🎧 HearingAid Pro

📋 Executive Summary

Primary Indications

🔬 Clinical Features

1. Audiometric Frequency Control (8-Band Parametric EQ)

The application provides frequency-specific amplification at standard audiometric test frequencies with independent gain control:

2. Evidence-Based Prescription Formulas

The application implements two internationally recognized hearing aid fitting formulas:

3. Independent Binaural Amplification (Stereo Processing)

The application automatically detects output device type and applies appropriate processing:

4. Pure-Tone Audiometry Test (In-App)

Test Protocol:

• Method: Modified Hughson-Westlake procedure (ascending threshold search)
• Frequencies Tested: 250, 500, 1000, 2000, 4000, 8000 Hz (6 frequencies per ear)
• Test Order: 1 kHz → 2 kHz → 4 kHz → 8 kHz → 500 Hz → 250 Hz (standard clinical sequence)
• Starting Level: 40 dB HL
• Step Size: 5 dB decrements after positive response, 10 dB increments after no response
• Threshold Criterion: Last level at which patient responded
• Test Duration: 4-8 minutes (both ears), 2-4 minutes (single ear)
• Requirements: Stereo headphones (mandatory), quiet environment (recommended <40 dBA)

5. Adaptive Feedback Cancellation

Technology: FFT-based spectral analysis with narrow-band notch filtering

Algorithm:

1. Detection Phase: 3-second continuous audio analysis using 4096-point FFT with Hanning window
2. Peak Identification: Detects frequencies with magnitudes within 15 dB of maximum in 500-8000 Hz range
3. Validation: Cross-validates peaks across 20 consecutive audio buffers to avoid false positives
4. Cancellation: Applies parametric notch filters (0.3 octave bandwidth, -35 dB attenuation) at detected feedback frequencies

6. Manual Audiogram Entry

Audiologists can manually enter threshold data from clinical audiometry:

• Data Input: Hearing thresholds in dB HL for 8 frequencies per ear
• Chart Visualization: Standard audiogram format (frequency vs. threshold)
• Classification: Automatic degree-of-loss calculation (normal/slight/mild/moderate/moderately-severe/severe/profound)
• Storage: Unlimited audiogram storage with date tracking
• Notes Field: Clinical notes, test conditions, conductive components, etc.

7. Tinnitus Retraining Therapy (TRT)

Comprehensive tinnitus management through sound therapy and habituation protocols:

Sound Therapy Options:

• White Noise: Broadband noise for complete masking
• Pink Noise: Equal energy per octave, natural sound quality
• Brown Noise: Deep, relaxing low-frequency emphasis
• Nature Sounds: Ocean waves, rainfall, forest ambience
• Tinnitus Matching: Custom tone generation to match perceived tinnitus frequency

Therapy Protocols:

• Complete Masking: Sound level above tinnitus perception threshold (not recommended for long-term use)
• Partial Masking: Sound level at or slightly below tinnitus level (preferred for habituation)
• Mixing Point: Background sound barely audible with tinnitus (optimal for TRT)
• Per-Ear Therapy: Independent sound therapy for each ear based on tinnitus laterality

Clinical Application:

1. Assessment: Determine tinnitus frequency, loudness, and laterality (left/right/bilateral)
2. Sound Selection: Choose appropriate therapeutic sound (typically pink/white noise or nature sounds)
3. Level Setting: Start at mixing point (barely audible), patient can adjust as needed
4. Counseling: Educate patient on habituation process (typically 12-24 months)
5. Combination Therapy: Can be used simultaneously with hearing aid amplification for optimal results

