So, onset of disability is 1992 and no work since then, correct?

For you to get SSDI, you have to have 20 work credits in the 40 quarter period before your onset of disability. That roughly translates into 5 years of work in the 10 year period before you couldn't work any more. This is called insured status for disability. To be insured for retirement, you need 40 credits in your lifetime. For disability, you have to have a recent connection to work also. At some point, after you stop working, insured status can run out, like a car insurance policy lapsing for lack of payment of premiums. To get SSDI, you have to be found disabled but you also have to be found disabled before your date last insured.

If you stopped work in 1992 and have not worked since that date, your date last insured would be sometime before 1998. So, for you to get SSDI, you would have to prove, by medical evidence, that your medical condition was severe in 1997 and is still severe in 2009. That may be hard to do. It is not impossible if you had ongoing medical treatment for your condition that shows the extent of the problem. But without medical evidence dating back to 1997 or earlier, it may be impossible to prove that you were disabled back in 1992.

Now, for SSI, the public assistance program, you only have to prove you are disabled the day you file the claim and are expected to be disabled for the next 12 months. So, not working since 1992 won't affect the SSI claim. What will affect whether or not you can get SSI is how much income do you have, how much does your spouse have (if you live together), how much do you own, how much in the bank, what are your living arrangements.

You should complete the online disability report at socialsecurity.gov using 1992 as your onset date and schedule an appointment with your local office to file both an SSDI and an SSI claim before the end of April, so you don't lose any potential benefits. I think the SSDI is a long shot and I don't know enough about your finances to comment on the SSI, but this is the only way you'll know for sure whether or not you can get either one. Nothing to lose by filing a claim.