Born 1935, Brooklyn, NY USA

Ph.D. 1965, The Hebrew University

Lecturer, 1966

Senior lecturer, 1970

Associate professor, 1975

Professor since 1980

 

 

 

 

Mechanism of cochlear activation at low sound intensities:
Holes were made in the bony shell of the inner ear without causing change in auditory threshold. We have also shown that auditory stimulation of an ear of one animal can evoke responses in an ear of a second animal, provided the two ears are coupled to each other by a saline filled tube. These results have lead to the suggestion that cochlear activation at low sound intensities does not involve a basilar membrane traveling wave. It is likely that fluid borne sound pressures can directly activate the outer hair cells.

 

Sohmer, H., Freeman, S. and Perez, R. Semicircular canal fenestration - improvement of bone- but not air-conducted auditory thresholds. Hear. Res. 187:105-110 (2004).
Sohmer, H., Sichel, J.Y. and Freeman, S. Cochlear activation at low sound intensities by a fluid pathway. J. Basic Clin. Physiol. Pharmacol. 15:1-14 (2004). [PDF]
Sichel, J-Y., Perez, R., Freeman, S. and Sohmer, H. Mechanism of cochlear excitation at low intensities. In press 2005: J. Basic Clin. Physiol. Pharmacol. [PDF]

 

Jean-Yves Sichel, Sharon Freeman, Ronen Perez, Haim Sohmer (2006): Transmission of oto-acoustic emissions within the cochlea. Journal of Basic & Clinical Physiology. & Pharmacology 17:143-157. [PDF]

Mechanism of bone conduction stimulation:
Experiments in this laboratory have shown that bone conduction stimulation of the inner ear is not limited to a pathway involving skull bone vibration by the bone vibrator which is then transmitted by a completely bony pathway, along skull bones to the bony cochlear shell. In fact, it seems that a major pathway involves the transmission of skull bone vibrations directly into the skull cavity (brain and CSF) and from there, via fluid communicating channels, to the fluids of the inner ear. This is being studied in animals and in humans.

 

Freeman, S., Sichel, J.Y. and Sohmer, H. Bone conduction experiments in animals - evidence for a non-osseous mechanism. Hear. Res. 146:72-80 (2000).
Sohmer, H., Freeman, S., Geal-Dor, M., Adelman, C. and Savion, I. Bone conduction experiments in humans - a fluid pathway from bone to ear. Hear. Res. 146:81-88 (2000).
Sohmer, H., Perez, R., Sichel, J.Y., Priner, R. and Freeman, S. The pathway enabling external sounds to reach and excite the fetal inner ear. Audiol. Neurootol. 6:109-116 (2001).
Sohmer, H. and Freeman, S. The pathway for the transmission of external sounds into the fetal inner ear. J. Basic Clin. Physiol Pharmacol. 12:91-99 (2001).
Sohmer, H. and Freeman, S. Further evidence for a fluid pathway during bone conduction auditory stimulation. Hear. Res. 193:105-110 (2004).

Conductive HL: The presence of fluid in the middle ear cavity is accompanied by a CHL. The mechanisms of this loss are being studied.
Priner, R., Freeman, S., Perez, R. and Sohmer, H. The neonate has a temporary conductive hearing loss due to fluid in the middle ear. Audiol. Neurootol. 8:100-110 (2003).
Priner, R., Perez, R., Freeman, S. and Sohmer, H. Mechanisms responsible for postnatal middle ear amniotic fluid clearance. Hear. Res. 175:133-139 (2003).
Jeselsohn, Y., Freeman, S., Segal, N. and Sohmer, H. Assessment of the factors contributing to hearing loss in serous otitis media. Otology & Neurotology 26: in press, 2005.


The Effects of Noise Exposure on Hearing: By recording the responses of the ear to sound, one can assess the site(s) damaged by noise.
Freeman, S., Khvoles, R., Cherny, L. and Sohmer, H. Effect of long-term noise exposure on the developing and developed ear in the Rat. Audiol. Neurootol. 4:207-218 (1999).
Fraenkel, R., Freeman, S. and Sohmer, H. The effect of various durations of noise exposure on auditory brainstem response, distortion product otoacoustic emissions and transient evoked otoacoustic emissions in rats. Audiol. Neurootol. 6:40-49 (2001).
Perez, R., Freeman, S., Cohen, D. and Sohmer, H. Functional impairment of the vestibular end organ resulting from impulse noise exposure. Laryngoscope 112:1110-1114 (2002).
Fraenkel, R., Freeman, S. and Sohmer, H. Use of ABR threshold and OAEs in detection of noise induced hearing loss. J. Basic Clin. Physiol Pharmacol. 14:95-118 (2003).
Fraenkel, R., Freeman, S. and Sohmer, H. Susceptibility of young adult and old rats to noise-induced hearing loss. Audiol. Neurootol. 8:129-139 (2003).
Perez, R., Freeman, S. and Sohmer, H. Effect of an initial noise induced hearing loss on subsequent noise induced hearing loss. Hear. Res. 192:101-106 (2004).

Differentiation between cochleotoxic and vestibulotoxic agents:
Making use of the ability to record both vestibular and auditory evoked potentials in experimental animals, the specific site of lesion of ototoxic drugs and agents can be easily evaluated.

Freeman, S., Priner, R., Mager, M., Sichel, J.Y., Perez, R., Elidan, J. and Sohmer, H. Use of evoked potentials to objectively differentiate between selective vulnerability of cochlear and vestibular end organ function. J. Basic Clin. Physiol Pharmacol. 11:193-200 (2000).
Perez, R., Freeman, S., Sohmer, H. and Sichel, J.Y. Vestibular and cochlear ototoxicity of topical antiseptics assessed by evoked potentials. Laryngoscope 110:1522-1527 (2000).
Sichel, J.Y., Eliashar, R., Plotnik, M., Sohmer, H. and Elidan, J. Assessment of vestibular ototoxicity of ear drops by recording of vestibular evoked potentials to acceleration impulses. Am. J. Otol. 21:192-195 (2000).
Perez, R., Freeman, S., Cohen, D., Sichel, J.Y. and Sohmer, H. The differential vulnerability of the inner ear end-organs to several external factors. J. Basic Clin. Physiol Pharmacol. 14:85-93 (2003).