A 63-year-old man presented with a 4-year history of insidious onset and gradual progression of visual symptoms consisting of difficulty with locating objects within a complex visual scene (unable to see things "right in front of him," especially with clutter), impaired navigation while driving, and inability to perform complex motor tasks under visual guidance (ie, unloading the dishwasher). He subsequently developed alexia, agraphia, and acalculia. He was diagnosed as having a right homonymous hemianopsia by a neuroophthalmologist after he was hit by a truck from the right side while riding a bicycle. He later hit a parked car on his right while driving. His memory in daily life was intact. Within the first year of symptom onset, he developed mild language impairment characterized by word finding difficulty, anomia, and eventually mild comprehension deficits with intact repetition and speech production, consistent with transcortical sensory aphasia.His initial neurological examination findings were significant only for a right homonymous hemianopsia, with a notable absence of parkinsonism or asymmetric motor findings. There was no contributory medical history or systemic symptoms.His father developed dementia at age 52 years and died at age 57. The clinical diagnosis was Alzheimer disease (AD), but no autopsy was performed. There was no other significant family history including no history of Parkinson disease or amyotrophic lateral sclerosis.Neuropsychological testing performed 4 years after symptom onset revealed relatively intact memory function with impairments in visuospatial processing including impaired performance on Wechsler Adult Intelligence Scale, Third Edition Matrix Reasoning and clock drawing. There was also evidence of impaired phonemic fluency and word retrieval with intact semantic memory. Subsequent neurological examination findings revealed Bálint syndrome (simultanagnosia, oculomotor apraxia, and optic ataxia) with transcortical sensory aphasia, bilateral limb apraxia (right>left) with cortical sensory loss, and asymmetric rigidity of the right arm and leg.