The process is sort of similar to applying for VAC’s caregiver benefit. You have to show that you have significant impact to at least 1 or 2 activities of daily living... but unlike the caregiver benefit... with the DST you can use cumulative injury impacts. If your multiple impairments add up to a disability that affects you 90% of time performing tasks of daily living, then you will get the tax credit.
You are unlikely to get it just for hearing loss unless that impairment has rendered you legally deaf.
I was able to qualify under the cumulative. I have a 50% hearing loss with tinnitus, a TBI / brain injury, plus PTSD. I was able to medically demonstrate how these impairments impact ADLs as set out by service Canada.
If you have other injuries or medical conditions... you will have more success applying under cumulative. I prepared all the supporting documentation and gave this to my doctor to complete the form and send off. I was approved on my 1st attempt.
Since I was under 50 when I applied, I also qualified for the registered Disability savings plan. This can be backdated up to 10 years as the benefit becomes affective the date of injury or diagnosis. You can catch up to $10,500 of grant money a year (which takes 3 years to catch up provided you don’t turn 50). I was able to use 2 of those years as I was 47 when I got approved. I was injured at age 39. I missed out on my last few years of grant money but my income was high enough in those years, that I did not qualify for the full amounts... so there is a huge impact to getting this approved... onto just the $8000 plus in tax free earnings from the credit.
To get the Disability Tax Credit you complete the identification portion on the first page of the Canada Revenue Agency's form. If your income is lower, you should indicate who the Credit can be transferred to - often a spouse, parent or sibling that is providing care. You should also tick the box to have previous Income Tax Returns reviewed and adjusted, as the Credit can be backdated.
The form then goes to a medical practitioner (may not necessarily be a doctor - check the list at CRA). They complete the form, detailing the extent of the disability, and how it interferes with common, daily living, including the date of the onset of the condition.
Once signed by the medical practitioner, the form is sent to CRA (it can be scanned and sent electronically with CRA MyAccount). CRA reviews the application, and decides if the disability meets their criteria. This may take up to 6 months for a decision.