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Reduced TIM Pattern Variants in Normal Cochlear Implants

Publication Title: Incidence of Trans-Impedance Matrix Pattern Variants in Patients With Normal Anatomy Receiving Cochlear Implantation

Summary

Question
This study examined the incidence of trans-impedance matrix (TIM) heatmap pattern variants in patients with normal cochlear anatomy undergoing cochlear implantation. TIM heatmaps, a tool used to confirm proper placement of the cochlear implant electrode array, were analyzed to understand the prevalence of pattern variants and their potential clinical significance, particularly in primary versus revision surgeries.
Why it Matters
Cochlear implants are critical for restoring hearing in individuals with severe hearing loss, and proper electrode placement is essential for optimal performance. TIM heatmaps provide a non-invasive way to assess electrode positioning, reducing the need for imaging such as X-rays. Understanding the prevalence and implications of TIM pattern variants can help improve surgical practices, minimize complications, and enhance outcomes for patients. This research is particularly relevant for surgeons, audiologists, and patients who depend on cochlear implants for improved hearing and communication.
Methods
The researchers conducted a retrospective review of 321 ears implanted with cochlear devices between June 2020 and June 2024. Patients older than six months with normal cochlear anatomy were included, along with a smaller cohort undergoing revision surgeries. TIM heatmaps were generated during surgery using Cochlear Americas’ Custom Sound 6.0 EP software, and electrode positions were compared to intraoperative X-rays to identify patterns and potential malpositions.
Key Findings
Among the 310 ears implanted in primary surgeries, 86.4% displayed normal TIM heatmaps, while 13.6% showed pattern variants, such as apical heat and basal cooling. In revision surgeries, only 45.5% of heatmaps were normal, suggesting differences in electrode type and microenvironment due to prior implantation. TIM heatmaps were highly sensitive in detecting malpositions like tip foldovers, with one newly identified “double X” pattern in the revision group corresponding to normal electrode placement on X-ray.
Implications
This study confirms that TIM heatmaps are effective for detecting electrode malpositions, reducing reliance on intraoperative X-rays in cases with normal patterns. The higher incidence of pattern variants in revision surgeries highlights potential challenges related to prior implantation. These findings may guide surgeons in improving implantation techniques and inform future development of TIM-based technologies for real-time assessment of electrode placement.
Next Steps
The researchers recommend further studies to explore the causes of TIM pattern variants, such as differences in electrode design, microenvironmental changes, and cochlear anatomy. Controlled experiments, such as cadaveric studies, could provide insights into the clinical relevance of subtle TIM variations and enhance the accuracy of electrode placement assessment.
Funding Information

NYU Langone Hospital and Yale University provided funding and support for this research.

Full Citation

Cottrell J, Schremp C, Winchester A, Friedmann D, Jethanamest D, Spitzer E, Svirsky M, Waltzman S, Shapiro W, McMenomey S, Roland J. Incidence of Trans-Impedance Matrix Pattern Variants in Patients With Normal Anatomy Receiving Cochlear Implantation. Otology & Neurotology 2025, 47: e544-e548. PMID: 41668272, DOI: 10.1097/mao.0000000000004792.
This AI-assisted summary has been reviewed and approved by at least one of the study's authors to ensure it accurately reflects the research.

Authors

  • Justin Cottrell, MD

    First Author
    Yale School of Medicine

    Assistant Professor

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  • J. Thomas Roland

    Last Author
    School Building Streamline Icon: https://streamlinehq.comOther Institution

Other Authors

  • Christine Schremp;
  • Arianna Winchester;
  • David Friedmann;
  • Daniel Jethanamest;
  • Emily Spitzer;
  • Mario Svirsky;
  • Susan B. Waltzman;
  • William H. Shapiro;
  • Sean McMenomey

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