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In the not-too-distant future, patients with multiple sclerosis (MS) may simply strap on an iPad to complete their balance and walking tests, without the need for a technician.

The test results would be automatically uploaded to a clinical or research database, eliminating the chance of human error.

And patients may be doing the tests in the comfort of their own home, eliminating the need to visit a clinic, a boon to those living in rural areas or with mobility issues..... Read More - http://www.ms-uk.org/technology

Wow, when you strip the hype away from this is should be more like wow.
This really looks like big business staking a claim; either in support of a patent, or to deny a competitor a patent. Not on the iPad, of course, but on the dedicated device that attaches to it. The performance figures quoted look impressive, but in reality they are not so hot.
Read the release, and see the comparison between the standard tests and those re-written for the iPad. The words are:
"the correlations were mostly above .9 ..."
OK, so a correlation of 0.9 means that the amount of variance accounted for is 0.9 squared - or 0.81. That is almost one chance in 5 of being wrong. Assume that one of the correlations that was not in the "mostly" category was way down at 0.85 - that drops the explained variance down to 0.72. That is one chance in 31/2.
Now, you have to look at two more things:
- The iPad tests could actually be better - and the release does suggest this - but it also suggests that the question of test validity has yet to be resolved.
- This will do away with the need for a technician. This could be a good thing from a cost point of view. If the test/re-test reliability comes out better than the technician it could be a very good thing. The iPad should be totally impartial, and that is a very good thing indeed.
But, taken overall, it still looks like a press release aimed at staking a claim to be first.
Geoff