This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
Acoustic neuroma causes - 
Select and explain. 
A. Cochlear deafness, B. Retrocochlear deafness, C. Conductive deafness, D. None of the above
B: Retrocochlear deafness
Answer: B: Retrocochlear deafness 
Explanation: Ans. is 'b' i.e., Retrocochlear deafness o The clinical features depend on the extent of tumor and involved structureWhen tumor is still confined to the internal auditory canalCochleovestibular symptoms are the earliest symptoms of acoustic neuroma when tumour is still confined to internal auditory canal. The commonest presenting symptoms are unilateral deafness or tinnitus, or a combination of both. Hearing loss is retrocochlear sensorineural type. There is marked difficulty in understanding speech, out of proportion to the pure tone hearing loss, a characteristic feature of acoustic neuroma. Vestibular symptoms are imbalance or unsteadiness. True vertigo is very rare.When tumor extends beyond IAC and involves other structurescranial nerve > It is the earliest nerve to be involved. There is reduced corneal sensitivity and loss of corneal reflex which is the earliest sign of acoustic neuroma. Numbness or paraesthesia of face may occur. Involvement of Vth nerve indicates that tumor is roughly 2.5 cm in diameter and occupies the CP angle.VIIth nerve Sensory fibres of facial nerve are involved. There is hypoesthesia of posterior meatal wall (Hitzelberg's sign), loss of taste, and loss of lacrimation on Schirmer's test. Motor fibres are more resistant.IXth and Xth nerves Dysphagia and hoarseness due to palatal, pharyngeal and laryngeal paralysis, a Brainstem Ataxia, weakness, numbness of arms & legs, exaggerated tendon reflexes.Cerebellum Ataxia, Dysdiadochokinesia, Nystagmus.Due to raised ICT:- Headache, neusea, vomiting, diplopia due to VI* nerve involvement, and papilloedema.