Objective The purpose of this 4-year longitudinal study was to assess the stability of the binaural benefits of head shadow, summation, and squelch for bilateral cochlear implant recipients and to quantify these benefits for the understanding of speech in noise. Design This is a prospective study of 9 patients who received simultaneous bilateral insertion of MED-EL COMBI +40 cochlear implants in a single-stage operation at the University of North Carolina, Chapel Hill, NC. Each patient had postlingual deafness of short duration before insertion of the device. Each year, the patients were tested for word recognition using consonant-nucleus-consonant words in quiet and speech perception in noise using City University of New York sentences. These tests were administered using direct audio input to the implants. Head-related transfer functions were used to simulate speech in noise testing in a spatial environment. Speech was always presented at midline (0), and the noise masker was presented at either side or midline (−90, 0, +90 degrees). Results The binaural benefits of head shadow and summation effects developed early in the postoperative period and remained stable throughout the follow-up period. Squelch developed more slowly and was first demonstrated at 12 months after implantation but continued to increase beyond the first year of follow-up. Conclusion Benefits of head shadow and summation emerge early and remain stable. However, squelch has the most protracted period of development, with increasing benefit after a year or more of implant experience. These data support the idea that binaural integration continues several years after insertion of bilateral cochlear implant devices.

The optimal treatment for bilateral hearing loss continues to evolve as cochlear implant (CI) and hearing aid technologies advance, as does our understanding of the central auditory system. Ongoing discussions continue on the validity and feasibility of bilateral CI in terms of performance, justification of need, medical/surgical safety concerns, and economics. The purpose of this review article is to provide an update on the advantages and disadvantages of bilateral CI and to provide a discussion on timing (simultaneous vs. sequential), technology (bimodal vs. binaural) and feasibility. Binaural advantages are found in both adult and pediatric bilateral CI recipients, the greatest being the head shadow effect and improvements in localization and loudness summation. This theoretically offers an advantage over their unilateral implanted counterparts in terms of improved sound localization and enhanced speech perception under noisy conditions. Most investigators agree that bilateral stimulation during critical periods of development is paramount for optimizing auditory functioning in children. Currently, bilateral CI is widely accepted as a safe and effective means of bilateral auditory stimulation.

Purpose Tumor hypoxia reduces the efficacy of radiation and chemotherapy as well as altering gene expression that promotes cell survival and metastasis. The growth factor receptor, Her2/neu, is overexpressed in 25-30% of breast tumors. Tumors that are Her2 + may have an altered state of oxygenation, relative to Her2 -tumors, due to differences in tumor growth rate and angiogenesis. Methods Her2 blockade was accomplished using an antibody to the receptor (trastuzumab; Herceptin). This study examined the effects of Her2 blockade on tumor angiogenesis, vascular architecture, and hypoxia in Her2 + and Her2 -MCF7 xenograft tumors.Results Treatment with trastuzumab in Her2 + tumors significantly improved tumor oxygenation, increased microvessel density, and improved vascular architecture compared with the control-treated Her2 + tumors. The Her2 + xenografts treated with trastuzumab also demonstrated decreased proliferation indices when compared with control-treated xenografts. These results indicate that Her2 blockade can improve tumor oxygenation by decreasing oxygen consumption (reducing tumor cell proliferation and inducing necrosis) and increasing oxygen delivery (vascular density and architecture). Conclusions These results support the use of trastuzumab as an adjunct in the treatment of breast tumors with chemotherapy or radiotherapy, as improvements in tumor oxygenation should translate into improved treatment response.

Objective To determine the effect of chronic (recurrent) otitis media with effusion (OME) on frequency weighting in the perception of speech in noise. It was hypothesized that children with a history of OME weight speech information in the mid frequency region higher than control children. Design This is a matched cohort study looking at differences in frequency weighting in 12 children with a history of OME 1–2 weeks following placement of tympanostomy tubes compared to 21 control children. Children were tested on their ability to identify key words in sentences presented in speech-shaped noise. The frequency content of the sentences was manipulated in order to determine the relative importance of frequencies in the regions of 1, 2, and 4 kHz. The frequency bands selected were 798–1212 Hz (low band), 1575–2425 Hz (mid band), and 3000–5000 Hz (high band). Initial testing involved adaptive runs where a speech-shaped masker was held at a constant level and the level of the speech with all three bands present varied. Once a level corresponding to 85–90% correct was identified, novel sentences were then presented at this signal-to-noise ratio in fixed block runs, with all bands present, or with one of the three bands omitted. Results The children in the OME group achieved 85–90% correct at a lower signal-to-noise ratio than controls in the adaptive testing, where all three speech bands were present. Fixed block testing indicated that children with OME history gave more weight to speech frequencies in the region of 2000 Hz compared to the age-matched control group. Conclusions The results are consistent with an interpretation that the development of frequency weighting in the perception of speech can be affected by a history of OME.