PubMed Health⌕ Search

Biomedical subjects

Craig A Buchman

Publications and source records attributed to Craig A Buchman.

At least 19 recordsLinked to original sources
PubMed2006

Auditory neuropathy characteristics in children with cochlear nerve deficiency.

OBJECTIVE: To describe a group of children exhibiting electrophysiologic responses characteristic of auditory neuropathy (AN) who were subsequently identified as having absent or small cochlear nerves (i.e., cochlear nerve deficiency). DESIGN: A retrospective review of the clinical records, audiological testing results, and magnetic resonance imaging (MRI) studies. Fifty-one of 65 children with AN characteristics on auditory brain stem response (ABR) testing had MRI available for review. Nine (18%) of these 51 children with ABR characteristic of AN have been identified as having small (N = 2; 4%) or absent (N = 7; 14%) cochlear nerves on MRI. RESULTS: Of the nine children with cochlear nerve deficiency, five (56%) were affected unilaterally and four (44%) bilaterally. Eight of nine presented after failing a newborn infant hearing screening, whereas one presented at 3 yr of age. On diagnostic ABR testing, all 9 children (9 of 13 affected ears; 69%) had evidence of a cochlear microphonic (CM) and absent neural responses in at least one ear. In the unilateral cases, AN characteristics were detected in all affected ears. In bilateral cases, at least one of the ears in each child demonstrated the AN phenotype, whereas the contralateral ear had no CM identified. Only one ear with cochlear nerve deficiency had present otoacoustic emissions as measured by distortion-product otoacoustic emissions. In children with appropriate available behavioral testing results, all ears without cochlear nerves were identified as having a profound hearing loss. Only 4 (31%) of the 13 ears with cochlear nerve deficiency had a small internal auditory canal on MRI. CONCLUSIONS: Children with cochlear nerve deficiency can present with electrophysiologic evidence of AN. These children frequently refer on newborn screening examinations that use ABR-based testing methods. Similar to other causes of AN, diagnostic ABR testing will show a CM with absent neural responses. Given that 9 (18%) of 51 children with available MRI and electrophysiologic characteristics of AN in our program have been identified as having cochlear nerve deficiency makes this a relatively common diagnosis. These findings suggest that MRI is indicated for all children diagnosed with AN. Moreover, electrophysiologic evidence of unilateral AN in association with a profound hearing loss should make the clinician highly suspicious for this problem. Although children with cochlear nerve deficiency who have a small nerve may benefit from cochlear implantation or amplification, these interventions are obviously contraindicated in children with completely absent cochlear nerves.

Audiometry, Pure-Tone↗
PubMed2006

Internal auditory canal morphology in children with cochlear nerve deficiency.

OBJECTIVE: To describe the internal auditory canal (IAC) and inner ear morphologic characteristics of children with cochlear nerve (CN) deficiency. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Fourteen children with small or absent (deficient) CNs have been identified by means of high-resolution magnetic resonance imaging (MRI). INTERVENTIONS: MRI of the brain. Clinical evaluation. MAIN OUTCOME MEASURES: Review of medical records, audiological testing results, and imaging studies. Images were evaluated for the structure of the cochlear, vestibular and facial nerves, IACs and inner ears. Audiometric thresholds were evaluated in all subjects. METHODS: Fourteen children with small or absent (deficient) CNs have been identified by means of high-resolution MRI. A review of the medical records, audiologic testing results, and imaging studies was undertaken. The images were evaluated for the structure of the cochlear, vestibular and facial nerves, IACs, and inner ears. The audiometric thresholds were evaluated in all subjects. RESULTS: Among the 14 patients, 5 had known syndromes. MRI allowed an exact specification of the nervous structures within all ears with normal-size IACs. Precise characterization of the nerves in ears with small IACs was more difficult, requiring a consideration of both imaging findings and functional parameters. Five children had bilateral deficient CNs, whereas the remaining 9 subjects were affected unilaterally. Thus, 19 ears had CN deficiency (absent CN, 16; small CN, 3). Eleven ears had normal-size IACs and deficient CNs. Of the 9 ears with small IACs, 8 had deficient CNs (absent, 7; small, 1) on the basis of both MRI and functional assessments. Two ears with small IACs had clear morphologic and/or functional evidence for the presence of a CN: one had a small-size CN on MRI, whereas another had a single nerve in a small IAC with present facial and auditory functions. CONCLUSION: The findings of this study suggest that CN deficiency is not an uncommon cause of congenital hearing loss. The findings that most ears with CN deficiency had normal IAC morphology and that two ears with small IACs had CNs present indicate that IAC morphology is an unreliable surrogate marker of CN integrity. On the basis of these findings, we think that high-resolution MRI, rather than CT imaging, should be performed in all cases of pediatric hearing loss, especially in those cases where profound hearing loss has been documented. For ears with small IACs, the resolution of MRI currently remains limiting. In these cases, the determination of CN status frequently requires a variety of anatomic (CT and MRI) and functional tests (auditory brainstem response, otoacoustic emissions, behavioral audiometry, and physical examination).

