Hearing Instrument Fitting, Verification, and Follow-Up Care
Fitting targets and verification
Use validated prescriptive targets (e.g., NAL-NL2, DSL v5) matched to the patient's audiogram and preferences. Verify with real-ear measurement (REM): real-ear aided response (REAR), real-ear insertion gain (REIG), and real-ear unaided response (REUR). Probe-tube measurement is the gold standard for verifying gain against targets. Speech mapping confirms audibility across the speech spectrum.
Outcome measures and counseling
Use validated inventories (e.g., COSI, HHIE) to document benefit and guide adjustments. Counseling covers realistic expectations, acclimatization, and communication strategies. Follow-up schedules typically include initial fitting, 2-week, 1-month, and 3-month checks.
Traps
A frequent trap is fitting to manufacturer first-fit rather than verified targets. Another is confusing REIG (insertion gain) with REAR (aided response). Also watch for questions implying REM is optional - best practice requires verification.
Rule of thumb
Target match within ±5 dB across key frequencies is generally acceptable; larger deviations warrant adjustment.