Is the pathology of corticobasal syndrome predictable in life?

Abstract

Corticobasal syndrome (CBS) has been associated with a heterogeneous spectrum of pathologies with an increasing number of reports of Alzheimer's type pathology. There is, however, no means of predicting pathology of CBS in vivo at present. We compared the clinical features of patients presenting with CBS who have either pathologic changes of classic corticobasal degeneration (CBD) or Alzheimer's disease (AD) at post-mortem to identify predictors of the specific pathological processes in life. Twelve patients with CBS were followed prospectively; six had AD and six had classic CBD neuropathology. After review of the presenting clinical features, we identified nine potential predictor variables, compared their frequency in the two groups, and performed a discriminant function analysis. Initial episodic memory complaints and poor performance on the combined orientation-memory subtest of the Addenbrooke's Cognitive Examination (ACE) reliably predicted AD pathology while varying combinations of early frontal-lobe type behavioral symptoms, nonfluent language disturbance, orobuccal apraxia, and utilization behavior predicted CBD pathology ante-mortem. CBS is frequently associated with Alzheimer's disease pathology. Early episodic memory impairment versus early behavioral symptomatology appears to best predict AD or CBD pathology in life.2009 Movement Disorder Society

Visuoperception test predicts pathologic diagnosis of Alzheimer disease in corticobasal syndrome

“…22 The CBS-AD group scored significantly lower on the orientation-memory subtest of the Mattis DRS-2 in primary and secondary analyses. Of note, patients with CBS-AD also perform worse on the orientationmemory subcomponent of the Addenbrooke's Cognitive Examination, 9 and a recent review of 42 CBS cases identified memory impairment as being associated with CBS-AD 11 (although the nature of this impairment was not precisely defined). It remains difficult to determine which aspect of memory may be impaired because of the inclusion of orientation in this scale.…”

“…Frequently, patients with CBS are found, postmortem, to have pathology of Alzheimer disease (CBS-AD), progressive supranuclear palsy (CBS-PSP), or other non-CBD pathologies. [3][4][5][6][7][8][9][10] Of the various pathologic substrates of CBS, AD is common, accounting for more than 20% of cases. 3,5,9,10 Antemortem diagnosis of CBS-AD is important, because patients may benefit from cholinesterase inhibitors or future AD-targeted treatments.…”

Corticobasal syndrome

“…5,8,9 For example, cortical Neurology.org/cp sensory loss and myoclonus, classically considered key features of CBD, have in fact been shown to be associated with either CBD or Alzheimer disease (AD) pathology. 7,10 While the motor syndrome of CBS is distinct from other neurodegenerative parkinsonian syndromes, there are few specific motor features that reliably predict underlying pathology.…”

“…One study suggested that episodic memory complaints may predict AD pathology in patients with CBS, and evidence for frontal lobe dysfunction (such as nonfluent language deficits and utilization behavior) may predict CBD. 10 However, others have not demonstrated distinct cognitive profiles in CBS cases with underlying AD vs CBD pathology. Alzheimer disease 16,17 Pick disease 12,17 Progressive supranuclear palsy 17 Dementia with Lewy bodies (Gross et al, personal communication, 2013)…”

Screening for Cognitive Dysfunction in Corticobasal Syndrome: Utility of Addenbrooke’s Cognitive Examination

“…Although initially described as a predominantly motor syndrome, an increasing number of cases in whom cognitive involvement predominates have been reported [1,2,3,4,5,6,7]. As a result, CBS is now regarded as a complex disorder which affects motor and cognitive function although the relative importance of these two major features remains controversial.…”