Degree of hearing loss Based on PTA in 500, 1k, 2K HZ (WHO 1980 criteria) Mild HL(<40 dB) Middle HL(41-55dB) Middle-severe HL(56-70 dB) Severe HL 71-90dB) Profound HL(>90 dB)Degree of hearing loss ◼ Based on PTA in 500, 1k, 2k Hz (WHO 1980 criteria) ◼ Mild HL (<40 dB) ◼ Middle HL (41-55dB) ◼ Middle-severe HL (56-70 dB) ◼ Severe HL (71-90 dB) ◼ Profound HL (>90 dB)