Parkinson's Disease

"I don’t see anything in the description suspicious for a CN V3 (mandibular nerve) injury (was there a sensory impairment on the right side? V3 carries sensory fibers to the lower 1/3 of the face) except the jaw droop at rest which may just be his posture. Tongue to right would be right XII and palate paresis with hypernasality would be X. Also you would have to figure out what type of lesion would selectively affect these nerves/brainstem nuclei on both sides of the patient.

The most likely explanation for your observations is the rigidity associated with parkinsonism. The inability to initiate motion is one property of rigidity in which both agonist muscles (those that perform the intended movement) and their antagonists (those that resist the intended movement) are activated at the same time the patient wants to move (antagonist inhibition is disrupted in parkinsonism). Of course a MRI of his brain would help you to sort this out because certainly, apraxia after an undiagnosed stroke could cause motor planning problems (but the same stroke should not cause the bilateral cranial nerve lower motor neuron pattern observations.

If rigidity it might help to ask the patient whether he notes any improvement in the inability to initiate movement shortly after taking his Parkinson medications. Some patients (probably about 25%) notice a distinct “on” phase after medications in which they move much more easily for a short time. In those cases we ask the attending or neurologist to consider whether trying timing the medication to precede the intended activity (eating) by one-half hour or so is not contraindicated.

This article is an interesting as it relates to treatment of Parkinsons patients by using a motor pre-cue.

Johnson, A. M., Vernon, P. A., Almeida, Q. J., Grantier, L. L., & Jog, M. S. (2003). A role of the basal ganglia in movement: the effect of precues on discrete bi-directional movements in Parkinson's disease. Motor Control., 7, 71-81."