During a trial period with CIC amplification, it is helpful to orient patients to the location and operation of the set-screw volume control adjustment (SVC). Close proximity of the vent, microphone and SVC often leads to the inadvertent injection of a cleaning tool or miniature screwdriver into the incorrect orifice.
Video Otoscopy (VO) is used to assist the patient in locating and differentiating among the CIC microphone, vent and SVC. The Sullivan VOE stand serves as a "third hand", supporting the VOE head while the CIC aid is held with one hand and SVC adjustment demonstrated with the other. The patient is shown the SVC location with VO and with a magnifying glass. The latter is included in all dispensing kits to allow carry-through on VO hygiene and SVC operation training.
The rotational range of SVC operation is defined in terms of hour hand settings on a clock face with 12:00 at the top in the standard insertion position. In the inline illustration above, the minimum SVC setting is located, relative to in situ faceplate orientation, at 3:00 while the maximum is found at 10:30. The actual clock hour min/max positions may vary between instruments and among laboratories. It is practical to specify a fundamental CIC response matrix which will ultimately allow a range of SVC adjustment both above and below the ultimately Preferred Listening Level (PLL).
Manual dexterity limitations may preclude application of this orientation technique in every case. During the first week or two of the hearing aid trial period, if patients perceive the initial respose as either too high or too low, they are encouraged to alter the SVC setting, noting the original and new SVC position in terms of the clock hour-hand orientation, .
The value of this patient empowerment in the fitting and orientation process offsets any service visit inconveniences caused by misapplication of the miniature screwdriver to the CIC faceplate.