Alan G. Micco

Mismatch negativity in school-age children to speech stimuli that are just perceptibly different ☆

The mismatch negativity event-related potential (MMN) was elicited in normal school-age children in response to just perceptibly different variants of the speech phoneme /da/. A significant MMN was measured in each subject tested. Child and adult MMNs were similar with respect to peak latency and duration. Measures of MMN magnitude (peak-to-peak amplitude and area) were significantly larger in children than in adults. The results of the present study indicate that the MMN can be elicited in response to minimal acoustic stimulus differences in complex speech signals in school-age children. The results support the feasibility of using the MMN as a tool in the study of deficient auditory perception in children.

The mismatch negativity cortical evoked potential elicited by speech in cochlear-implant users

The mismatch negativity (MMN) event-related potential is a non-task related neurophysiologic index of auditory discrimination. The MMN was elicited in eight cochlear implant recipients by the synthesized speech stimulus pair /da/ and /ta/. The response was remarkably similar to the MMN measured in normal-hearing individuals to the same stimuli. The results suggest that the central auditory system can process certain aspects of speech consistently, independent of whether the stimuli are processed through a normal cochlea or mediated by a cochlear prosthesis. The MMN shows promise as a measure for the objective evaluation of cochlear-implant function, and for the study of central neurophysiological processes underlying speech perception.

Clinical Practice Guideline: Bell’s Palsy

Objective Bell’s palsy, named after the Scottish anatomist, Sir Charles Bell, is the most common acute mono-neuropathy, or disorder affecting a single nerve, and is the most common diagnosis associated with facial nerve weakness/paralysis. Bell’s palsy is a rapid unilateral facial nerve paresis (weakness) or paralysis (complete loss of movement) of unknown cause. The condition leads to the partial or complete inability to voluntarily move facial muscles on the affected side of the face. Although typically self-limited, the facial paresis/paralysis that occurs in Bell’s palsy may cause significant temporary oral incompetence and an inability to close the eyelid, leading to potential eye injury. Additional long-term poor outcomes do occur and can be devastating to the patient. Treatments are generally designed to improve facial function and facilitate recovery. There are myriad treatment options for Bell’s palsy, and some controversy exists regarding the effectiveness of several of these options, and there are consequent variations in care. In addition, numerous diagnostic tests available are used in the evaluation of patients with Bell’s palsy. Many of these tests are of questionable benefit in Bell’s palsy. Furthermore, while patients with Bell’s palsy enter the health care system with facial paresis/paralysis as a primary complaint, not all patients with facial paresis/paralysis have Bell’s palsy. It is a concern that patients with alternative underlying etiologies may be misdiagnosed or have unnecessary delay in diagnosis. All of these quality concerns provide an important opportunity for improvement in the diagnosis and management of patients with Bell’s palsy. Purpose The primary purpose of this guideline is to improve the accuracy of diagnosis for Bell’s palsy, to improve the quality of care and outcomes for patients with Bell’s palsy, and to decrease harmful variations in the evaluation and management of Bell’s palsy. This guideline addresses these needs by encouraging accurate and efficient diagnosis and treatment and, when applicable, facilitating patient follow-up to address the management of long-term sequelae or evaluation of new or worsening symptoms not indicative of Bell’s palsy. The guideline is intended for all clinicians in any setting who are likely to diagnose and manage patients with Bell’s palsy. The target population is inclusive of both adults and children presenting with Bell’s palsy. Action Statements The development group made a strong recommendation that (a) clinicians should assess the patient using history and physical examination to exclude identifiable causes of facial paresis or paralysis in patients presenting with acute-onset unilateral facial paresis or paralysis, (b) clinicians should prescribe oral steroids within 72 hours of symptom onset for Bell’s palsy patients 16 years and older, (c) clinicians should not prescribe oral antiviral therapy alone for patients with new-onset Bell’s palsy, and (d) clinicians should implement eye protection for Bell’s palsy patients with impaired eye closure. The panel made recommendations that (a) clinicians should not obtain routine laboratory testing in patients with new-onset Bell’s palsy, (b) clinicians should not routinely perform diagnostic imaging for patients with new-onset Bell’s palsy, (c) clinicians should not perform electrodiagnostic testing in Bell’s palsy patients with incomplete facial paralysis, and (d) clinicians should reassess or refer to a facial nerve specialist those Bell’s palsy patients with (1) new or worsening neurologic findings at any point, (2) ocular symptoms developing at any point, or (3) incomplete facial recovery 3 months after initial symptom onset. The development group provided the following options: (a) clinicians may offer oral antiviral therapy in addition to oral steroids within 72 hours of symptom onset for patients with Bell’s palsy, and (b) clinicians may offer electrodiagnostic testing to Bell’s palsy patients with complete facial paralysis. The development group offered the following no recommendations: (a) no recommendation can be made regarding surgical decompression for patients with Bell’s palsy, (b) no recommendation can be made regarding the effect of acupuncture in patients with Bell’s palsy, and (c) no recommendation can be made regarding the effect of physical therapy in patients with Bell’s palsy.

