[Recent experimental and clinical findings retarding an interlabyrinthine connection]

In his experiments on the origin and site of formation of perilymph, which he conducted using radioactive substances in 1961. Schreiner also came across a surprising secondary finding, namely that rapid substance exchange takes place between the perilymph spaces of both inner ears. This rapid transition was only demonstrated for real solutions, such as low-molecular radioactive sodium phosphate, whereas it was greatly delayed for C14-labeled amino acids. No patency was demonstrated for particles which approach the limit of visibility under a light microscope, such as cell granules consisting of radioactively labeled mitochondria from rabbits. The graded patency between perilymph spaces in relation to the molecule size of the radioactive substances added indicates a direct connection between the perilymph spaces of both inner ears. This interlabyrinthine connection first postulated by Schreiner was controversial at the time but was soon confirmed by several authors in Germany and abroad and has been known since then as the "Schreiner effect" (1964).

In spite of these publications, the hypothesis of an interlabyrinthine connection was ignored for over 20 years until the American authors Harris et al. took up the topic once again in 1985, because of clinical investigations. They termed this phenomenon "sympathetic cochleo-labyrinthitis" in line with sympathetic ophthalmia. In pathogenetic terms, these authors suspect autoimmunological genesis. It has not been clarified which anatomical and immunological routes are taken to affect the labyrinths. Possibilities being discussed include connections via the perineural lymph sheath,

In recent times, the perivascular spaces have also been considered, and Maher et al. (1997) attempted to substantiate this theory by demonstration using contrast media. In 1997, W. Zenker, the Zurich anatomist, conducted experiments using ferritin and was the first to demonstrate movement of such molecules within the dura. He believes that the transition of substances from one inner ear to the other is via CSF movements in the subarachnoid space and in the perivascular compartment of numerous small vessels crossing in a median plane such as veins of the clivus and plexus cavernosi but also venules and arterioles.