The link between CRPS, Chronic Pain and hearing related problems

Tinnitus

Tinnitus sufferers hear ‘phantom’ sounds. Often described as whooshing, hissing, ringing or roaring, the sounds are phantom because although the brain perceives the sound, no external sound is actually there. Variable from person to person, tinnitus can be of high or low pitch, loud or very soft and is often, but not always, associated with hearing loss.

I speak with a little experience as I suffer from tinnitus in my left ear, which in my case is associated with hearing loss. I experience a soft hissing sound which occasionally changes to a high-pitched ringing. I am very fortunate in that it is not overly intrusive and much of the time the distractions of daily life are sufficient to divert my attention from it. Not everybody is so lucky.

The cause of tinnitus is not entirely understood, but it is not in itself a disease, but rather associated as a symptom of a number of underlying conditions including CRPS and other chronic pain conditions. In fact, the number of people with chronic pain who also suffer tinnitus is surprisingly high and a link between the conditions has been suspected for many years.

More recently, advances in brain imaging techniques have now shown structural and functional changes in areas of the brain common to both conditions. Whilst of no immediate benefit to sufferers, this better understanding of the common underlying cause of the conditions may eventually pave the way for preventative action and treatment. Encouragingly, unlike so many aspects of chronic pain, this is currently an active area of research.

Phonophobia

However, tinnitus is not the only hearing related condition associated with CRPS. Phonophobia, which is also known as hyperacusis, is very common among people suffering CRPS-related dystonia. Dystonia is a movement disorder which results in uncontrollable muscle spasms and contractions in one or more parts of the body. It is one of a number of motor symptoms associated with CRPS.

Phonophobia is a debilitating condition where sufferers develop a hugely increased sensitivity and intolerance to normal everyday sounds, including often their own voice. In most cases both ears are affected.

In one study, the incidence of phonophobia among those suffering CRPS-related dystonia was 38%, compared to 2% in the general population.

Research has so far identified no direct link between phonophobia and CRPS in general, only with those suffering associated dystonia. The reason for this link is not clearly understood, but one theory is that phonophobia in this group is the result of the spreading of central sensitisation to the auditory nerves.