Audiometry↗
PubMed2006

Monitoring of cochlear function during cochlear implantation.

OBJECTIVE: To report the feasibility of monitoring cochlear function during cochlear implantation. STUDY DESIGN: Case report. SETTING: Tertiary care referral center. METHODS: A child with audiologic features typical of bilateral auditory neuropathy underwent cochlear implantation. The scala tympani was entered inferior and slightly anterior to the round window membrane margin and smooth electrode insertion was achieved. Using single polarity click stimuli, the cochlear microphonic was measured at several steps during surgery. RESULTS: Cochlear microphonics were present at all stages during the implantation process and were clearly distinguished from neural responses by stimulus polarity inversion and constant latencies, despite changes in stimulus level. With the electrode in situ, amplitudes were smaller but persisted until the final measurement at 10 minutes after insertion. At follow-up 2 weeks after surgery, behavioral audiometry results indicated profound hearing loss in the operated ear. CONCLUSIONS: This paper demonstrates the feasibility of monitoring cochlear function during cochlear implantation. The routine surgical approach did not appear to adversely affect the functional measurements. Standard size, full electrode insertion did diminish the amplitude of the cochlear microphonics, possibly as a result of intracochlear mechanical impairment. Ultimately, profound hearing loss was documented, indicating that factors other than immediate changes induced by electrode insertion were likely responsible for the loss of cochlear function.

Cochlear Implantation↗
PubMed2005

The accuracy of computer-aided surgery in neurotologic approaches to the temporal bone: a cadaver study.

OBJECTIVE: To assess the accuracy of computer-aided surgery for common neurotologic approaches to the temporal bone. STUDY DESIGN AND SETTING: Cadaveric heads were dissected by using standard neurotologic approaches to the temporal bone including translabyrinthine, middle fossa, and retrosigmoid. Dissected anatomic landmarks from each approach were compared with CT images that were obtained before dissection on the VectorVision 2 system (BrainLAB Corp, Munich, Germany) and the variability measured from digital images. Each approach was performed 5 times, with each anatomic landmark measured 3 times from each approach. RESULTS: The accuracy of the computer-aided surgery system was less than 1 mm for all anatomic points measured. Forty-two of the 49 measured points were accurate to less than 0.5 mm. CONCLUSIONS: Computer-aided surgery of the temporal bone using common neurotologic approaches can be performed accurately and reliably in cadaver specimens. SIGNIFICANCE: The utility and limitations of computer-aided surgery in the temporal bone are discussed. EBM RATING: B-2.

Cadaver↗
PubMed2005

Cytokine amplification by respiratory syncytial virus infection in human nasal epithelial cells.

