CASE STUDY (CARR0928)
This 86 year old female patient was seen for post-dispensing visit one week after the initial fitting of a CLASS II canal hearing instrument to the right ear. A new wearer, the patient presented with a complaint of insecure fit in the ear and acoustic feedback. Figure A (inline image below, 20k) shows that, despite an initial orientation to hearing aid insertion and operation at time of dispensing, the patient was rotating the hearing aid 90 degrees off axis, creating both problems.
Video Oto-Macroscopy (VOM) was used to illustrate dynamically both the correct (Figure B inline image; 20k) and incorrect insertion orientations
In the correct orientation, the patient reported an inability to easily adjust the hearing aid gain control (GC), (Figure C inline image; 14k) previously modified at time of fitting to a double height gain wheel (2W). VOM was used to help the patient locate and manipulate the gain control.
To refine further the gain control operation, a cap 2W gain wheel was installed (Figure D, inline image; 22k) to allow easy adjustment of volume with a two-fingered "watch-winding" motion. At the next post-fitting visit, the patient demonstrated a consistent ability to insert the aid correctly and adjust the gain control with no acoustic feedback or extrusion.
After an additional two weeks, the patient reverted to her previous difficulty with volume control adjustment and a newly developed functional problem with 312 battery insertion. At this time, a decision was made to refit the patient with a CLASS II half-concha instrument having a larger 2W, placed in a higher position on the faceplate, and a 13 battery. (Figure E, inline image; 19k) After a training session using VO for visual feedback, the patient demonstrated a promising facility with insertion, VC adjustment and (13) battery replacement.