Clinical Practice Guideline: Bell’s Palsy Executive Summary

The American Academy of Otolaryngology—Head and Neck Surgery Foundation (AAO-HNSF) has published a supplement to this issue featuring the new Clinical Practice Guideline: Bell’s Palsy. To assist in implementing the guideline recommendations, this article summarizes the rationale, purpose, and key action statements. The 11 recommendations developed encourage accurate and efficient diagnosis and treatment and, when applicable, facilitate patient follow-up to address the management of long-term sequelae or evaluation of new or worsening symptoms not indicative of Bell’s palsy. There are myriad treatment options for Bell’s palsy; some controversy exists regarding the effectiveness of several of these options, and there are consequent variations in care. In addition, there are numerous diagnostic tests available that are used in the evaluation of patients with Bell’s palsy. Many of these tests are of questionable benefit in Bell’s palsy. Furthermore, while patients with Bell’s palsy enter the health care system with facial paresis/paralysis as a primary complaint, not all patients with facial paresis/paralysis have Bell’s palsy. It is a concern that patients with alternative underlying etiologies may be misdiagnosed or have an unnecessary delay in diagnosis. All of these quality concerns provide an important opportunity for improvement in the diagnosis and management of patients with Bell’s palsy.

A Within-Subject Comparison of Bimodal Hearing, Bilateral Cochlear Implantation, and Bilateral Cochlear Implantation With Bilateral Hearing Preservation: High-Performing Patients.

Objective To compare speech understanding with bimodal hearing and bilateral cochlear implants (CIs). Study Design Within-subjects, repeated-measures. Methods Speech understanding was assessed in the following conditions: unilateral hearing aid (HA) in the non-implanted ear, unilateral CI, bimodal (CI + HA), and bilateral CI. In addition, three participants had bilateral hearing preservation and were also tested with bilateral CIs and bilateral HAs (BiBi). Setting Tertiary academic CI center. Patients Eight adult sequential bilateral recipients who, despite achieving incredibly high performance with the first CI, self-selected for bilateral cochlear implantation. Intervention(s) Bilateral cochlear implantation. Main Outcome Measure(s) Speech understanding for the adult minimum speech test battery as well as sentences in semidiffuse noise using the R-SPACE system. Results Bilateral CIs afforded significant individual improvement in a complex listening environment even for individuals demonstrating near perfect sentence scores with both the first CI alone as well as the bimodal condition. The 3 BiBi participants demonstrated additional significant benefit over the bilateral CI condition–presumably because of the availability of interaural time difference cues. Conclusions These data suggest that, for noisy environments, adding a second implant can significantly improve speech understanding—even for high-performing unilateral CI with bimodal hearing. In diffuse noise conditions, bilateral acoustic hearing can yield even greater benefits beyond that offered by bilateral implantation.

Neuroendocrine Adenoma of the Middle Ear

Middle ear adenoma is a recently described pathologic entity, first reported by Derlacki and Barney 1 in 1976. Since that time, these tumors have been established as the most common “non-glomus tumors” of the middle ear, but they are still extremely rare occurrences. 2 We add the description of a new case to the literature and note the changing categorization of these tumors.