OBJECTIVES: Respiratory syncytial virus (RSV) is an important cause of upper respiratory infections and is known to play a causal role in the pathogenesis of rhinitis, sinusitis, acute otitis media, and pneumonia. RSV appears to prime the respiratory tract to secondary inciting events, such as bacterial or antigen challenges. To study the proinflammatory priming effects of RSV infection, cytokine expression was measured in well-differentiated human nasal epithelial cells (WD-NE) after RSV infection alone or after subsequent tumor necrosis factor (TNF)-alpha stimulation. STUDY DESIGN: In vitro investigation. METHODS: Human nasal epithelial cells were obtained from surgical specimens and allowed to differentiate in air-liquid interface cultures until ciliation and mucus production were evident. Two experimental paradigms were used. First, accumulation of cytokines in the media was measured by real-time, quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay after RSV infection alone. In the second set of experiments, cytokines were also measured after TNF-alpha stimulation in both RSV-infected and uninfected cultures. RESULTS: RSV infection of WD-NE resulted in significant accumulations of interleukin (IL)-6, IL-8, and RANTES when compared with findings in control samples. Real-time, quantitative RT-PCR demonstrated significant increases in IL-8 gene expression following RSV infection when compared to controls. Secondary TNF-alpha stimulation following well-established (i.e., 72 h) RSV infection induced marked increases in IL-6, IL-8, and RANTES when compared with both RSV infection alone and TNF-alpha stimulation alone. CONCLUSIONS: These findings suggest that RSV infection primes nasal epithelial cells to secondary proinflammatory challenge, resulting in a hyperimmune response. RSV-induced priming of a hyperimmune response may be important in the pathogenesis of sinusitis, acute otitis media, and pneumonia.

Chemokine CCL5↗
PubMed2005

MED-EL Combi40+ cochlear implantation in adults.

OBJECTIVE/HYPOTHESIS: Cochlear implantation is currently the treatment of choice for severe to profound sensorineural hearing loss. The MED-EL Combi40+ (Innsbruck, Austria) cochlear implant system was approved for use in the United States in 2001. This device employs a 31-mm-long electrode array, ceramic case, and continuous interleaved sampling with Hilbert transformation for envelope extraction. A single institution's experience with the Combi40+ implant in adult patients was reviewed. STUDY DESIGN: Retrospective chart review. METHODS: Medical-surgical and audiological data were collected from 112 patients who received a MED-EL Combi40+ cochlear implant between December 1998 and April 2004. RESULTS: The rate of surgical complications and speech perception testing results compared favorably with those of other cochlear implant systems. For postlingually deafened adults, mean CNC word, HINTQ, CUNY, and HINT + 10 dB signal-to-noise ratio scores after 1 year of implant usage were 54%, 87%, 96%, and 64%, respectively. Prelingually deafened adults also derived significant benefit, but plateau performance for these patients was well below that for patients with later onset of deafness and significant variability was seen in this group. Repeat implantation for suspected device malfunction was undertaken in seven cases (6% of devices) (mean duration of use, 28 +/- 12 mo) with ultimate resolution of the presenting problem. CONCLUSION: The study results support the safety and efficacy of cochlear implantation with the MED-EL Combi40+ cochlear implant system.

Adolescent↗
PubMed2005

Bilateral cochlear implantation: current concepts.

PURPOSE OF REVIEW: Recent experience has shown an advantage of bilateral cochlear implantation over unilateral implantation. These documented benefits include improved speech perception in noisy environments and improved sound localization. Recently, investigators have studied the long-term benefit, evaluation of neural integration, programming, vestibular effects, and complications of bilateral cochlear implantation. This article summarizes the current research endeavors to improve our understanding and utilization of bilateral cochlear implantation. RECENT FINDINGS: Numerous positive benefits of bilateral cochlear implantation have been confirmed. Patients receive significant head shadow benefit from bilateral implantation, and obtain nominal benefits from summation and squelch effects. Sound localization benefits have been confirmed. Speech perception in noise with bilateral implantation is significantly better than unilateral implantation and continues to improve 24 months after implantation. Areas for further improvement have also been identified. Despite technological improvements in speech processing strategies, measured intraaural time differences in bilateral cochlear implant recipients remain considerably greater than those with normal hearing. Programming challenges persist to optimize sound processing with bilateral implants. Vestibular effects of bilateral cochlear implantation appear safe but need further study. Important considerations including the duration of implant function, long-term complication rate, and improvements in implant technology will continue to strongly influence the role of bilateral cochlear implantation. SUMMARY: Bilateral cochlear implantation provides advantages over unilateral implantation including improved speech perception in noise and improved sound localization. Further research is needed to define the optimal indications and to maximize the benefit of bilateral implantation.

