BHUBANESWAR: When Alka Yagnik, the iconic voice behind numerous Bollywood hits, revealed on social media that she has been diagnosed with rare sudden sensorineural hearing loss (SSNHL), it sparked widespread concern and brought to fore the rising incidence of sensorineural hearing loss cases across India. Also known as sudden deafness, SSNHL is a rapid-onset form of sensorineural hearing loss.
A noticeable reduction in hearing abilities over a period of 72 hours or less is a major alert. It can affect one or both ears and often occurs without any preceding symptoms, making it particularly alarming.
There are mainly four types of sensorineural hearing loss - unilateral, bilateral, asymmetrical, and sudden sensorineural hearing loss. While unilateral sensorineural hearing loss (USNHL) has been found to affect 8-15% of the Indian population, 1-4% people are affected by bilateral hearing loss. SSNHL affects roughly five to 20 in one lakh people.
Although USNHL is more common in nonelderly men, SSNHL has emerged as a growing public health concern post-Covid-19. According to health experts, since the novel coronavirus attacks the human organs, it first results in loss of sense of taste or hearing. Sensorineural hearing loss is generally caused by damage to the structures in the inner ear or auditory nerve. Some also suffer from chronic sensorineural hearing loss that develops gradually over time and typically progresses slowly.
“Sensorineural hearing loss is mostly found among adults accounting for more than 90% of hearing loss in elderly people. Whereas, SSNHL can affect people of all age groups. Common causes of SSNHL include exposure to loud noises, genetic factors, or the natural aging process; while viral infection is believed to be the most common cause of sudden hearing loss,” said Dr Radhamadhab Sahu, head of ENT and skull base surgery at SUM Ultimate Medicare, Bhubaneswar.
Causes and symptoms
SSNHL can strike unexpectedly and occur at any age in a short time. It has left many individuals grappling with sudden and severe hearing impairment. Medical professionals have identified multiple triggers and a range of potential causes behind the medical condition.
“Nowadays we are attending many patients, mostly children, who are suffering from sudden hearing loss after mumps infection. It can also affect adults by common viruses like herpes and varicella. Other causes are chemotherapy drugs, severe noise trauma, sudden bleeding in tumours, meningitis, stroke, painkiller overdose, and antitubercular drugs,” Dr Sahu said.
While the exact cause remains unknown in many cases, several key factors could be responsible. Apart from idiopathic origins, viral infections, autoimmune diseases, trauma, ototoxic medications, circulatory problems, tumours, neurological disorders and metabolic disorders are some of the causes.
Senior otolaryngologist at Manipal Hospitals Dr Samarendra Behera says SSNHL occurs when the inner ear and hearing nerve (cochlear nerve) gets damaged. Among multiple causes behind SSNHL, old age is the primary cause. Other causes are head injury, viral infection of the inner ear, cochlear nerve, tumours, and exposure to loud noise, etc. In approximately half of SSNHL cases, no specific cause can be identified, he adds.
Common culprits of SSNHL include viruses that cause mumps, measles, or influenza, which may lead to inflammation or damage in the inner ear. Autoimmune conditions and diseases such as systemic lupus erythematosus and multiple sclerosis might trigger SSNHL by affecting the inner ear or auditory nerve.
“High doses of antibiotics and certain chemotherapy agents can have adverse effects on the auditory system, leading to SSNHL. Tumours affecting the auditory nerve and neurological conditions such as multiple sclerosis can also affect the auditory pathways in the brain, sometimes resulting in sudden hearing loss,” said Dr Girish Anand, consultant (ENT surgery) at Aster CMI Hospital, Bengaluru.
The hallmark symptom of SSNHL is a sudden decrease in hearing ability. Many affected individuals report experiencing ringing, buzzing, or hissing sounds in the ear. This symptom often accompanies sudden hearing loss. Another common symptom is a spinning sensation or dizziness that can be severe and disorienting. “The condition is diagnosed through physical examination, hearing tests, such as audiometry, tympanometry, and auditory brainstem response,” said Dr Anand.
Treatment
Sensorineural hearing loss isn’t a life-threatening condition, but it limits a person’s ability to communicate if not properly managed. Timely intervention is the key for the best outcomes. Corticosteroids are often the first line of treatment for SSNHL. Medications such as prednisone are prescribed to reduce inflammation and swelling in the inner ear, which may help restore hearing. Treatment typically starts with a high dose and tapers off over several weeks.
Advanced therapies like hyperbaric oxygen therapy, which involves breathing pure oxygen in a pressurised room or chamber, helps increase oxygen delivery to the inner ear and promote healing. If a viral infection is suspected as the cause of SSNHL, antiviral drugs are prescribed. Treating any underlying health issues, such as autoimmune diseases or metabolic disorders, is also crucial.
Dr Lakshmi Ranjit, associate consultant (ENT) at VPS Lakeshore, Kochi, said steroids have been found to be effective in treating
SSNHL and they include oral prednisone or intratympanic steroid injection. Proper diagnosis and treatment are important in recovery. “Delay in treatment can lead to a reduction in the rate of recovery. In people who have experienced dizziness or other complications, the chances of recovery are less,” Dr Ranjit added. Since there is no guaranteed cure for SSNHL, early intervention could be helpful. The first few hours during loss of hearing is called the golden hour. If recognised and treatment is initiated, the recovery chances are high. In cases where hearing loss persists despite treatment, hearing aids or cochlear implants are recommended. These devices can help manage long-term hearing loss, Dr Sahu said.
Preventive measures
Amid growing concerns about SSNHL, health experts have emphasised on taking preventive measures. Exposure to high noise levels is a known risk factor for hearing loss. To prevent SSNHL, it’s crucial to protect your ears in noisy environments. As certain medications can have harmful effects on the inner ear, people should always follow medical advice and consult doctors about the potential side effects of any prescribed or over-the-counter medications.
Dr Behera says managing chronic health conditions like diabetes and hypertension through regular check-ups, a balanced diet, and a healthy lifestyle can help maintain good hearing health. “Vaccination against viral infections, such as mumps and measles can be an added protection. Besides, routine hearing tests to detect early signs of ear infection and hearing loss and regular check-ups with an audiologist can help identify potential issues before they develop into more serious conditions,” he added.
(With inputs from Anna Jose @ Kochi and Rishita Khanna @ Bengaluru)