epithelial penetration and deficient cochlear tonotopy are responsible of inner ear functionality.     

Non-invasive electrical stimulation of the ear canal as a communication aid in acquired total deafness

Some profoundly deafened patients, who cannot be helped by sound amplification, claim to perceive auditory sensations when alternating currents up to 100 Hz are passed through electrodes applied to the skin of the external ear canal. A portable speech processor has been developed which supplies this current. The signal is a balanced square wave, the frequency of which is proportional to the first formant frequency. The amplitude is proportional to the intensity of voiced sounds. In order to fit the narrow frequency and dynamic range of the electrical stimulus, the speech processor produces a downward frequency transposition and strong limitation of the dynamic range. The device has been tested for (1) discrimination of environmental sounds; (2) question/statement discrimination; (3) identification of vowels and consonants in vowel/consonant/vowel context; (4) lip-reading with and without the prosthesis.     

Bilateral middle ear squamous cell carcinoma and clinical review of an additional 5 cases of middle ear carcinomas

We reported a retrospective review of the clinical records for a 64 year old male patient with bilateral middle ear squamous cell carcinoma (MESCC), and for the five other patients with MESCC treated at our institution during the last 20 years. The patient with bilateral MESCC has survived and remained tumor free for more than 1.5 years after extended radical resection of the secondary tumor combined with intra-arterial and systemic chemotherapy, radiotherapy and immunotherapy. Four patients with unilateral MESCC were treated with multidisciplinary treatment (induction chemotherapy, surgery and radiotherapy), and the remaining patient was treated with radiotherapy and mastoidectomy. Five of the six patients are alive with no evidence of disease. The patient treated with radiotherapy and radical mastoidectomy died of local recurrence 3 years after diagnosis. We suggest that MESCC should be considered when refractory granulation, long-standing otorrhea, otalgia and facial paralysis are observed. Multidisciplinary treatment, including intra-arterial chemotherapy and en bloc resection of the temporal tumor is useful for the treatment of MESCC and will improve the prognosis of patients with this disease.     

Bilateral congenital middle ear cholesteatomas

Congenital middle ear choleslcatomas remain of interest because of their relative rarity and unknown origin. A 4-month-old child presenting with bilateral congenital middle ear cholestcatomas forms the basis for this report. The nature of the epithelial debris found suggests an external origin. An extended transcanal tympanotomy approach for removal, based upon an operative experience of 11 similar ears, will be discussed.     

Bilateral carcinoma of the middle ear

We describe the first reported case of bilateral carcinoma of the middle ear.     

Effects of waveform shape on human sensitivity to electrical stimulation of the inner ear

Psychophysical measures of the electrically stimulated human auditory system were obtained for different types of symmetric and asymmetric charge-balanced waveforms. Absolute detection thresholds of biphasic, pseudomonophasic, and ‘alternating monophasic’ current waveforms delivered by a bipolar intra-cochlear electrode pair were determined for four subjects implanted with the LAURA device. Thresholds for alternating monophasic stimuli, in which anodic and cathodic phases alternated every 5 ms, were 5–8 dB lower than for the biphasic waveforms for all four subjects. For two of the four subjects, thresholds for the pseudomonophasic waveforms were also significantly lower than for the biphasic waveforms. These pseudomonophasic thresholds were greatly affected neither by a 500-μs gap inserted between the two phases, nor by whether the shorter phase preceded or followed the longer one. Loudness balancing measures performed at the most comfortable levels also showed that, for equal loudness, alternating monophasic stimuli required a lower level than biphasic and pseudomonophasic waveforms. For three of the four subjects, the dynamic ranges of the pseudomonophasic (but not alternating monophasic) waveforms were greater than those of the biphasic waveforms. The results demonstrate that thresholds and dynamic ranges of human cochlear implant users can be controlled by manipulating the way in which the charge produced by the initial phase of an electrical pulse is recovered.     

The application of direct current electrical stimulation of the ear and cervical spine kinesitherapy in tinnitus treatment

Objective

The aim of the study was to evaluate the effectiveness of electrical stimulations of the hearing organ in tinnitus treatment adapting the frequency of stimulation according to tinnitus frequency, to assess the influence of cervical spine kinesitherapy on tinnitus, as well as to evaluate hearing after electrical stimulations alone and together with cervical spine kinesitherapy.

Methods

The study comprised 80 tinnitus, sensorineural hearing loss patients (119 tinnitus ears) divided into two groups. In group I (n – 58 tinnitus ears) electrical stimulation of the hearing organ was performed, in group II (n – 61 tinnitus ears) electrical stimulation together with cervical spine kinesitherapy. Hydrotransmissive, selective electrical stimulations were conducted using direct, rectangular current. The passive electrode was placed on the forehead, the active – a silver probe – was immersed in the external ear canal in 0.9% saline solution. The treatment involved fifteen applications of electrical stimulations (each lasted for 4 min) administered three or four times a week (whole treatment lasted approximately 30 days). The evaluation of the results considered a case history (change from permanent to temporary tinnitus), questionnaires (the increase/decrease of the total points) and the audiometric evaluation of hearing level.

