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Biomedical subjects

D Shipp

Publications and source records attributed to D Shipp.

7 recordsLinked to original sources
PubMed2005

Cochlear implantation in cochlear otosclerosis.

OBJECTIVES/HYPOTHESIS: The objective was to correlate implant performance in cochlear otosclerosis to 1) matched control samples, 2) severity of otic capsule involvement, 3) prior ipsilateral surgery, and 4) programming issues. STUDY DESIGN: Retrospective case controlled study. METHODS: Study cohort comprised 30 individuals. Diagnosis was based on prior ear surgery (stapedectomy [n = 18] or fenestration [n = 2]) and/or pathognomonic radiological findings. High-resolution computed tomography images of the temporal bones were assessed by two radiologists and graded (range, 0-3) for the extent of otosclerosis. Operative records were reviewed. Performance, programming visits, and the number of electrode deactivations at 6 months and at 1 year after implantation were determined for the individuals with otosclerosis and compared with a group of matched control subjects. A within-group comparison correlating severity of otosclerosis to the above was carried out. RESULTS: Implant performance in individuals with cochlear otosclerosis was not significantly different from those without. Previous surgery on the side of implantation did not alter performance. Programming difficulty as reflected in the number of visits and electrode deactivation for sound quality reasons were comparable. Deactivation for facial nerve stimulation occurred exclusively in otosclerotics with the most severe radiological disease (grade 3) and was only with non-modiolar hugging electrodes (n = 5). There was no observed difference between the radiological extent of otosclerosis and implant performance. CONCLUSION: Individuals with severe otosclerosis considering cochlear implantation can be counseled to expect similar benefit to those without, regardless of whether prior surgery occurred on the side of implantation or of severity of otic capsule involvement. There is a significant risk of facial nerve stimulation in otosclerotics with grade 3 disease.

Case-Control Studies↗
PubMed2001

Does choosing the "worse" ear for cochlear implantation affect outcome?

OBJECTIVE: To determine whether choosing the "better" ear or the "worse" ear for cochlear implantation impacts performance outcome. DESIGN: Retrospective cohort study. SETTING: University teaching hospital-cochlear implant program. METHODS: Two groups of cochlear implantees were selected and matched based on clinical parameters, including duration of deafness/age at implantation, implant types, and processing strategies. Nineteen patients received an implant in his or her "better" ear of the two that had been amplified. An equal number of patients received an implant in the "worse" ear--an ear that was not amplified or was chosen to avoid causing oscillopsia; or if the patient was not willing to relinquish his or her hearing aid in the "better" ear based on subjective or objective criteria. Standard speech perception testing was performed. RESULTS: The average open-set speech perception responses at 1 year after implantation were as follows: word recognition score 40.4% and sentence recognition score 81% in the aided subjects (better ears); word recognition score 41.5% and sentence recognition score 84.5% in the unaided group (worse ears). CONCLUSION: No differences were found between the two groups of implantees. Choosing the "worse" ear for implantation did not appear to have a negative impact on performance outcome in this match-paired study.

Adolescent↗
PubMed1999

Depth and quality of electrode insertion: a radiologic and pitch scaling assessment of two cochlear implant systems.

OBJECTIVE: To compare the depth of electrode insertion in two types of cochlear implants, and to assess the ability of the implantees in each group to place-pitch during random electrical stimulation. STUDY DESIGN: This was a prospective clinical study. SETTING: This study was performed at an implant program within a university teaching hospital. PATIENTS: Five consecutive patients with the Clarion (Advanced Bionics, Symlar, CA, U.S.A.) device and 5 with the Nucleus-22 (Cochlear Corporation, Sydney, Australia) implants were enrolled. All 10 implantees had fully active and functioning electrodes. INTERVENTIONS: The depth of insertion was determined using plain anteroposterior skull film and high resolution computed tomography (CT). The quality of electrode insertion was assessed by pitch scaling; electrodes were randomly stimulated to generate subjective pitch responses. OUTCOME MEASURES: The depth of electrode insertion was measured radiographically as degrees of angular rotation within the cochlea. For pitch scaling, the averaged responses to electrical stimulation was plotted against the "place" of the electrodes along the array. Pitch range, plateauing, and reversal of pitches were also noted. Insertion depth was correlated with the result of pitch scaling and open-set speech discrimination at 3 months. RESULTS: The mean insertion depth was 406 degrees for the Clarion device and 254 degrees for the Nucleus device. CT was used to confirm the intracochlear placement of the electrodes and their relationships to the cochleostomy site. It did not confer more information than the plain films unless kinking had occurred. Pitch perception was consistent with the tonotopic organization of the cochlea. The Nucleus-22 recipients displayed a broader range of pitches with less plateaus and reversals than the Clarion implants. The depth of insertion did not compare well with the outcome of pitch scaling or with open-set speech discrimination scores in either group of implantees. CONCLUSION: The preformed spiral array of the Clarion device allowed deeper electrode insertion compared to the Nucleus-22 device. However, depth of insertion did not translate into better pitch placement.

Adult↗
PubMedDate not supplied

Factors affecting auditory performance of postlinguistically deaf adults using cochlear implants.

A model of auditory performance and a model of ganglion cell survival in postlinguistically deafened adult cochlear implant users are suggested to describe the effects of aetiology, duration of deafness, age at implantation, age at onset of deafness, and duration of implant use. The models were compared with published data and a composite data set including 808 implant users. Qualitative agreement with the model of auditory performance was found. Duration of deafness had a strong negative effect on performance. Age at implantation had a slight negative effect on performance, increasing after age 60 years. Age at onset of deafness had little effect on performance up to age 60. Duration of implant use had a positive effect on performance. Aetiology had a relatively weak effect on performance.

Adolescent↗
PubMedDate not supplied

[Interaction of proflavin with deoxytetraribonucleoside triphosphate 5'-d(ApGpCpT): thermodynamic analysis from (1)H NMR data].

Temperature relationships of chemical shifts of protons of proflavin mixed with deoxytetraribonucleoside triphosphate 5'-d(ApGpCpT) in water solution were investigated on impulse NMR spectrometer (500 MHz). Procedure is suggested for calculating values of mole fractions of various associates in solution as a function against temperature. Free energies of Gibbs, entalpy and entropy were determined in the reactions of complex formation 1:1, 1:2, 2:1 of proflavin with tetranucleotide. The results point to a significant role of hydrophobic interactions during the formation of dye--tetramere duplex complexes.

Magnetic Resonance Spectroscopy↗