This is part 1 of a two part series.
Sometimes when I try to understand, my head spins misophonia. One of the most challenging areas for me has to do with auditory neurology, which is where I’m at because I’m less familiar with it than psychology. Most of us don’t know the neuroscience of hearing, and that hinders our ability to read the research. I had the opportunity to interview Dr. Prashant Prabhu, who clarified many of these issues for me. He has published more than 10 articles on misophonia over the past few years. His knowledge is a gold mine and his answers provide information that will help you read the research more easily. This article covers the neuroscience of hearing and in our next article we will discuss Dr. Prabhu’s study.
Jennifer Brown: Many people find it difficult to understand the difference between hearing disorders and neurological disorders (peripheral and central). Can you explain that? Based on your knowledge, can you say that we can rule out peripheral causes of misophonia?
Prashant Prabhu: I usually explain it like this: The peripheral auditory system includes the outer ear, middle ear, inner ear, and auditory nerve, while the central auditory system includes the neural pathways and areas of the brain that process sound beyond that point, including the brainstem and auditory cortex; nervous disease, in a broader sense, means that nervous system affect its structure or function. In misophonia, the available evidence does not point to a clear lesion of the peripheral ear as the primary cause, and work in our laboratory and others has found stronger evidence for abnormal activation and connectivity in higher cortical networks than in the ear itself.
In us auditory brainstem response studiesthe auditory pathway to the lower brainstem appeared intact in people with misophonia, and in our cochlear study, measures of linear, nonlinear, and efferent hearing were not significantly different from controls, suggesting that peripheral mechanisms are not major contributors. So I would say that we cannot completely rule out any subtle peripheral influence, but the current literature supports misophonia more as a disorder of central auditory, emotional, and autonomic processing than as a primary peripheral problem.
JB: Can you explain what is central auditory processing disorder?
PP: Central auditory processing disorder, or CAPD, refers to a problem with the way the central auditory nervous system (from the auditory nerve to the auditory cortex) processes, even when basic hearing sensitivity is normal. In simple terms, a person can hear sounds, but the brain has difficulty organizing, interpreting, or understanding them, especially in tasks that involve speech in sound, dichotic hearing, or transients. pattern recognition. In short, it is primarily a functional disorder in which the structure may be normal, but the processing of sound outside the auditory nerve to the auditory cortex is affected.
JB: Would you also explain what the “higher auditory centers” in the brain mean?
PP: “Higher auditory centers” simply means the areas of the brain that understand sound, mainly the auditory cortex. These areas do more than just detect sound; they help the brain notice, process, and feel what it hears. So in our papers, when we say that the higher auditory centers may change, we mean that the sound processing parts of the brain may work differently in people with misophonia.
JB: There is much debate about how to classify misophonia (neurological, neurophysiological, auditory, emotional, psychological). How would you categorize misophonia?
PP: In my opinion, misophonia is better classified as a neurophysiological condition with auditory, sensory and emotional components, rather than as a purely psychological or purely auditory/sensory disorder. I say this because our studies show altered cortical auditory processing, scalp topography, and impaired performance on cortical auditory processing tasks. At the same time, the findings also show that misophonia is not limited to sound processing, as emotional reactivity, attentionauditory and limbic interactions and even multisensory mechanisms appear to be involved. So, if I had to put it simply, I would say that misophonia is a neurophysiological disorder of reduced sound tolerance with important auditory and emotional features.
JB: Anecdotally, if you had to make a list of sounds common in hyperacusis and misophonia, what would it be?
PP: In hyperacusis, the types of noises that people often mention include vacuum cleaners, barking dogs, car engines, kitchen appliances, running water, clattering dishes, babies crying, bells or traffic noises (more so in countries like India) or even loud talking. These are usually not alarming because of who is making them, but because the sounds themselves are so intense.
In misophonia, the most commonly described sounds are chewing, smacking, swallowing, sniffing, breathing, clearing the throat, tapping, tapping, typing, or hissing. These triggers are often human-generated and can be heavily influenced by context, including who is making the sound and the situation in which it occurs.
