Clinical and neuroimaging features of corticobasal degeneration

Case presentation: Case 1: 81-year-old man started 3 years ago with rigidity in right lower limb leading to progressive impairment of walking with falls within 6 months and wheelchair bound in 1 year. Later he also presented rigidity of right upper limb. Concomitantly, he presented cognitive impairment and bradyphrenia. Neurological exam: right side bradykinesia, global rigidity, slow velocity of vertical saccades and involuntary elevation of the right arm (alien limb phenomenon). MRI: bilateral hippocampal atrophy. Case 2: 59-year-old woman started at the age of 54 memory impairment, executive dysfunction and motor apraxia. Physical exam: gait apraxia, global rigidity, hyperreflexia with Babinski and Hoffman signs in the right side, resting tremor in the right upper limb, polyminimyoclonus, severely cognitive impairment with global aphasia, slow velocity of vertical saccades and right alien limb phenomenon. MRI: asymmetric frontoparietal atrophy, well-marked on the left. Case 3: 58-year-old woman started with dyscalculia at 54 years, evolving with progressive aphasia, cognitive impairment and gait apraxia. Neurological exam: gait apraxia, global rigidity, myoclonus, dystonic posture of the trunk and upper limbs and severe cognitive impairment. MRI: asymmetric frontoparietal and hippocampal atrophy. Case 4: 68-year-old woman presented with gait impairment and postural instability. The symptoms started at the age of 65 with dystonic movement of the right hand evolving to ipsilateral tremor and motor apraxia. Physical exam: parkinsonian gait, myoclonus, motor apraxia, global aphasia, dysphagia, right alien limb phenomenon. MRI: global parenchymal atrophy, worse on left frontoparietal cortex. Discussion: Corticobasal degeneration (DCB) is a rare cause of atypical parkinsonism (1). The terms “corticobasal syndrome” (CBS) and “corticobasal degeneration” (CBD) represent distinct conditions. The former denotes the clinical phenotype, whereas CBD can only be confirmed by postmortem anatomopathological analysis (2). Classically, motor symptoms occur asymmetrically and include akinetic-rigid parkinsonism, dystonia, myoclonus and the alien limb phenomenon. Cognitive symptoms include apraxia, aphasia, cortical sensory deficits (2). In neuroimaging, magnetic resonance imaging typically reveals asymmetric cortical atrophy, predominating on the posterior frontal and parietal cortex (3). However, this pattern is observed around 50% of cases, depending mainly on disease stage. Final comments: In this report, we present four cases of CBS/CBD, through its clinical evolution with motor and cognitive findings, describing aspects of neuroimaging. The definition of CBD is only possible by pathological analysis, but neuroimaging could be a useful tool for differential diagnosis.