Spectral compensation

Spectral Compensation:

Different selection options provide the ability to alter the speech signal (Figure 195).

Linear Curve	No Correction
DSL i/o Correction	DSL i/o Target Corrections
MCL from TA	MCL Tone Audiogram Corrections
MCL of the AHA	MCL of the AHA (Loudness Scaling) Corrections
Hearing Level	Hearing Threshold Corrections
Hearing Level 1/2 Correction	Hearing Level 1/2 Corrections
Hearing Level 1/3 Correction	Hearing Level 1/3 Corrections
Hearing Level DSL i/o Simulation	DSL i/o Hearing Loss Simulation
Hearing Level MCL of TA Simulation	MCL Tone Audiogram Curve Hearing Loss Simulation
Hearing Level MCL of AHA Simulation	MCL of the AHA (Loudness Scaling) Hearing Loss Simulation
Hearing Level Simulation	Hearing Level Hearing Loss Simulation
Hearing Level Simulation (HV 1/2)"	Hearing Level 1/2 Method Hearing Loss Simulation
Hearing Level Simulation (HV 1/3)"	Hearing Level 1/3 Method Hearing Loss Simulation

Figure 195: List of options for spectral compensation changes.

The spectral compensation is divided into two groups:

Discrimination improvement correction
The hearing loss simulation

The ACAM System is able to calculate filter curves based on the saved audiograms (Figures 196 and 197). If applicable, the filter curves can be enabled and used to distort the frequency response of the playback material.

Figure 196: Tone audiogram from ACAM

Figure 197: Calculated filter curves (Calculation based on the hearing threshold)

The figure above shows a tone audiogram on the left (Figure 196). A filter curve that was calculated based on the tone audiogram is shown on the right (Figure 197). The thresholds (red) and the spectral compensation (orange) were used to create a hearing loss simulation.

The hearing instrument fitting performs measurements with and without hearing aids in the soundfield. It is best not to apply the spectral compensation option in this scenario because undistorted speech is preferred for this type of measurement.

It is possible to play a simulation of hearing loss for family members of the patient.

Enable the spectral compensation with the adjustment: HL simulation (hearing loss). A filter curve will be calculated based on the thresholds that are saved in the system.
For example a high frequency hearing loss results in difficulty with speech discrimination for a person with hearing loss in comparison to a normal hearing individual. When the spectral compensation is enabled, level adjustment needs to be re-calibrated. The greater the high frequency hearing loss the more volume you will have to provide through the loudness control.