Neuropsychological differences between frontotemporal lobar degeneration and Alzheimer's disease

Memory impairment is the main clinical feature in Alzheimer disease (AD), whereas in frontotemporal lobar degeneration (FTLD) behavioral and language disorders predominate.

To investigate possible differences between the neuropsychological performance in FTLD and AD.

Fifty-six AD patients (mean age=72.98±7.43; mean schooling=9.62±4.68; 35 women and 21 men), 17 FTLD patients (mean age=67.64±7.93; mean schooling=12.12±4.77; 9 women and 8 men), and 60 controls (mean age=68.90±7.48; mean schooling=10.72±4.74; 42 women and 18 men) were submitted to a Dementia Rating Scale (DRS) and a comprehensive neuropsychological evaluation composed of tasks assessing attention, visuoperceptual abilities, constructive abilities, executive functions, memory and language.

DRS total score and subscales were not able to differentiate FTLD from AD patients. However, FTLD and AD patients showed statistically significant differences in performance in tests of verbal (Logical Memory, Rey Auditory Verbal Learning Test) and visual (Visual Reproduction, recall of the Rey Complex Figure) episodic memory, verbal immediate memory (Logical Memory), attention with interference (Trail Making Test - Part B), verbal fluency (semantic and phonemic) and concept formation (WCST).

Contrary to expectations, only a few tasks executive function tasks (Trail Making Test - Part B, F.A.S. and WCST) and two memory tests (verbal and visual episodic memory tests) were able to differentiate between FTLD and AD patients.