Autistic individuals often complain of suffering from hearing hypersensitivity (hyperacusis); meaning, an intolerance to sounds in their everyday living environment. Although neurotypicals learn to tune out the hum of a computer or the high-pitched whir of a dentist’s drill, such sounds rarely go unnoticed by people with autism. Moreover, some sounds, like the ringing of a school bell, may be especially painful or even torturous to them. It is therefore unsurprising that, over time, some of these sounds may trigger emotional reactions. In this regard, the repeated nature of the acoustic assault resembles a posttraumatic disorder (PTSD); a terrifying experience elicited or triggered by sound. It is not a coincidence that therapeutic attempts using music for healing PTSD symptoms have also been used in autism to improve areas such as sensory issues, joint attention, and behaviors.
The unwarranted fear of sounds is called phonophobia. In people with migraines phonophobia is sometimes accompanied by sensitivity to light (photophobia). Retreating to a dark, quiet room and sleeping have been found to alleviate the severe headaches. In a majority of cases, phonophobia is an anxiety disorder, rather than a hearing impairment. If anything, patients with phonophobia perceive sounds as being much louder than other people around them. With time, phonophobia overwhelms the sufferer who will then use their hands to cover their ears in an attempt to block out the noise. In autism, this behavior is usually accompanied by repetitive behaviors (e.g., rocking) as a way of calming down.
Hyperacusis and phonophobia are often confused. However, phonophobia is a persistent fear of sound while hyperacusis is an increased sensitivity to certain frequencies and volumes of sound in levels that would not trouble a normal individual. This sensory sensitivity is commonly noted early in the life (3-4 years of age) and is not related to hearing impairment. It is commonly seen in neurodevelopmental conditions, predominantly in autism (Myne and Kennedy, 2018). This debilitating disorder usually occurs along, and is worsened by, tinnitus. Other comorbid conditions to hyperacusis include Bell’s facial palsy, fibromyalgia, multiple chemical sensitivity, and Williams syndrome (Paulin et al., 2016).
Tinnitus is an acute or chronic perception of ringing, hissing, clicking or whistling in the ears that occurs in the absence of an external sound source. It is a common problem affecting close to 15 to 20% of the general population (49 to 66 million people according to 2019 Census estimates). It rises in prevalence with aging peaking in people between 60 to 69 years of age. According to one study, tinnitus may be seen in as many as 35% of high functioning autistic individuals (Danesh et al., 2015). It may be that high functioning autistic individuals may find it easier to interpret and communicate their health-related problems thus inflating their prevalence as compared to lower functioning individuals.
Tinnitus is defined as a symptom, a reported self-complaint that provides evidence for an underlying disease. There are many causes of tinnitus including prolonged exposure to loud sounds (causing loss of hair cells in the cochlea, head and neck trauma, use of antibiotics, allergies, and temporomandibular joint (TMJ) disorders. Most people become accustomed to tinnitus and learn to tune it out. Treatment involves eliminating any underlying disorder including, in some cases, anxiety and/or depression. Other interventions for tinnitus include magnesium supplementation, sound therapy, and headphones. Noise attenuating headphones in particular have proven useful in attenuating both the injurious sounds and the attendant sympathetic activation (Pfeiffer et al., 2019).
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