Sensorineural (sensorineural) hearing loss: diagnosis
Last reviewed: 23.04.2024
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[Physical examination
Given the complexity of the diagnosis of neurosensory hearing loss, it is necessary to conduct a comprehensive clinical examination of the patient with the participation of an otoneurologist, a therapist. Neurologist, ophthalmologist (to assess the condition of the fundus and retinal vessels). Endocrinologist (for carrying out tests for glucose tolerance and thyroid function studies), as well as on indications, consultation of a traumatologist.
Laboratory diagnostics of sensorineural hearing loss
It is necessary to conduct a general clinical and biochemical study of blood.
Instrumental study of sensorineural hearing loss
When otoscopic pathological changes are not detected. The tympanic membrane and the external ear canal are not changed.
To assess the state of the auditory analyzer, a number of studies are carried out. With acuity, a significant decrease in the perception of whispered and spoken speech is revealed in comparison with the norm. Tumor methods of research: with sensorineural hearing loss, the positive experiments of Rinne and Federici are determined; in the Weber experiment, the tuning fork C12S-C512 laterals to a better hearing or healthy ear. Patients with suspected neurosensory deafness need a tone threshold audiometry. As a rule, the descending configuration of the curves is revealed in connection with the deterioration of perception of predominantly high tones, the lack of an air-hole interval: the breakage of the curves at the frequencies of their maximum decrease; noise in the ears of the high-frequency spectrum. With above-threshold audiometry, a positive phenomenon is observed to accelerate the increase in loudness. The thresholds of audibility of ultrasound are increased in comparison with the norm, there is a lateralization of sound in a healthy or better hearing ear.
In young children, subjective play audiometry or objective audiometry is used to record the state of the auditory function: registration of short-latency SVPs and UAE. In children, recording of auditory evoked potentials is the main (often the only) method that can diagnose a hearing defect. For early diagnosis of hearing loss in newborns, a system of audiologic screening has been developed that can be used in maternity hospitals, providing for the registration of UAE and short-latency SVP.
All patients with suspected neurosensory deafness need to conduct objective audiometry to determine the topic of the lesion. Measurement of the acoustic impedance of the middle ear makes it possible to assess the state of the conducting system of the middle ear and to exclude changes in the sound system. With neurosensory hearing loss, as a rule, a type A tympanogram is registered, which indicates the normal state of the sound-conducting system of the middle ear. The values of registration of acoustic reflexes largely depend on the level of lesion of the auditory analyzer and the degree of hearing loss in a particular patient. Electrochlear surgery is an objective method that allows differential diagnostics of neurosensory hearing loss due to internal ear hydroids. Registration of the UAE makes it possible to assess the state of sensory structures of the inner ear and, in particular, the outer ear cells of the inner ear, which provide normal processes of sound transformation in the inner ear. Short-latent SVPs in some cases allow differential diagnosis of retrocochlear hearing loss,
To assess the state of the equilibrium system, vestibulometric tests are conducted: couplometry with threshold and suprathreshold stimuli, caloric assay, fisturography, indirect selective otolithometry.
In the complex examination, chest X-ray examination, cervical spine in 2 projections, temporal bones in the projections of Stenvers, Schueller and Maner are performed. The most informative is CT, MRI. For the study of cerebral hemodynamics extracranial and transcranial ultrasonic dopplerography of the main vessels of the head or duplex scanning of cerebral vessels is performed.
Differential diagnosis of sensorineural hearing loss
Sensorineural hearing loss should be differentiated from pathological conditions that cause deafness associated with dizziness. Hearing loss by neurosensory type is observed in the following diseases:
- acute disturbance of cerebral circulation in vertebral-basilar insufficiency
- Ménière's disease:
- tumors in the region of the cerebellopontine angle;
- fistula labyrinth;
- multiple sclerosis.