Results

Before the treatment, group I comprised 51 ears (87.93%) with permanent, and 7 ears (12.07%) with temporary tinnitus; group II – 55 ears (90.17%) with permanent and 6 ears (9.83%) with temporary tinnitus. After the treatment, in both groups the number of ears with permanent tinnitus decreased considerably obtaining the pauses or disappearing of tinnitus. Directly after the treatment, group I comprised 25 ears (43.11%) with permanent, and 10 ears (17.24%) with temporary tinnitus, in 23 ears (39.65%) tinnitus disappeared; group II – 33 ears (54.1%) with permanent and 11 ears (18.03%) with temporary tinnitus, in 17 ears (27.87%) tinnitus disappeared.Regarding questionnaires, improvement was observed in group I – in 43.11% of ears, in group II – 32.8%. In both groups audiometric improvement of hearing was recognized.

Conclusions

(1) Electrical stimulation of the hearing organ, with the application of current frequencies according to tinnitus frequencies (selective electrical stimulation), was an efficient method in severe tinnitus treatment. (2) Cervical spine kinesitherapy in the treatment of tinnitus, using electrical stimulation, did not have any supporting influence.     

Bilateral ear canal stenosis from retained Goode T-tubes

A 14-year old white male presented with a 2-year history of bilateral otorrhea. Purulent otorrhea with very stenotic external auditory canals (EAC) were found, and the patient was treated with topical otic solutions. Bilateral conductive hearing loss was found on audiometric studies. Biopsies were taken after the patient failed medical treatment. The results were consistent with granulation tissue and chronic inflammation. A CT scan revealed complete bilateral EAC stenosis. At surgery the patient was found to have bilateral retained Goode T-tubes, which were placed at 2 years of age. After removal of the tubes, the patient made a good recovery with improved hearing. This case illustrates a severe complication of retained tympanostomy tubes. Patients with these tubes require close long-term follow-up with careful management of problems such as granulation tissue or otorrhea to prevent this type of complication.     

Testing the diagnostic value of electrical ear canal stimulation in cochlear implant candidates by functional magnetic resonance imaging

Prior to cochlear implant (CI) surgery in children, the integrity of the auditory pathway is sometimes assessed by electrical ear canal stimulation (ECS). However, the evaluation of reactions as auditory is subjective. To test the prognostic value of ECS, functional magnetic resonance imaging (fMRI) was performed during ECS vicariously in 18 adult CI candidates. Activation of the primary auditory cortex was detected in 9 of 16 cases when auditory sensations during ECS occurred, and tended to be more bilaterally distributed in CI candidates than in normal-hearing controls. ECS sensations only tended to correlate with fMRI activations. However, solely frequency discrimination during electrical stimulation predicted CI outcome, but neither other auditory sensations nor fMRI activations did so satisfactorily, which limits the diagnostic value of these measures. Instead, preoperative residual hearing (nonamplified and amplified) was a robust predictor for CI benefit.     

Reanimation of the paralyzed human larynx with an implantable electrical stimulation device

OBJECTIVES/HYPOTHESIS: Electrical stimulation of the posterior cricoarytenoid muscle, when paced with inspiration, offers a physiological approach to restore ventilation in bilateral laryngeal paralysis without any of the disadvantages associated with conventional treatment. STUDY DESIGN: A prospective study of six patients. METHODS: The patients were successfully implanted with an Itrel II stimulator (Medtronic, Inc). In postoperative sessions, stimulated vocal fold abduction, patient ventilation, and voice were assessed and compared with preoperative values. RESULTS: The optimum stimulus paradigm was a 1- to 2-second train of 1-millisecond pulses delivered at a frequency of 30 to 40 Hz and amplitude of 2 to 7 V. Posterior cricoarytenoid stimulation produced a large dynamic abduction (3.5-7 mm) in three patients and moderate abduction (3 mm) in a fourth patient. The fifth patient showed a large but delayed response of 4 mm to stimulation with some lateralization of the vocal fold. In the sixth patient, stimulated abduction was noted on device implantation but was lost postoperatively. All five patients with stimulated abduction postoperatively met the ventilatory criteria for decannulation, and three patients subsequently had decannulation. Long-term stimulation of the posterior cricoarytenoid muscle had no appreciable effect on voice quality. CONCLUSIONS: Electrical stimulation of the posterior cricoarytenoid muscle shows potential as an improved therapy for bilateral vocal fold paralysis.