Electrical resistivity measurements in the mammalian cochlea after neural degeneration.

Objectives/Hypothesis: In the present series of experiments, the effect of neural degeneration on the cochlear structure electrical resistivities was evaluated to test if it alters the current flow in the cochlea and if increased current levels are needed to stimulate the impaired cochlea. In cochlear implants, frequency information is encoded in part by stimulating discrete populations of spiral ganglion cells along the cochlea. However, electrical properties of the cochlear structures result in shunting of the current away from the auditory neurons. This consumes energy, makes cochlear implants less efficient, and drastically reduces battery life. Models of the electrically stimulated cochlea serve to make predictions on current paths using modified and improved cochlear implant electrodes. However, one of the models shortcomings is that most of the values for tissue impedances are not direct measurements. They are derived from bulk impedance measurements, which are fitted to lumped‐element models.

Complicated necrotizing otitis externa

Necrotizing (malignant) otitis externa (NOE) is a rare and invasive infection originating in the external acoustic meatus seen most commonly in diabetes and other immunocompromised states. After a protracted course, disease can smolder and extend into the mastoid, skull base, dural sinuses, and intracranially. We present a case of NOE complicated by mastoiditis, dural sinus thrombosis, and Bezolds abscess in an uncontrolled diabetic presenting with a prolonged course of facial nerve palsy. We stress the importance of maintaining a high index of clinical suspicion for NOE in diabetic patients and offering timely, aggressive treatment to mitigate its complications.

Post-cochlear implant gusher and CSF leak

Abstract Postoperative CSF leak is an uncommon complication after cochlear implantation. The recorded incidence is 0.01%. This chapter discusses CSF leaks and gushers. Preoperative methods to assess the risk of leakage, as well as intraoperative and postoperative methods of repair, are also discussed.

Emerging Technologies in Implantable Auditory Prostheses

Program Description: Current prosthetic auditory implants have achieved a high level of success, however, it would be fair to say that performance gains over the past decade have reached a stable plateau. The latest phase of development has centered primarily on increasing stimulus resolution, preserving residual auditory ultrastructure and function, and implanting higher order neural pathways. To serve these objectives, electrodes have been designed to more closely approximate the spiral ganglion and be inserted virtually atraumatically. Implantation of the higher order pathways has already been performed with combinations of penetrating needles or electrode paddles at the brainstem. Prototypes even exist for stimulation as high up as the auditory cortex. We are now also witnessing the development of highly focused fiberoptic delivery systems for infrared laser energy as the stimulus source. A panel of surgeons and scientists, all of whom have been involved in both clinical and basic science of auditory implants, will debate the strategies being developed to foster the next leap in performance gains. The seminar will begin with a candid appraisal of the successes of currently marketed achievements including modiolar hugging electrodes, hearing preservation hybrid implants, compressed and split arrays for severely malformed and obstructed cochleae, and bilateral implantation. Minimally invasive surgical techniques will be examined with the questions posed: What truly constitutes a minimally invasive procedure? What technical features need to be retained in order to maintain necessary safeguards and precautions? The variable successes of auditory brainstem implantation will be reviewed with an eye toward future improvement. The panelists will then present their collective experience with emerging technologies aiming to push the envelope of performance higher into the future. The constant gains in microprocessor speeds will offer opportunities for development of novel processing strategies including current steering. The emerging concept of integrated drug delivery systems will require a careful re-exploration of the well-known design problems of hermeticity, durability, and ultrastructural trauma induction. Changes in stimulus energy source (eg, infrared laser) will undoubtedly require radical changes in device designs and coding strategies. It is the hope of the organizers that this miniseminar will benefit both the attendees and the panelists through the process of evaluative debate and exploration of new ideas. Educational Objectives: 1) Understand the current status and future direction of hybrid “hearing preservation” cochlear implantation. 2) Understand the newest device and coding strategies including infrared laser optical based devices. 3) Be familiar with the current systems under development including vestibular prostheses, DACS and ABI.