The Impact of Deafness on Hallucinations and Delusions

Psychosis can be a debilitating symptom of various mental illnesses, causing hallucinations and delusions that interfere with a person’s day-to-day living and quality of life. For those with hearing impairment, hallucinations and delusions can create even greater disadvantage.

Studies have shown that hearing impairment increases the risk of psychosis. For example, hearing loss at an early age has been associated with an increased risk of developing schizophrenia at a later age.¹ One study involving individuals who had experience of hallucinations revealed that 16.2% of participants with impaired hearing hallucinated in the last 4 weeks. However, only 5.8% of participants without impaired hearing hallucinated within the same period.²

While researchers have documented experiences of hallucinations and delusions among hearing-impaired groups, Dan Blazer, MD, MPH, PhD, JP Gibbons Professor Emeritus of Psychiatry and Behavioral Sciences at Duke University Medical Center, says, “We actually know very little about psychoses in the deaf.”

So, how are hallucinations and delusions shaped by the experience of deafness? Dr Blazer, who recently published a review titled “The Silent Risk for Psychiatric Disorders in Late Life,”³ says, “When we have problems hearing, we are more apt to misinterpret our environment. The social environment may then appear more threatening and less understandable. We begin to fill in the gaps ourselves.”

However, he emphasizes that while this mechanism certainly leads to delusions, it doesn’t specifically lead to hallucinations. Hallucinations relate to an inability to distinguish between conscious sensory experiences and memory-based sensory perceptions. Delusions, on the other hand, occur when a person holds onto inaccurate or false beliefs despite being shown evidence to contradict those beliefs. For example, researchers have reported that people with impaired hearing have experiences of hearing the voice of a loved one who has passed away (hallucination) or believing that other people are speaking ill of them (delusion).¹

In Dr Blazer’s review, the focus was on psychosis risk among the elderly. The prevalence of hearing loss increases as people age. The World Health Organization estimates that 5% of the world’s population has some form of hearing loss. In the United States, 75% of people aged ≥70 years have hearing impairment.⁴ With an aging American population, Dr Blazer considers hearing loss a silent epidemic linked with delusions among the elderly. Indeed, other studies have also shown that elderly individuals with impaired hearing are at increased risk of developing delirium.⁵

Factors Affecting the Content and Topography of Hallucinations and Delusions

Researchers typically characterize hallucinations and delusions according to content. Studies reveal that the content of auditory hallucinations among hearing-impaired persons varies greatly. Their hallucinations can consist of voices, music, telephone rings, or doorbell sounds.² Blazer adds that auditory hallucinations can range from ringing sounds similar to tinnitus to frank delusions of being verbally criticized by another person.

Hallucinations and delusions are also typically defined by topographical characteristics. When asked about the topography of hallucinations and delusions among deaf adults diagnosed with psychosis, Dr Blazer says, “After all these years, we actually don’t have an answer to this.” So far, studies provide limited information on a few topographical components such as frequency and loudness. For example, one study showed that auditory hallucinations increased as the severity of hearing loss increased. More than 16% of participants with hearing loss experienced hallucinations in the previous month. However, among the participants with the most severe hearing impairment, 24% had auditory hallucinations in the same time frame.² “In other words, the sounds heard, or lack of sounds, can lead to a wide range of ‘fill-in-the-blank’ moments,” Dr Blazer says.

Misinterpretations by Clinicians Who Can Hear

An improved understanding of the content and topography of hallucinations among individuals who are deaf is particularly important since clinicians have made some misinterpretations with regard to deaf people’s experiences of hallucinations.⁶ For instance, individuals who have been completely deaf since birth have been reported as having “heard” voice hallucinations. However, recent studies have shown that the confusion emerges from the complexity of understanding the unique experience of a deaf person. People who have been completely deaf since birth cannot experience true auditory hallucinations. Rather, they experience visual or physical hallucinations such as moving lips, sign language movements, body motions, and facial expressions that they interpret as an expression of the voice.⁶ The loss in translation happens when deaf people need to borrow sound-related terminology or hand gestures to communicate with interpreters or psychiatrists who can hear. In effect, hearing people may make false conclusions when learning about the experiences of hallucinations among deaf people.

The Healthcare Professionals’ Role in the Clinical Setting

Misinterpretations in our understanding of psychotic experiences among those with impaired hearing illustrate a need for improved care for this group. Psychiatrists may need to widen the range of patient experience that they currently embed in interviews with deaf people and include diverse visual and physical characteristics of hallucinations and delusions.⁶ “The therapist should also be vigilant in terms of how well the patient can understand and communicate in a session,” Dr Blazer adds, as the ability to perform sign language or read lips may affect how precise a patient can correspond with a nondeaf healthcare professional.

Early diagnosis and treatment of hearing loss is also important to help prevent psychosis.¹ According to Dr Blazer, “The mental health worker who is working with a patient with hearing loss should determine if more could be done to improve the patient’s hearing. Recent information from an [ears, nose, and throat] specialist or an audiologist can be of great benefit.” Furthermore, clinicians need to inquire about experiences of hallucinations and delusions among patients with impaired hearing to provide more timely care to the patient.⁶

Need for Further Research

Dr Blazer points out that new scientific papers have filled some of the knowledge gaps in the association between psychosis and hearing impairment. However, more data about this phenomenon and its confounding factors are needed. “First, it would be good to know whether improving hearing, such as with a good hearing aid or a cochlear implant, would decrease the risk of psychoses [for those who develop hearing loss in later life and for those who struggle with sign language and attempt to communicate verbally],” he says. “Second, we don’t have enough data on whether the use of antipsychotic medications among the deaf is less or more effective in treating psychoses than in those who hear adequately.”

More robust data on the topography and content of hallucinations and delusions can reveal how psychosis is shaped by experiences that are unique to those with a hearing impairment. Importantly, it can inform how psychosis in hearing-impaired groups can be more effectively prevented or treated.

References

1. Linszen M, Brouwer R, Heringa S, Sommer I. (2016). Increased risk of psychosis in patients with hearing impairment: review and meta-analyses. Neurosci Biobehav Rev. 2016;62:1-20.
2. Linszen M, Van Zanten G, Teuisse R, Brouwer R, Scheltens P, Sommer I. Auditory hallucinations in adults with hearing impairment: a large prevalence study [published online March 20, 2018]. Psychol Med.  doi.org/10.1017/S0033291718000594
3. Blazer D. Hearing loss the silent risk for psychiatric disorders in late life. Psychiatry Clin Neurosci J. 2018;41:19-27. 
4. Rooth M. The prevalence and impact of vision and hearing loss in the elderly. NC Med J. 2017;78(2):118-120. 
5. LaHue S, Liu V. Loud and clear: sensory impairment, delirium, and functional recovery in critical illness. Am J Respir Crit Care Med. 2016;194(3):252-253.
6. Anglemyer E, Crespi C. Misinterpretation of psychiatric illness in deaf patients: two case reports. Case Rep Psychiatry. 2018(3285153):1-4.