This abstract was published today on PubMed. CBD is considered a subtype of FTLD (frontotemporal lobar degeneration). This Drexel University study assessed whether the patterns of neuropsychological impairment in CBD, three other FTLD subtypes, and AD remain distinct over the duration of the disease or “devolve into a common, undifferentiated neuropsychological state.” The researchers found that the patterns remained distinct. For CBD, patients “presented with performance on visuoconstructional tests.” A quick Google search revealed several visuoconstructional tests including Constructional Praxis, Stick Design, and Bicycle Drawing. Perhaps the clock test is also a visuoconstructional test.
Robin
Neuropsychology. 2009 May;23(3):337-46.
Neuropsychological decline in frontotemporal lobar degeneration: A longitudinal analysis.
Libon DJ, Xie SX, Wang X, Massimo L, Moore P, Vesely L, Khan A, Chatterjee A, Coslett HB, Hurtig HI, Liang TW, Grossman M.
Department of Neurology, Drexel University College of Medicine.
Few studies have assessed whether the patterns of neuropsychological impairment in patients with different frontotemporal lobar degeneration (FTLD) subtypes remain distinct over the duration of their illness or devolve into a common, undifferentiated neuropsychological state.
A longitudinal neuropsychological analysis was obtained over 100 months assessing executive control, language/naming, and visuoconstruction in 441 patients diagnosed with Alzheimer’s disease (AD) and four FTLD subtypes, i.e., a social comportment/dysexecutive (SOC/EXEC) disorder; progressive non-fluent aphasia (PNFA); semantic dementia (SemD); and corticobasal degeneration (CBD).
Initial group differences on each measure were maintained over the duration of illness, including several double dissociations. For example, AD patients exhibited a decline in ‘animal’ fluency; PNFA patients had difficulty on tests of executive control, SemD maintained their impairment on tests of naming, and CBD had presented with performance on visuoconstructional tests.
None of the group by neuropsychological task interactions evaluating longitudinal decline was significant, suggesting that performance does not converge onto a common subtype over time. These data indicate that distinct patterns of neuropsychological impairment are maintained longitudinally, reflecting the unique anatomic distribution of relative disease burden in AD and FTLD.
PubMed ID#: 19413447 (see pubmed.gov for abstract only)