[Differential cognitive profiles of fronto-temporal dementia and Alzheimer's disease]

When the clinical picture consists of prominent cognitive impairments (e.g. amnesia) with relatively mild behavioral symptoms, it can be very difficult to distinguish frontal lobe dementia (FLD) from Alzheimer disease (AD). However, these conditions may have distinct cognitive profiles that could be detected by means of neuropsychological testing. The objective was to examine the early differential cognitive feature between FLD and AD.

Twelve patients with FLD, 20 patients with AD, and 20 normal subjects matched for age and educational level were evaluated with the Folstein Mini Mental State Examination, the Signoret Memory Battery, the Boston Naming Test, Verbal Fluency (FAS), the Wechsler Adult Intelligence Scale, and the Trail Making Test. The FLD patients met the Lund and Manchester criteria, and the AD patients met the National Institute of Neurological Disorders and Stroke-Alzheimer Disease and Related Disorders Association (NINDS-ADRDA) criteria for clinically probable AD.

FLD and AD patients were matched for the severity of dementia using the Global Deterioration Scale (3.8 +/- 0.3 versus 3.9 +/- 0.5 respectively). Mean Z scores were calculated in order to facilitate the comparison between the neuropsychological profiles obtained. FLD patients scored significantly better than AD patients in memory test, calculation, visuospatial abilities, and the naming test. AD patients performed better on executive tasks.

These findings suggest that neuropsychological examination may be useful in differential diagnosis between FLD and AD