الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
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Abstract
Conductive hearing loss (CHL) is one of the commonest ear diseases. It can result from multiple causes in the external canal, in the tympanic mem-brane and in the middle ear. chronic suppurative otitis media (CSOM) with tympanic membrane perforation is the one of the commonest infective conditions. It accounts for almost 19.5% of ear conditions.
The general rule of thumb in hearing and VEMP is that conductive hearing loss obliterate VEMP. VEMP recording method clinical practice requires using loud sound stimulation. Sound transmitted VEMP require conduction of sound to the inner ear which means that an intact middle ear trans-mission system is needed Air conducted (AC) stimulating sounds, trans-mitted through the middle ear conduction system fail to elicit VEMP in those with conductive hearing loss.
To overcome this attenuation of stimulation, taping of the skull and bone conduction (BC) stimulation have been proposed as possible solutions to elicit VEMP in CHL. Bone conduction tone burst stimulation can evoke VEMP using frequencies around 500 Hertz (HZ). Clinical bone vibration generally requires additional amplification to produce strong enough stimuli for VEMP testing.
The aim of this study was to investigate the VEMP responses in conductive hearing loss using bone conduction stimulation.
The study comprised of 26 adult patients age ranged from 18 to 50 years old suffering from many causes that result in conductive hearing loss and the control group comprised of 10 normal age and gender matched individuals. In the selection of patients, we followed the exclusion criteria
in the form of excluding patients with sensorineural hearing loss and mixed hearing loss.
All patients were subjected to full history taking, pure tone audiogram (PTA), tympanometry, acoustic reflexes, speech reception threshold, word discrimination score and VEMP testing by air and bone stimulation
The result of this study revealed that the percentage of present VEMP waves by AC stimulation was 35 % for BC stimulation the rate increased to 69 %. A significant difference existed in the response rate between AC and BC waves. The study found good percentage of recordable VEMP waves by BC stimulation in conductive hearing loss with no significant difference in latency from the control group.
We conclude from this study that VEMP can be used to test the presence of conductive hearing loss. BC stimulation can be used to evoke VEMP waves with high degree of accuracy when conductive hearing loss present all cases with absent VEMP waves for AC stimulation should have a trail to elicit VEMP waves by BC stimulation.