The main way to determine Dissemination in Time is to evaluate the behavior of the patient's symptoms. If you have had two or more distinct attacks (episodes of symptoms) then you have Dissemination in Time.
The only time you need to look at the McDonald Criteria is if you don't have enough clinical (symptoms and neuro exam abnormalities) data to prove dissemination in time or space THEN you can use MRI data for the evidence. That is the main usefulness for the McDonald Criteria. The group that formulated the McDonald Criteria (both the intitial and the revised) themselves stated this. You can use info from the MC to substitute if the patient is missing a second attack or if there is only evidence of one lesion - that is only evidence of one spot of damage in the CNS.
Your neuro should be paying more attention to the findings on the neuro exam. Here are the distinct "lesions" that I find from what you have told us:
1) Trigeminal Neuralgia - bilateral - This can only arrise from a lesion on the brainstem or along the Trigeminal nerve as it runs to the face. Since it is bilateral that probably means that you have two lesions on the brainstem or the nerve. Since it is in the same area, a neurologist would probably count this as "one location" of damage.
2) Clonus - This is the maximum amount of hyperreflexia. By definition, hyperreflexia is caused by a spinal cord lesion. So this is a separate area of damage from the brainstem.
3) Positive Hoffman's and assymetrical Babinski - This might be a separate lesion from the one(s) causing the hyper reflexes - I don't know. The fact that the Babinski is present only on one side is highly suggestive of MS.
4) If the tinnitus is related to MS then it is another separate lesion involving the brainstem, but the Cranial Nerve VIII - the Accoustic Nerve.
You fulfill Dissemination in Spave by virtue of #'s 1 and 2. Now, if you have had more than one attack, you fulfill Dissemination in Time. Period.
Remember, our neuro's should only be looking to the MRI for evidence for spread in time or space IF the evidence is lacking from our history (two or more attacks) or our neuro exam (abnormalities on exam or testing).
Also, remember that testing can provide evidence of lesions in other locations. The best example is a positive VEP showing damage to the optic nerve.
MS is STILL best assessed by LISTENING to the patient (noting all the features of attacks and symptoms), LOOKING at the patient with a very thorough neuro exam (noting the abnormalities and realizing that these abnormailties indicate areas of damage in the central nervous system) and THINKING!
If the patient has 2 or more attacks and 2 or more areas of damage, then the ONLY thing they need to look at the MRI for is consistent lesions. One or more consistent lesions is enough to nail the diagnosis.
So much of the time the McDonal Criteria are NEVER needed.
The two Health Pages that describe this best are the very long, but useful:
http://www.medhelp.org/health_pages/Multiple-Sclerosis/History-of-the-Diagnosis-of-MS/show/158?cid=36
http://www.medhelp.org/health_pages/Multiple-Sclerosis/Diagnosing-MS---The-McDonald-Criteria-revised-2005/show/370?cid=36
I hope this takes care of the confusion.
Quix