What type of hearing loss is typically indicated by Carhart's notch?

Carhart's notch is primarily associated with conductive hearing loss, specifically indicating a characteristic dip at 2000 Hz in the bone conduction threshold on an audiogram. This phenomenon is often observed in patients with otosclerosis, a condition where abnormal bone growth around the stapes bone in the middle ear can lead to a reduction in sound transmission. The presence of this notch highlights the disturbance in how sound is conducted through the middle ear structures, which is a hallmark of conductive hearing loss.

While mixed and sensorineural hearing losses can present their own unique patterns and features on an audiogram, they do not typically exhibit Carhart's notch, making this characteristic distinct to conductive issues. Central auditory processing disorder pertains to difficulties in the processing of auditory information in the brain rather than a direct issue with hearing loss as measured by an audiogram. Thus, the identification of Carhart's notch is a clear indicator of conductive hearing loss specifically.