In my last post I described several differences between SPD and misophonia that makes them distinctly different conditions. But the biggest difference is between SPD stimuli and misophonia trigger stimuli. The two conditions have, by the basic definitions of the disorders, mutually exclusive trigger stimuli.
Auditory Trigger Stimuli: SPD triggers are volume based. Loud sounds such as a vacuum cleaner, toilet, loud toy, fireworks, etc. Misophonia triggers are content related and soft sounds. Examples include the sound of someone breathing, father chewing, soft sound of music through walls, typing, sniffing, etc. Therefore, auditory triggers for SPD and misophonia are almost exactly the opposite. SPD triggers are loud and do not depend on the content or source of the sound. Misophonia triggers are soft sounds which must have specific content/meaning. This alone indicates that SPD and misophonia are defined as distinctively different conditions.
Visual Trigger Stimuli: As with auditory triggers, visual triggers are based on the intensity of the trigger for SPD vs. the specific image for misophonia. SPD triggers include bright lights and fluorescent lights. Misophonia visual triggers include such things as seeing a person chew gum, bouncing their leg, or pointing with one finger. Again, misophonia triggers are low intensity with specific meaning/content/context, and SPD triggers are high intensity.
Tactile Trigger Stimuli: SPD sufferers are often very sensitive to touch, such as tight shoes, clothes tags, being touched by another person, or certain textures. Tactile sensitivity is very common with SPD, but tactile triggers are almost non-existent for misophonia.
It is just my guess that the individuals who are claiming that misophonia is a form of SPD are well-meaning individuals who are trying to get more research and public awareness for SPD. I think they truly believe these conditions are related. There was even a peer review journal article by academic researchers (Sensory Intolerance: Latent Structure and Psychopathologic Correlates by Taylor, et al., 2014), which called misophonia “auditory sensory intolerance” and suggested it should be a form of SPD. But in their SPD study survey, participants were asked to rate their tactile intolerance by responding to the statement, “I am very bothered by certain tactile sensations, such as clothing textures or tightness; substances that feel sticky, greasy, or wet, or activities like haircuts or cutting my nails.” Auditory intolerance was assessed by the item, “I am very bothered by certain auditory sensations, such as the sound of alarms, sirens, appliances, or background noises like people talking or ticking clocks.” Clearly these measures would not be used for assessment of severity of misophonia.
When we reviewed this journal article while preparing the manuscript of Misophonia Phenomenology, Impact, and Clinical Correlates, we noted that the Taylor article “investigated sensory intolerance to tactile stimuli and to loud or constant auditory stimuli.” We concluded that “this definition is inconsistent with the description of typical trigger sounds in the misophonia literature (Edelstein et al., 2013; Jasterboff & Jasterboff, 2014; Schröder et al., 2013).
Comparing misophonia and SPD is like comparing influenza and malaria. Symptomatically, both cause high fever and make you feel horrible. But one is a viral infection and the other bacterial. The treatment is completely different.
My heart goes out to anyone who has either of these conditions, and especially to those who are suffering from both. But please, for the sake of both SPD and misophonia research, management, and treatment, let’s be clear that they are distinctively different conditions. Misophonia can learn from SPD research, and SPD can learn from misophonia research, but I do not consider them to be forms of a larger, similar condition of sensory intolerance. I wish success and progress to those researching SPD, and we (and others) will push forward with research on misophonia. May we all be successful in our valiant efforts to help those with either or both of these conditions.