Nonorganic Hearing Loss

SRT-PTA Discrepancy

The pure tone average (PTA) of the 500, 1000 and 2000 Hz thresholds and the SRT normally agree within reasonable limits. In contrast to the agreement between the SRT and PTA in patients with real hearing losses, the SRT is often better (lower) in patients with functional hearing losses. An SRT-PTA discrepancy of 12dB or more is considered to indicated a nonorganic hearing loss. For example, if a patient has a PTA of 47 dB HL and an SRT of 30 dB HL, he would be considered to have a nonorganic hearing loss because his SRT is better than his PTA by > or = 12 dB. A significant SRT-PTA discrepancy has been shown to be the best audiometric indicator of functional losses.