Chronic hearing loss

Prolonged (more than three months) hearing loss - a decrease in the normal hearing threshold - is medically defined as chronic hearing loss or chronic hypoacusis.

Epidemiology

According to some reports, chronic hearing loss of one degree or another affects more than 5% of the world's population, and in nearly 50% of all cases, the cause is excessive noise exposure. In the US alone, excessive noise exposure - through the use of headphones, audio players, computers and mobile gadgets - causes permanent hearing damage in 12.5% of children and adolescents.

Hearing loss due to otitis media occurs in 12-15% of cases and in auditory neuritis in about 5-6% of cases.

Nearly one-third of people 65-75 years old and more than half of seniors over 75 suffer from senile hearing loss.

Causes of the chronic hearing loss

Hearing loss can occur for a variety of reasons, which in otiatrics and otolaryngology include:

• Noise exposure - chronic acoustic trauma, which leads to occupational noise hypoacusis;
• Exposure of the inner ear structures to various toxic substances;
• adhesive or exudative otitis media, as well as chronic suppurative otitis media, with chronic otitis media and hearing loss with impaired sound conducting structures of the ear being etiologically related in more than half of cases; [1], [2], [3]
• chronic labyrinthitis (inflammation of the inner ear) of bacterial, viral or post-traumatic origin;
• presence of a cystic mass - middle ear cholesteatoma;
• otosclerosis;
• Scarring and degenerative changes of the tympanic cavity - tympanosclerosis;
• endolymphatic hydrocele of the inner ear - Meniere's disease;
• Neuritis (inflammation) of the VIII pair of cranial nerves - prevertebral-cochlear nerve;
• vestibular schwannoma or auditory nerve neurinoma;
• Hearing loss in patients with chronic renal failure. [4]

Read also:

• Causes of hearing loss
• Causes of hearing loss

Age-related chronic bilateral hearing loss, that is, bilateral senile hearing loss develops due to deterioration of the blood supply to the labyrinth of the inner ear (by ischemia or stenosing atherosclerosis).

Chronic hearing loss in children can result from alcohol consumption by the expectant mother; prematurity (birth weight less than 1500 g) and premature birth (often with oxygen deficiency in the infant); birth trauma to the head; nuclear jaundice (hyperbilirubinemia) in the newborn. In cases of neonatal hyperbilirubinemia, bilateral chronic hearing loss begins to occur in 40% of children over 5-6 years of age.

In addition, significant hearing loss occurs in children with congenital chromosomal abnormalities (Treacher-Collins, Alport, Pegent, Konigsmark, etc.).

• See: Hearing loss in a child
• Developmental abnormalities of the ear

Risk factors

Factors that increase the risk of developing chronic hypoacusis are also many, and they include:

• genetic abnormalities and hereditary predisposition;
• immunodeficiency conditions;
• meningitis;
• Ear labyrinth lesions in syphilis;
• damage to the tympanic membrane of various origins (including complete rupture);
• brain injuries with fracture of the temporal bone, which leads to inner ear injuries;
• adenoma and osteoma of the middle ear;
• Stenosing carotid atherosclerosis;
• use of ototoxic drugs: aminoglycoside antibacterials (Neomycin, Kanamycin, Gentamicin), glycopeptide antibiotics (Vancomycin) and macrolide antibiotics (Erythromycin and its derivatives), as well as loop diuretics (Furosemide), nitrofuran derivatives (Furazolidone) and some NSAIDs (non-steroidal anti-inflammatory drugs).
• loud noise. [5], [6]

There are also perinatal risk factors, particularly TORCHS or intrauterine infections and alcohol use during pregnancy.

Pathogenesis

Specialists consider the pathogenesis of chronic hypoacusis, taking into account its main types.

Chronic conductive hearing loss (conductive or transmissive) develops after chronic otitis media or recurrent middle ear inflammation, otosclerosis and tympanosclerosis, and narrowing of the external auditory canal due to bony growths (exostoses) in the ear canal. This can impair the mobility of the auditory ossicles (ossicula auditus), which negatively affects the mechanical system that transmits vibrations from the outer ear (auris externa) and the tympanic membrane (membrana tympani) to the inner ear (auris interna). [7] For more details, see Conductive hearing loss.

What is chronic sensorineural hearing loss, perceptual or chronic sensorineural hearing loss ref. - Neurosensory (sensorineural) hearing loss. Its pathogenesis is based on damage to the sound-receptive apparatus (auditory analyzer) located inside the cochlea (cochlea labyrinth) of the inner ear, as well as the prevertebral cochlear nerve (nervus vestibulocochlearis) and the primary auditory cortex (temporal lobe) of the brain. [8] Read more in the material - Sensorineural hearing loss - Causes and pathogenesis

The mechanism of bilateral senile hearing loss is attributed to the loss of receptor cells in the main membrane of the cochlea of the inner ear - the hair cells of the organ of Cortium (organum spirale). It is these cells that are able to convert the mechanical movement of sound waves into nerve (electrical) impulses that are transmitted to the brain.

In some cases - such as chronic otitis media with damage to the bony structures of the middle ear and the outer and inner hair cells - there is a chronic mixed hearing loss in which the hearing loss has conductive and neurosensory elements.

Symptoms of the chronic hearing loss

Chronic hearing loss is a decrease in the perception of sounds and their volume (intensity). And the first signs of hypoacusis may be manifested by the need to interject what the interlocutor has said and increase the volume of sound sources (because all sounds seem deaf or muffled), as well as difficulty in understanding speech in the presence of background noise.

