Carha's notch is an audiometric finding associated with:

Carha's notch is named after Raymond Carha who described this characteristic audiogram finding first. Carha's notch refers to a dip in bone conduction threshold occurring at 2000 Hz. This is seen in patients with otosclerosis. Otosclerosis is a disorder of bone growth which affects the stapes and bony labyrinth of the cochlea. This disease is characterized by resorption of bone and new spongy bone formation around the stapes and oval window which finally result in fixation of stapes within the oval window, resulting in conductive hearing loss.