In an attempt to discuss the impact of sensory hypersensitivity and PEM in ME, I can only speak for myself but for me there are two types of PEM. One is immediate and the other is delayed by 24 hours, to the hour usually suggesting a link to circadian rhythms.
Severity fluctuates for me so sometimes if I try to do something like hoover the front room or heaven forbid tidy the garden, the immediate PEM happens and causes a crash then I get 24hr PEM on top of that, other times I can push it a bit but dont crash yet I know the kind of exhaustion which spells trouble and means I will get PEM 24hrs later even if I dont crash completely in the short term.
Either way short term exertion contributes to both short and long term PEM and is very exhausting and I have to rest completely for three days to even begin to recover back to baseline. Exhaustion and fluctuation both seem to exacerbate my nervous system's hypersensitivity which, once I was finally diagnosed after ten years undiagnosed, I was glad to read the late Dr Paul Cheney had addressed as a feature of ME, in the context that it is also common in brain injuries as it is a natural response for the nervous system to upregulate itself in this way. I dont think people with normal nervous function can easily appreciate the pathological extent this can reach.
I have always been able to stay out of bed, at the cost of PEM, which I attribute to rowing training and learning to function beyond the pain barrier. Its a curious thing but when you push yourself beyond the pain barrier the brain starts shutting down unecessary processing and I remember one race finishing with what is described as gun barrel vision, where the perceived world is seen as though through a pipe or gunbarrel, seeming distant, further cognitive processing shut down.
During ten years undiagnosed I was often out on my feet, racking up PEM trying to do simple things like a bit of shopping and at such times my nervous system would collapse due to the fatigue and the inflammatory responses both types of PEM involve. During those times I could not understand the world around me properly and used to do things like walk into street furniture because I did not realise it was in my way. Surprisingly I could see it e.g. a lamp post but could not recognise it for what it was and walk around it!
Sensitivity to sound aka hyperacusis has always been a feature, very different from before onset, any little noise is disturbing and loud bangs shoot right through me and hit a nerve as it were and make me feel very angry. I have no control over this feeling but can suppress my impulse to respond aggressively, as though attacked and injured. I also found daylight too bright and painful after onset so I have learned to shield my eyes, lurk in shadows, wear shades and squint etc when before I adapted easily.
One undiagnosed experience I had which parallels the severe ME cases I have read about was when at one point I was so exhausted my referential system broke down completely. Perceptually I could not comprehend the nature of the sources of sounds or how they were related to me in my environment properly and had odd but lucid experiences like sitting on a bus and everyone on the bus was chatting but I perceived they were all chatting to me or about me. It felt like the cognitive filters which tell you "that is someone chatting to her friend over there and nothing to do with me" had simply collapsed and for some reason, possibly exhaustion as with gun barrel vision, my brain had shut them down. In the absence of filters all the noise in the world seemed to pour in to my core like a cognitive waterfall in flood and so I perceived them as though they were all directed at me which was itself very disturbing and even more exhausting, which is a vicious spiral of course. I knew things couldn't be as they appeared but that was how I percieved them, hence lucid but also deeply demoralising.
During that phase I experienced some very unpleasant phenomena for a while which are best decribed as a trip to hell, where every noise I heard was painful to hear, like the screech of a dinosaur in my ear, or a cosmos filled with fingernails scraping on blackboards. Any sound was screechingly painful and caused involuntary terror and overstimultion of my nervous system. This is the closest experience I have had to the descriptions by people with severe ME I have read.
Something else which is similar and more common is rigors which I get sometimes, where just a hint of cold air on my skin can cause me to feel as if I am freezing cold when I am not and to shake and clench my abdominal muscles in involuntary spasm due to the intense feeling of cold, so I can barely walk to get back inside or to somewhere very warm.
Attempting to interpret such experiences using my education in neurophysiology (mostly from
Prof Steve Simpson, who was a kind teacher, thanks Steve) as part of my zoology degree at Oxford (I was deeply fascinated by animal behaviour and how it evolves), I think all these kinds of experiences are similar in the way they result from sensory hypersensitivity due to neurological upregulation combined with the shut down of cognitive processing due to neurological exhaustion (exacerbated by neurological upregulation), leading to sensory inputs impacting the midbrain directly in a way they don't normally do, leading to immense pain. I think the problem with this is the great potential for spiralling exhaustion because of the strong neurological responses such hypersensitivity stimulates, which are themselves exhausting, leading to short term PEM and contributing to the backlog as it were of longer term PEM.
I hope this account makes sense and helps comprehension of these phenomena or at least a discussion of them and I fully understand my experiences may not be the same as other people who are more severe. But that is what happened to me FWIW. Importantly, since I was told to rest and pace by Westcare in Bristol before they joined Action For ME, the neurological/cognitive hellhole I was trying to function within has gradually improved the more I rested, though if I get exhausted or fluctuate downward due to infections etc these problems do come back again.
An appropriately educated psychologist ought to be able to understand all that from a neurophysiological perspective and respond appropriately, the question is whether they are trying to interpret their observations and accounts from patients using the right or the wrong models. The latter obviously leads to completely the wrong kind of response which makes everything worse.
