Jens Denmark wrote:

http://www.netdoctor.co.uk/hilaryjones/secondopinion/cjd.htm
In humans it is a dementia characterised by the appearance of holes in the
brain tissue resembling a sponge, hence the term 'spongiform
encephalopathy'.  vCJD is an incurable illness lasting about 14 months.

http://jnm.snmjournals.org/cgi/content/abstract/36/4/616
SPECT with 99mTc-HMPAO was performed on a 65-yr-old patient with
Creutzfeld-Jacob disease. Cerebral blood flow was heterogeneously
decreased throughout the brain, differing from the pattern observed in
other common types of dementia. These results suggest that HMPAO-SPECT may
provide useful information in the differential diagnosis of dementia,
specifically when Creutzfeld-Jacob disease is suspected.

http://www.findarticles.com/p/articles/mi_m0999/is_7182_318/ai_61483016
Discussions about tonsillar biopsy vs brain biopsy (and the risks)

Some of my questions would be:
What's the problem with urinating? (loss of bladder control?)
What's his age?
What has been ruled out? I don't know what those tests he had done, ruled
out.  Nor what bloodwork he's had done.

Seems to me, if the above is true, and your father's been having these
symptoms for 4 years, they should be seeing the "characteristic holes in
the brain tissue resembling a sponge" (but I'm not a doctor and perhaps
that website isn't totally accurate - to what is currenly known).

Also seems to me that what you describe could fit a number of things,
including B12 deficiency.

There's a "Evaluation of neuromuscular disease: Guidelines" section here
http://www.neuro.wustl.edu/neuromuscular/alfindex.htm

If your father's relatively young, I'd be looking at his reports and
noting what's been ruled out and going from there, possibly getting a
second opinion.

I'm not a doctor, but I think sometimes doctors over-rely on scans to try
and figure things out, instead of having a round-table and tossing ideas
out to each other and/or there may be more clues that only the family or
those who live with him may be able to help them with.

If you have more information, I'll watch for your posts.
J

COMMENT:

The only really definitive diagnosis must be made by brain biopsy.

However, a PET scan of the brain will reveal a pattern of severe
cortical hypometabolism sparing the rear lobes, which can hardly be
anything else other than Alzheimer's or CJD. At that point, it won't
matter which it is.

I imagine you haven't gotten a PET scan because you live in nice
socialized medicine country, or else are in some nice HMO. But it
hasn't saved you any money, because you've gotten 2 MRIs and a CT,
which have told you nothing. One MRI and one PET is what you needed,
and the price for the combo is about the same. Lack of PET or at least
SPECT scans for dementing illness, while people burn money with
useless MRIs or even CTs, is a medical scandal. Among many.

SBH