This patient’s main problem is her incoordination and unsteadiness which has been progressive and chronic. She has a positive family history which suggests a hereditary etiology. The most likely diagnosis is one of the spinocerebellar ataxias.

Her principle findings on neurological examination are those of incoordination and scanning dysarthria.

Her other finding is hyperreflexia and ankle clonus which suggest bilateral corticospinal tract or upper motor neuron degeneration. If the patient had had cerebellar dysfunction without any upper motor neuron dysfunction, then she would have had hypotonia with pendular reflexes. On plantar reflexes her toes don’t move either up or down so this finding is inconclusive. The upper motor neuron could be damaged anywhere from it’s origin to its final destination but with the cerebellar dysfunction one would look closely at the infratentorial level such as in the pons for localization of the lesion.