Audiograms are usually the first-line investigation that is performed when a patient complains of hearing difficulties. They are relatively easy to interpret as long as some simple rules are followed:

• anything above the 20dB line is essentially normal (marked in green on the audiogram below)
• in sensorineural hearing loss both air and bone conduction are impaired
• in conductive hearing loss only air conduction is impaired
• in mixed hearing loss both air and bone conduction are impaired, with air conduction often being 'worse' than bone