⚙️ Technical Specifications

Audio Processing Chain

Input (Microphone, 2 channels)
    ├─► LEFT CHANNEL PROCESSING:
    │   ├─ 250 Hz Parametric EQ (gain per left audiogram)
    │   ├─ 500 Hz Parametric EQ
    │   ├─ 1 kHz Parametric EQ
    │   ├─ 2 kHz Parametric EQ
    │   ├─ 3 kHz Parametric EQ
    │   ├─ 4 kHz Parametric EQ
    │   ├─ 6 kHz Parametric EQ
    │   ├─ 8 kHz Parametric EQ
    │   └─► Left Channel Output
    │
    └─► RIGHT CHANNEL PROCESSING:
        ├─ 250 Hz Parametric EQ (gain per right audiogram)
        ├─ 500 Hz Parametric EQ
        ├─ 1 kHz Parametric EQ
        ├─ 2 kHz Parametric EQ
        ├─ 3 kHz Parametric EQ
        ├─ 4 kHz Parametric EQ
        ├─ 6 kHz Parametric EQ
        ├─ 8 kHz Parametric EQ
        └─► Right Channel Output
                    ↓
        Overall Gain Control → Main Mixer → Output
                    

🎚️ Acoustic Environments & Presets

Pre-configured frequency response curves for common listening situations:

Tinnitus Therapy Sounds

📱 Device Compatibility & Optimization

Recommended Audio Hardware

AirPods Optimization Features

System Requirements

• iOS Version: 14.0 or later
• Devices: iPhone, iPad
• Storage: <10 MB
• Audio Hardware: Stereo headphones/earphones strongly recommended for optimal performance

👨‍⚕️ Clinical Workflow & Patient Fitting

Initial Fitting Protocol

1. Audiogram Acquisition
   • Preferred: Manual entry from clinical audiometry (most accurate)
   • Alternative: In-app pure-tone test with stereo headphones in quiet environment
   • Ensure separate thresholds for left and right ear at all 8 frequencies
2. Prescription Selection
   • Adults, general use: NAL-NL2
   • Children, severe loss, audibility priority: DSL v5
   • Application automatically calculates frequency-specific gains
3. Hearing Aid Activation
   • Patient connects stereo headphones/AirPods
   • Application automatically detects stereo mode and applies per-ear processing
   • Start hearing aid and verify status shows "STEREO mode"
4. Feedback Management
   • Set overall gain to patient's comfortable listening level
   • Run feedback detection test (3 seconds)
   • Review and apply detected feedback frequencies
   • Re-test if feedback persists
5. Fine-Tuning
   • Patient provides feedback on sound quality in different environments
   • Adjust individual frequency bands as needed (± 5 dB increments recommended)
   • Consider using presets as starting points for specific situations
   • Save custom presets for patient's preferred settings
6. Tinnitus Management (if applicable)
   • Assess tinnitus characteristics (frequency, loudness, laterality)
   • Select appropriate therapeutic sound (white/pink noise or nature sounds)
   • Set sound therapy at "mixing point" (barely audible with tinnitus)
   • Can be used simultaneously with hearing aid amplification
   • Provide counseling on habituation process and realistic expectations
7. Patient Education
   • Demonstrate overall volume control
   • Explain background operation (works with screen locked)
   • Show how to switch between presets
   • Recommend gradual acclimatization (start with lower gain, increase over 2-4 weeks)

Follow-Up & Adjustment

✅ Clinical Advantages

⚠️ Limitations & Contraindications

📚 Evidence Base & References

Prescription Formulas

Supporting Research

• WHO Hearing Loss Classification: WHO (2021). World Report on Hearing. Geneva: World Health Organization.
• Audiometric Test Protocols: ASHA (2005). Guidelines for Manual Pure-Tone Threshold Audiometry.
• Feedback Management: Chung, K. (2004). Challenges and recent developments in hearing aids: Part I. Speech understanding in noise, microphone technologies and noise reduction algorithms. Trends in Amplification, 8(3), 83-124.
• Tinnitus Retraining Therapy: Jastreboff, P. J., & Hazell, J. W. (2004). Tinnitus Retraining Therapy: Implementing the Neurophysiological Model. Cambridge University Press.
• Sound Therapy Efficacy: Henry, J. A., et al. (2008). General review of tinnitus: Prevalence, mechanisms, effects, and management. Journal of Speech, Language, and Hearing Research, 51(5), 1276-1294.

📞 Clinical Support & Resources

For Audiologists

For Patients

🎯 Clinical Summary