Chapter 32 - Functional auditory disorders
Introduction
This chapter outlines the disparate collection of auditory symptoms that can be considered to have a functional basis, at least in some cases. They transcend the disciplines of audiology, otorhinolaryngology, neurology, and psychiatry. Many of these conditions owe their origin to measurably abnormal peripheral sensory pathology or brain network activity, but their pathological impact is often due, at least in part, to overamplification of the salience of these phenomena.
Some of the conditions we describe, such as nonorganic hearing loss (NOHL), appear to affect a similar demographic and are amenable to similar psychological interventions to those functional disorders affecting motor or somatosensory systems that are commonly encountered in neurology clinics. Others, such as musical hallucination (MH), affect strikingly different population groups. As in those functional disorders affecting motor and sensory symptoms, it has only been in relatively recent years that we have come to recognize these conditions as truly disabling.
Section snippets
Definition
The situation in which patients may behave as if they have a significant hearing loss, both in general communication and on pure-tone audiometry, that is not borne out by specialized or objective testing, has a varied terminology. The descriptors malingering and feigning have been used clinically, possibly deriving from early reports of such behavior in wartime (Peck, 2012), and assume intentionality. The term psychogenic hearing loss makes an assumption that this is an exclusively
Definition
Auditory processing disorder (APD) encompasses a range of developmental and acquired disorders that affect auditory analysis and cannot be directly explained by structural pathology in the brain or cochlea or generalized cognitive deficit. Patients typically have normal auditory threshold sensitivity but have difficulty identifying speech (Keith, 2000) and/or nonspeech sounds (Rosen, 2005, Moore, 2006). The usual presenting complaint is an impaired ability to hear speech in background noise in
Definition
Tinnitus is a common symptom that is surprisingly difficult to define unambiguously. One regularly used definition is that tinnitus is the conscious perception of an auditory sensation in the absence of a corresponding external stimulus. This definition could include the auditory hallucinations of psychotic illness but in practice these are excluded. Other symptoms that comply with this definition and are sometimes seen as subtypes of tinnitus include musical hallucination (see below) and
Definition
Hallucination is the experience of a percept without a causal external stimulus. MH is therefore more than simply having a tune “stuck in your head” (an earworm), as it must have a compelling sense of reality. Indeed, patients commonly present to our services having first erroneously complained to police or local council services about their neighbors’ antisocial music playing, and some still believe the source to be external when assessed in clinic. MH is typically experienced as short
Definition
A small number of individuals have a persistent complaint of low-frequency noise (LFN) in their environment (usually the home), causing them severe physical and emotional distress. In comparison with patients with tinnitus, those with LFN complaint are insistent that the source is external rather than internal. Complainants tend to describe humming or rumbling, often accompanied by a feeling of pressure on the ears or vibration in the body – a common descriptor would be that of a “distant
Definition
Disorders of sound tolerance fall into two categories: dislike of sound above a certain intensity and dislike of particular sounds irrespective of their level. Terminology is confusing and still developing. Hyperacusis is a word used both as a blanket term to cover all types of impaired sound tolerance and to define a specific subtype. When used in the specific instance, hyperacusis refers to a dislike of all sounds above a certain level. Recruitment is a condition seen in association with
Definition
Misophonia is a disorder of the emotional processing of specific sounds, and can be literally translated as “hatred of sound” (Jastreboff and Jastreboff, 2001). Background sounds that would be generally described as perhaps mildly irritating, such as eating, noisy breathing, and typing, produce a strong sense of anger, and either aggressive or aversive behavior in sufferers (Schroder et al., 2013). This effect is distinguished from hyperacusis in that it is restricted to particular sounds,
Definition
Acoustic shock (also known as acoustic shock syndrome or acoustic shock disorder) describes a group of symptoms seen in people who have been exposed to sudden unexpected sounds. Initially recognized in people working in call centers using headsets, the symptom cluster has also been seen following exposure to a variety of other sound sources, particularly when the causative sound is generated close to the ear. The commonest symptom reported is pain in or close to the ear, followed by tinnitus,
Conclusion
There are a number of auditory symptoms that appear to have a functional component, some of which affect similar populations to those with functional neurological symptoms, whilst others affect very specific populations (notably MH and misophonia). Understanding in this area is emergent, and treatments are in many cases pragmatic and rudimentary, needing more work to be done in integrating insights from behavioral and cognitive psychology to auditory neuroscience. The audiology literature has
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