I never liked rock music very much so I didn't spend time in the bars where live bands broke the sound barrier every Friday and Sat night. I didn't go too Woodstock or any other big loud concerts because I didn't like crowds. I prefered jazz or classical where the sound wasn't cranked.
In the 1970's I experienced some assaults on my hearing from firing guns in and out of cars and buildings. I also joined my wife in target practice but shunned the earmuffs.
In the 1980's I was a contractor and used power tools, sand blasters, jack hammers and every hearing-damaging power tool known to man. I was aware that exposing myself to such high noise levels could be damaging to my hearing, We still had my wife's firing range earmuffs sitting on a shelf. I just didn't realize what a difference that might make.
I also didn't realize I was going to get Parkinson's. I don't know if having Parkinson's contributes to my hearing loss which is primarily in my left ear, and so far that's the side of my body that has been affected by PD. Most PD doctors and patients haven't thought that hearing loss can be caused by PD.
My hearing loss has been helped by wearing a hearing aid rather than turning up the volume. I do have problems with specific registers of sounds.
Much recent attention has also been to hearing loss and the aging process. A new study authored by Kelly C Harris at Medical University of SC announced in Health Day News the finding of the small portion of the auditory cortex reduced in size in older people wit hearing loss. Otolaryngalogist Robert D Frisina commented that he felt the study was promising because it had located evidence that hearing loss can go on in the grey matter of the brain where the neural processing takes place.
Research at Baylor University showed that while patients with Essential Tremor have a much greater rate of hearing loss than the general population, Parkinson's Disease patients don't appear to have the same losses. But there is ongoing recent research into synaptic proteins called synucleins (alpha, beta and gamma) that are involved in the transmission of nerve impulses in the cochlea of the ear. The cochlea contains the hair-like cells that vibrate in response to sound. The cochlea also has neurons that transmit those impulses to the auditory nerve connected to the brain.
Alpha synuclein has been cited as being involved or causative in Parkinson's disease Lewy bodies. This research will probably show whether there is a connection between hearing loss and Parkinson's.
By the way: I would be interested in hearing from anyone with Parkinson's disease who also has hearing loss. Or from carers whose PDers have a hearing loss.
Note: Check the Comments section for some additional Hearing Loss information.
Addendum: One connection to my hearing loss could be aspirin use although very small it is daily and that has been associated with hearing loss for decades. I simply do not recall when my hearing loss began. Was it before or after the aspirin use for my heart?