In addition, symptoms of hearing loss include noise and/or ringing in the ear; sensation of congestion in one or both ears, pressure in the ears, and pain with sounds of a certain intensity and frequency (in sensorineural type of hearing loss); impaired hearing when chewing; and difficulty in determining the direction of sound.

Hearing loss can be in one ear: chronic left-sided sensorineural hearing loss or chronic right-sided sensorineural hearing loss. There is also chronic bilateral sensorineural hearing loss.

The child may lack response to quiet sounds and have difficulty hearing the speech of others and localizing sounds.

For more details on the peculiarities of the perceptual type of hearing loss, see Sensory Neurosensory (sensorineural) hearing loss - Symptoms

Depending on the level of increase in the strength of sound that is picked up by the ear, there are different degrees of hyperacusis: [9]

• 25-40 dB (decibels) - Grade 1 chronic hearing loss, which is considered mild and the person can hear whispers from up to three meters away and speech of normal volume from four meters away);
• 40-55 dB - chronic hearing loss of the 2nd degree (moderate or average, in which speech of normal volume is perceived normally from three meters, and whispers - up to one meter);
• 55-70 dB - moderately severe or chronic hearing loss of the 3rd degree (when whispering can be heard if spoken into the ear, and normal speech can be heard from a distance of no more than one and a half meters);
• 70-90 dB - chronic hearing loss of 4th degree (severe, followed by complete hearing loss).

Complications and consequences

The main complications and consequences of chronic hearing loss in adults are: psychopathies, the appearance of isolation and social isolation; neuroses, depression. In the elderly, the risks of progression of dementia and personality degradation with chronicization of depression increase.

With chronic hearing loss, there is delayed speech development in early childhood and/or lagging behind age-appropriate norms, and communication difficulties and psychological or mental health problems later in life.

Diagnostics of the chronic hearing loss

Hearing loss is diagnosed by examining the ear and testing hearing.

Instrumental diagnosis includes otoscopy, examination of hearing parameters by audiometry (tone threshold and impedance), electrocochleography and tympanometry, and a skull x-ray, CT scan or ear and temporal bone x-ray is taken.

See also - Diagnosing hearing loss in children

Differential diagnostics is aimed at finding out the causes of hearing loss. [10]

Treatment of the chronic hearing loss

In sensorineural hearing loss, treatment may be medication, and physiotherapeutic treatment (ultraphonophoresis of the tympanic cavity with drug solutions).

In case of mixed type hearing loss, medications that improve microcirculation and promote oxygen supply to the tissues are prescribed, such as, Betagistin (Betaserec, Vergostin, Vestagistin), Piracetam with Cinnarizine, as well as Pentoxifylline (Agapurin, Latrin) and Cavinton (Vinpocetine).

Treatment with herbs, or rather medicinal plants suggests taking Ginkgo biloba leaf extract that activates cerebral blood circulation, e.g. Bilobil capsules .

In case of conductive hypoacusia, surgical treatment is possible. Myringoplasty (tympanoplasty) can be performed to reconstruct the tympanic membrane; ossiculoplasty is performed to reconstruct the middle ear ossicle chain, and when the stapes are immobilized in patients with otosclerosis, sound conduction is restored by stapedectomy. [11]

For children with severe hearing loss, a cochlear implant can be used to stimulate the auditory nerve. And for patients with bilateral hearing loss, the best solution is hearing aids with sound-amplifying hearing aids. [12]

More useful information in the materials:

• Hearing loss: treatment, prevention and prognosis
• Treatment of sensorineural hearing loss
• Developmental anomalies of the ear - Treatment

Prevention

The main prevention of hearing loss is to minimize noise exposure to the structures of the ear, treat otitis media and all diseases affecting hearing.

Forecast

Chronic hearing loss can progress to complete deafness, so the prognosis for hearing loss is directly related to the etiology of the disorder.

List of authoritative books and studies related to the study of chronic hearing loss

Books:

1. "Chronic Conductive Hearing Loss" (by Colin L. W. Driscoll, 2005) - This book provides an overview of the causes and treatment of chronic hearing loss associated with conductive hearing loss.
2. "Sensorineural Hearing Loss: A Caring Approach to Counseling" (by Liz Cherry, 2007) - A book that covers the challenges and approaches to counseling patients with sensory hearing loss.

Research and articles:

1. "Prevalence of Hearing Loss in Adults in the United States" (authors: Frank R. Lin and team of authors, 2011) - A study assessing the prevalence of hearing loss in adults in the United States.
2. "Tinnitus and Hearing Loss in the Aging Population" (Authors: Authors Collective, 2019) - An article examining the relationship between hearing loss and hearing loss in the aging population.
3. "Chronic Tinnitus: Assessment and Comparison of Treatment Efficacy" (Authors: Authors' Collective, 2020) - A study comparing the effectiveness of different treatments for chronic hearing loss.
4. "The Prevalence of Chronic Tinnitus and Vertigo" (by David M. Baguley, 2006) - A study discussing the prevalence of chronic hearing loss (tinnitus) and vertigo.
5. "Epidemiology of Tinnitus" (authors: Charles I. Berlin and Berthold Langguth, 2015) - An overview of the epidemiology of tinnitus, including the chronic form.
6. "Chronic Tinnitus: Comparison of Epidemiological and Clinical Data From the General Population With Data From Clinical Tinnitus Centers" (by Patrick Landgrebe et al., 2010) - A study comparing data on chronic tinnitus with patients from the general population and clinical centers.

Literature

Palchun, V. T. Otorhinolaryngology. National manual. Brief edition / Edited by V. V. Т. Palchun. - Moscow : GEOTAR-Media, 2012.