Cochlear Implantation↗
PubMed2004

Cochlear implantation in children with congenital inner ear malformations.

OBJECTIVE/HYPOTHESIS: To assess the audiologic and surgical outcomes for pediatric cochlear implant patients with inner ear malformations. STUDY DESIGN: Retrospective review of 315 pediatric cochlear implant cases from 1994 to 2002. METHODS: Twenty-eight pediatric cochlear implant patients with known inner ear malformations determined on high-resolution computed tomography (HRCT) of the temporal bone were the subjects of review. Results of HRCT findings, intraoperative findings, postoperative complications, and objective measures of both closed- and open-set testing of speech perception were analyzed. RESULTS: Patients with the constellation of an incompletely partitioned (IP) cochlea, enlarged vestibular aqueduct (EVA), and a dilated vestibule (i.e., Mondini's malformation) as well as those with an isolated EVA or partial semicircular canal aplasia have relatively good levels of speech perception. Patients with total semicircular canal aplasia, isolated IP, cochlear hypoplasia, or common cavity demonstrated lower levels of performance. Poor performance may be related to associated developmental delays rather than labyrinthine anatomy alone. Complications of surgery were relatively limited. CONCLUSIONS: Cochlear implantation can be successfully performed in children with inner ear malformations. These children and their parents can expect significant auditory benefits from this intervention. The various types of inner ear malformations may have quite different prognoses for good auditory performance.

Adolescent↗
PubMed2004

Cochlear implantation for children with GJB2-related deafness.

OBJECTIVES/HYPOTHESIS: Mutations in GJB2 are a common cause of congenital sensorineural hearing loss. Many children with these mutations receive cochlear implants for auditory habilitation. The purpose of the study was to compare the speech perception performance of cochlear implant patients with GJB2-related deafness to patients without GJB2-related deafness. STUDY DESIGN: Retrospective case review. METHODS: Pediatric cochlear implant recipients who have been tested for GJB2 mutation underwent chart review. All patients received cochlear implantation at a tertiary referral center, followed by outpatient auditory habilitation. Charts were reviewed for cause and duration of deafness, age at time of cochlear implantation, intraoperative and postoperative complications, duration of use, and current age. Results of standard tests of speech perception administered as a part of the patients' auditory habilitation were reviewed. RESULTS: Twenty patients with GJB2 mutations were compared with 27 patients without GJB2 mutations. There was no statistical difference between patients with and without GJB2-related congenital sensorineural hearing loss with regard to open-set and closed-set speech recognition performance at 12, 24, and 36 months after cochlear implantation. Surgical complications were uncommon. CONCLUSION: Pediatric patients with congenital sensorineural hearing loss without other comorbid conditions (eg, developmental delay, inner ear malformations) perform well when they receive cochlear implantation and auditory habilitation. The presence or absence of GJB2 mutation does not appear to impact speech recognition performance at 12, 24, and 36 months after implantation.

Child, Preschool↗
PubMed2004

Vestibular effects of cochlear implantation.

