Skull simulator: verification of prescribed force levels in users of percutaneous bone-anchored hearing devices

Author(s)

Gabriela Fireman Martines Dias

• Document type: Master's Dissertation
• Press: Bauru.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB)
• Defense date: 2024-05-03

Examining board members

Maria Fernanda Capoani Garcia Mondelli; Valdéia Vieira de Oliveira

• Advisor: Maria Fernanda Capoani Garcia Mondelli

Abstract

Introduction: Bone Anchored Hearing Devices (BCD) are used in patients with middle and external ear pathologies, since the sound transmitted by these devices to the cochlea is independent of these structures. The percutaneous BCD verification process is carried out using the skull simulator, which traces the force levels, using an internal accelerometer that detects vibrations and converts them into a graphical representation for the verification software, taking into account the prescriptive rule Desired Sensation Level (DSL) - Bone Concution Devices (BC). Objective: To verify the effectiveness of the skull simulator to detect whether the adjustments used in the BCD reach the levels of force prescribed by the DSL-BC rule. For users who obtained results different from those recommended by the rule, the settings were adjusted according to the prescription and a new check was carried out. Furthermore, the results of speech perception tests were compared, in silence and in noise, before and after the BCD adjustments. Method: longitudinal intervention study, which included intra-subject assessment, in two stages: (1) first measurement on coupler (MEASUREMENT 1 M1): strength levels were measured and analyzed whether the participants\' use settings reached the force level values recommended by the DSL-BC rule. (2) second measurement on coupler (MEASUREMENT 2 M2): all devices were reprogrammed, until they were as close to the force level prescribed by the rule. Afterwards, new measurements were carried out with the same objective, until results of up to +- 5dB were obtained. After M1 and M2 and between them, research participants carried out the following assessments: effective gain, Signal to Noise ratio (S/N), recognition of monosyllables and sentences in silence, International Outcome Inventory for Hearing Aids (IOI-HA) and Visual Analogue Scale (VAS). Results: The use of the skull simulator brought a statistically significant difference for the 2kHz frequency at an intensity of 50 dB N, for all frequencies at the medium intensity input (70 dB N) and at the frequencies of 1kHz and 2kHz at an intensity of 90 dB N. Furthermore, there was a statistically significant difference for the Sentence Recognition Threshold in Silence test. Conclusion: The skull simulator proved to be useful for identifying results that differ from those recommended by the prescriptive rule. Therefore, it is an effective device for optimizing strength levels in accordance with the DSL-BC prescriptive rule. However, it can promote improved speech recognition in silence and a similar signal-to-noise ratio in patients using. (AU)

• FAPESP's process: 22/04609-9 - Skull simulator: Verification of prescribed gain in users of percutaneous bone-anchored hearing aids.
• Grantee: Gabriela Fireman Martines Dias
• Support Opportunities: Scholarships in Brazil - Master