Which finding is least likely in a patient with a parietal lobe infarct?

In a patient with a parietal lobe infarct, the least likely finding would be cortical deafness. This condition is typically associated with bilateral damage to the auditory pathways or the auditory cortex in the temporal lobes, not the parietal lobe. The parietal lobe is primarily responsible for processing sensory information, spatial awareness, and certain aspects of language and numerical cognition.

Homonymous hemianopia can occur with parietal infarcts if the lesion involves pathways that affect visual processing. Meanwhile, acalculia, which is the inability to perform mathematical calculations, can result from damage to areas in the parietal lobe involved in numerical processing. Expressive dysphasia, characterized by difficulties in speech production while comprehension remains intact, can occur if the parietal lobe infarct affects language-associated regions nearby, particularly in the dominant hemisphere.

In summary, since cortical deafness relates to the impairment of processing auditory information and is linked to areas outside the parietal lobe, it is least likely to be present in a patient with a parietal lobe infarct compared to the other listed findings.