OBJECTIVES/HYPOTHESIS: Cochlear implantation (CI) carries with it the potential risk for vestibular system insult or stimulation with resultant dysfunction. As candidate profiles continue to evolve and with the recent development of bilateral CI, understanding the significance of this risk takes on an increasing importance. STUDY DESIGN: Between 1997 to 2001, a prospective observational study was carried out in a tertiary care medical center to assess the effects of unilateral CI on the vestibular system. METHODS: Assessment was performed using the dizziness handicap inventory (DHI), vestibulo-ocular reflex (VOR) testing using both alternate bithermal caloric irrigations (ENG) and rotational chair-generated sinusoidal harmonic accelerations (SHA), and computerized dynamic platform posturography (CDP) at preoperative, 1-month, 4-month, 1-year and 2-year postimplantation visits. CI was carried out without respect to the preoperative vestibular function test results. RESULTS: Specifically, 86 patients were entered into the study after informed consent. For the group as a whole, pair wise comparisons revealed few significant differences between preoperative and postoperative values for VOR testing (ENG and SHA) at any of the follow-up intervals. Likewise, DHI testing was also unchanged except for significant reductions (improvements) in the emotional subcategory scores at both the 4-month and 1-year intervals. CDP results demonstrated substantial improvements in postural sway in the vestibular conditions (5 and 6) as well as composite scores with the device "off" and "on" at the 1-month, 4-month, 1-year, and 2-year intervals. Device activation appeared to improve postural stability in some conditions. Excluding those patients with preoperative areflexic or hyporeflexic responses in the implanted ear (total [warm + cool] caloric response or=21 deg/s maximum slow phase velocity) in total caloric response were observed for 8 (29%) patients at the 4-month interval. These persisted throughout the study period. These changes were accompanied by significant low frequency phase changes on SHA testing confirming a VOR insult. Of interest, no significant changes were detected in the DHI or CDP, and there were no effects of age, sex, device manufacturer, or etiology of hearing loss (HL) for these patients. CONCLUSIONS: Unilateral CI rarely results in significant adverse effects on the vestibular system as measured by the DHI, ENG, SHA, and CDP. On the contrary, patients that underwent CI experienced significant improvements in the objective measures of postural stability as measured by CDP. Device activation in music appeared to have an additional positive effect on postural stability during CDP testing. Although VOR testing demonstrated some decreases in response, patients did not suffer from disabling vestibular effects following CI. The mechanism underlying these findings remains speculative. These findings should be considered in counseling patients about CI.

Adolescent↗
PubMed2004

Prospective evaluation of intraoperative cochlear implant radiographs.

OBJECTIVE: To investigate the clinical utility of intraoperative plain radiographs in cochlear implant surgery. STUDY DESIGN: Prospective. SETTING: Tertiary referral center. PATIENTS: Eighty consecutive adult and pediatric cochlear implant operations at a facility capable of intraoperative radiographs were evaluated over 12 months. INTERVENTIONS: Intraoperative plain radiographs to assess implant location and surgeon questionnaire. MAIN OUTCOME MEASURES: Plain radiographic image interpretation and surgeon questionnaire. RESULTS: In one revision surgery, the intraoperative plain radiograph was useful for confirming the cochleostomy site. In the remaining 79 operations, no changes in the electrode arrays were made on the basis of the information provided by intra-operative plain radiographs. CONCLUSIONS: In this cohort, intraoperative plain radiographs were not useful for uncomplicated implant operations; however, they may be useful for complicated operations. These results may have implications for surgical cost and patient radiation exposure.

Adult↗
PubMed2004

Revision cochlear implant surgery in adult patients with suspected device malfunction.

OBJECTIVE: To report the outcomes of patients that have undergone revision cochlear implant surgery for suspected device malfunction. STUDY DESIGN: Retrospective case series. SETTING: Academic medical center. PATIENTS: Adult cochlear implant patients with devices that fail to lock or maintain a lock but are associated with troubling signs and symptoms. INTERVENTION: Revision cochlear implant surgery. MAIN OUTCOME MEASURES: Demographics, presenting signs and symptoms, surgical findings, complications, audiologic performance and device analysis. RESULTS: To date, 33 revision cochlear implant operations have been performed in 30 patients. Eight (24%) presented with a failure of the speech processor to lock with the internal device (i.e., hard failure). Twenty-five (76%) presented with either aversive auditory (n = 23 [92%]) or nonauditory (n = 21 [84%]) symptoms or performance-related issues (n = 16 [64%]) while maintaining a lock (i.e., suspected soft failure). Revision surgery resulted in resolution of the patient's presenting signs and symptoms in nearly 90% of cases and significant improvements in auditory performance. Perioperative complications were uncommon. Preoperative testing and device analysis frequently did not reveal the reason for presumed device malfunction. CONCLUSION: Revision cochlear implantation should be considered in patients significantly affected by intolerable auditory and/or nonauditory symptoms or when performance issues have been documented.

Analysis of Variance↗
PubMed2004

Cochlear implantation in patients with substantial residual hearing.

