Progressive supranuclear palsy with predominant frontal presentation exhibiting progressive nonfluent aphasia due to crossed aphasia

Progressive supranuclear palsy (PSP) with predominant frontal presentation (PSP-F) is a clinical phenotype of PSP that is characterized by frontal cognitive impairment and behavioral changes. Here, we report on a patient with pathologically diagnosed PSP-F in whom we were able to observe temporal changes of the clinical manifestations. A 77-year-old right-handed man developed progressive nonfluent aphasia (PNFA) at the age of 69 years, festinating gait, and clumsiness of his left arm at age 75, disinhibition at age 76, and unprovoked falls at age 77. Neurological examination at age 77 revealed limb-kinetic apraxia of the left upper and lower limbs, rigidity, cortical sensory loss, and vertical supranuclear gaze palsy. According to the Movement Disorder Society clinical diagnostic criteria for PSP, his clinical manifestations shifted from suggestive PSP with predominant speech/language disorder to probable PSP-F over nine years. Cerebral atrophy on brain magnetic resonance imaging and decreased accumulation of Tc-99m-ECD on cerebral blood flow single-photon emission computed tomography were noted with right side predominance. Pathologically, 4-repeat tau-immunoreactive globose-type neurofibrillary tangles, coiled bodies, tufted astrocytes, and neuropil threads were observed predominantly in the frontal cortex. Tau pathology of the substantia nigra, locus coeruleus and subthalamic nucleus was mild. These findings suggested that localized tau pathology involving the pars opercularis extended to the precentral gyrus, prefrontal cortex, and brainstem. This case report demonstrates that PSP-F can present as a PNFA due to crossed aphasia.