[Somatic tinnitus (review). A consequence of plasticity and bimodal integration in the dorsal cochlear nucleus]. / Les somatoacouphènes (revue) : une conséquence de la plasticité et de l'int gration bimodale dans le noyau cochléaire dorsal.

Somatic tinnitus is a peculiar tinnitus type that can be defined as a tinnitus that can be modulated in intensity and/or pitch by manipulating some regions of the head and neck but also as tinnitus associated with facial pain or dysesthesis in the same area. Those areas are innervated by the trigeminal nerve and the cervical plexus. This can be explained by functional connections between the trigeminal system and the auditory brainstem and mid-brain. A literature overview shows how different messages coming from the head and neck are able to modulate the hearing information. Tinnitus is generated by an increase of the spontaneous discharges of the dorsal cochlear nucleus neurons, tonotopic reorganisation and an increase of the neural synchronism in the auditory cortex. Trigeminal stimulations have an influence on the activity of the dorsal cochlear nucleus especially in case of an associated hearing loss.

[Pathophysiology of cholesteatoma]. / La physiopathogénie des cholestéatomes.

OBJECTIVE: To describe the development of cholesteatoma using current knowledge. METHOD: Review of the literature. RESULTS: Cholesteatoma describes a mass of keratin (skin) in the middle ear which consists of a perimatrix and matrix. There are at least three kinds of cholesteatoma in the middle ear one resulting from invagination (retraction's pocket), another from migration and the last one from congenital inclusion. Cholesteatoma needs three successive inflammatory phases, the first leading to a retraction pocket, the second leading to pathology of the epidermis and of the floor of the external auditory canal and the third is the actual phase of cholesteatoma with invasion and middle ear auto-destruction with bone resorption. In this last phase, many factors play a role, collagenasis, osteoclats, cytokines, NO, bacteria and their biofilm and rupture of the retraction pocket. CONCLUSION: Cholesteatoma is an inflammatory disease of the ear caracterised by bone resorption. Current research is starting to appreciate the important role the immune system plays in the pathophysiology of cholesteatoma.