OBJECTIVES: Cochlear implantation is an effective means for providing auditory rehabilitation in adult patients with severe to profound sensorineural hearing loss. It has been hypothesized that patients with substantial, preoperative residual hearing would be excellent cochlear implant candidates because of surviving neural populations and a lack of auditory deprivation. The purpose of this study is to describe the outcomes of patients with substantial residual hearing who have undergone cochlear implantation. STUDY DESIGN: Retrospective chart review of patients with substantial preoperative residual hearing who underwent cochlear implantation. METHODS: Chart reviews were completed for patients with substantial residual hearing who underwent cochlear implantation (City University of New York Sentence Test [CUNY] > 60%, Hearing in Noise Test sentences presented in quiet [HINTQ] > 50%, or Consonant-Nucleus-Consonant [CNC] > 20% in the ear to be implanted). Preoperative and postoperative measures of audiologic performance as well as complications were assessed. RESULTS: All 12 patients who met inclusion criteria ultimately surpassed their preoperative aided performance level after implantation and gained significant benefit from their cochlear implant. At 6 months postimplantation, mean CUNY, HINTQ, and CNC scores were 93%, 78%, and 48% in the implant ear alone, respectively. However, progress was slower than expected for many patients, and at least one patient took 1 year to surpass his preoperative performance level. There were no complications from surgery in this selected group of patients. CONCLUSIONS: Patients with some degree of residual hearing do benefit from cochlear implantation. However, there may be an initial decline in performance as compared with preoperative levels. This decline is overcome in time in this patient population. These patients need to be counseled accordingly.

Age Factors↗
PubMed2003

Pediatric tympanoplasty: effect of contralateral ear status on outcomes.

OBJECTIVE: To assess the prognostic value of different variables on the outcome of pediatric type I tympanoplasty. DESIGN: Retrospective review of medical records. SETTING: An otolaryngology department in a large urban tertiary care medical center. PATIENTS: We reviewed 72 ears in 60 patients who had undergone a type I tympanoplasty from 1987 to 2000. Patient ages ranged from 3 to 18 years. INTERVENTIONS: Type I tympanoplasty. MAIN OUTCOME MEASURES: We identified the following 3 criteria for success: (1) healing of the neotympanic graft; (2) healing of the graft with a postoperative air-bone gap of no greater than 20 dB; and (3) healing of the graft with aeration of the middle ear space. RESULTS: Healing occurred in 59 (82%) of the 72 neotympanic grafts; 39 (83%) of the 47 healed ears for which a postoperative audiogram was available had an air-bone gap of no greater than 20 dB; and 49 (83%) of the 59 healed ears had a normally aerated middle ear space. A statistically significant difference in the rate of graft healing was identified for large perforations (76%), as well as for creation of an aerated middle ear space, when there was evidence of ongoing contralateral eustachian tube dysfunction (ie, otitis media with effusion or negative middle ear pressure, but not a perforation). CONCLUSIONS: Pediatric type I tympanoplasty can offer reasonably good chances for postoperative graft healing, serviceable hearing, and creation of an air-containing middle ear space if performed in carefully selected patients. Caution should be exercised in performing tympanoplasty in children with evidence of ongoing eustachian tube dysfunction, as evidenced by otitis media with effusion and negative middle ear pressure, but not perforations, in the contralateral ear.

Adolescent↗
PubMed2003

Viral otitis media.

Acute otitis media (AOM) and viral upper respiratory tract infections (URIs) represent the two most common diseases affecting the human population, and account for substantial patient morbidity and health care costs. Epidemiologic and experimental studies suggest that URIs play a causal role in the pathogenesis of AOM. Specifically, viruses can either invade the middle ear (ME) space and invoke an inflammatory response that culminates in ME effusion formation and consequent symptoms, or URIs might cause eustachian-tube dysfunction, resulting in negative ME pressures and subsequent ME effusion (hydrops ex vacuo theory). The events responsible for the inflammatory response of the human ME following viral exposure have not been well characterized. Although many prophylactic and therapeutic interventions have been evaluated for the treatment of AOM, the information on virus-specific interventions is sparse. In this article, the epidemiology, pathogenesis, diagnosis, and management of viral otitis media are reviewed.

Humans↗