She could ask her GP whether there is any tinnitus retraining offered locally as that might help. CBT is the other route she ought to pursue and it might be available on the NHS but if not would be worth paying for privately. Or the sort of aversion therapy that hypnotherapists do for people who can't stand the sight of spiders/ feathers/whatever. Again likely to have to pay for that (and there are some charlatans in that field so a recommendation from a friend probably best). But a referral to someone who specialises in abnormal auditory response would probably be your best bet.
I have the book Functional Neurologic Disorders, and for people who are averse to hearing noises, wearing headphones with background noise or music can help. The patient needs to adjust to hearing sound so that she does not have a bad reaction every time that she hears normal noise.
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