The neuropsychological pattern of corticobasal degeneration

Abstract

The pattern of cortical and subcortical neuropathologic lesions in corticobasal degeneration (CBD) should predict a specific cognitive profile in this disease. To characterize this profile and to determine its specificity by comparison with progressive supranuclear palsy (PSP) and senile dementia of the Alzheimer's type (SDAT), we used an extensive neuropsychological battery assessing global efficiency, executive functions, various tests of encoding and retrieval, dynamic motor organization, and upper limb praxis. We compared the performance of patients with CBD (n = 15) with that of controls (n = 19) matched for age and education, and with that of patients with PSP and SDAT (15 in each group), matched for severity of dementia and depression. Patients with CBD showed: (1) a moderate global deterioration; (2) a dysexecutive syndrome similar to that of patients with PSP and more severe than in SDAT; (3) explicit learning deficits, without retention difficulties and easily compensated by using the same semantic cues at encoding and retrieval as in PSP; this was in contrast with SDAT where cued recall and recognition were also impaired; (4) disorders of dynamic motor execution (temporal organization, bimanual coordination, control, and inhibition) similar to those of patients with PSP and not in SDAT; (5) asymmetric praxis disorders (posture imitation, symbolic gesture execution, and object utilization) that were not observed in PSP or SDAT. Patients with CBD show a specific neuropsychological pattern associating a dysexecutive syndrome, likely due to degeneration of the basal ganglia and prefrontal cortex, and asymmetric praxis disorders, which might be related to premotor and parietal lobe lesions. This neuropsychological profile may help to distinguish this condition clinically from other neurodegenerative diseases.

Differentiating cognitive impairment due to corticobasal degeneration and Alzheimer disease

“…The prevalence of this symptom was surprising given the relatively minor impairments on tests of episodic memory and relative paucity of tauopathy in the mesial temporal lobes, a finding observed in other studies. 4,32,33 The distribution of tau pathology was similar to that reported previously in patients with CBS, 2,4,8,13,[34][35][36] suggesting that the predominance of early memory complaints may reflect deficits in strategies for encoding and retrieval, owing to disruption of structures more frequently affected by CBD, including frontotemporal subcortical areas. 15 Previous case series reported a low frequency of detection of classic CBS signs (i.e., asymmetric motor/sensory features, parkinsonism, and/or dystonia) at onset in patients with cognitive presentations of CBD.…”

Features of Regional Cerebral Glucose Metabolism Abnormality in Corticobasal Degeneration

“…On the other hand, the AD patients were more impaired in orientation and word recognition than the CBD patients. These features of cognitive impairment are compatible with previously reported findings [8]. In agreement with previous studies [10,[12][13][14], the CBD patients showed greater glucose metabolic asymmetries in the lateral frontal, lateral temporal, central and lateral parieto-occipital regions, in comparison with the normal controls.…”

“…We excluded the patients with complications of other neurological disease or evidence of focal brain lesions on MRI. Although the Lang exclusion criteria include cognitive disturbances other than apraxias, language disorders or dementia while the patient remains ambulatory, we did not apply them because CBD patients often manifest cognitive disturbances [2][3][4][5][6][7][8] and because cognitive and cortical impairment was the main focus in the present study. All CBD patients in this study had a markedly asymmetrical onset.…”

The cognitive side of essential tremor: what are the therapeutic implications?

“…In addition, many reports of neuropsychological performance in patients with ET have highlighted a pattern of attentional and executive dysfunction that is analogous to that observed in neurodegenerative diseases affecting subcortical white matter [Schmidtke and Hull, 2002;Traykov et al 2002;Tierney et al 2001;Doddy et al 1998;Lafosse et al 1997] and basal ganglia structures [Troster et al 2002;Lundervold et al 1994;Pillon et al 1995;Cummings, 1998]. …”