Final answer:
The symptoms of vertigo, vomiting, nystagmus, and clumsiness with the right arm suggest a lesion in the cerebellum or brainstem affecting balance and coordination. The presence of muscle weakness and impaired balance further supports cerebellar dysfunction. Specific neurological tests can help in locating the lesion and evaluating the extent of any deficits.
Step-by-step explanation:
The symptoms described - vertigo, vomiting, nystagmus, clumsiness with the right arm - could be associated with a lesion in the brain affecting areas that control balance, coordination, and motor functions. Considering the gradual onset, one area that may be responsible is the cerebellum, especially the lateral regions which are involved in the control of appendicular musculature. The presence of nystagmus and vertigo suggests a possible issue with vestibular function, which is often associated with inner ear or brainstem problems, but the clumsiness and loss of coordination, particularly on one side, further points towards cerebellar involvement.
If these symptoms were accompanied by muscle weakness, difficulty moving, and an impaired ability to maintain balance, as described in the cases presented, it would support the suspicion of cerebellar dysfunction. The description of subtests that check for the presence of tremor, rebound response, and proprioceptive feedback adjustments also point toward cerebellar evaluation. Such tests help in assessing the integrity of the connections between the cerebellum, the red nucleus, and the descending motor pathways.
Additional symptoms described, such as difficulty swallowing, double vision, or ascending muscle weakness, may point to more diffuse neurological involvement, possibly indicating a condition like a brainstem stroke or other central nervous system pathologies.