Executive Abilities as Reflected by Clock Hand Placement: Frontotemporal Dementia Versus Early-Onset Alzheimer Disease.

The clock-drawing test (CDT) is widely used in clinical practice to diagnose and distinguish patients with dementia. It remains unclear, however, whether the CDT can distinguish among the early-onset dementias. Accordingly, we examined the ability of both quantitative and qualitative CDT analyses to distinguish behavioral variant frontotemporal dementia (bvFTD) and early-onset Alzheimer disease (eAD), the 2 most common neurodegenerative dementias with onset <65 years of age. We hypothesized that executive aspects of the CDT would discriminate between these 2 disorders. The study compared 15 patients with bvFTD and 16 patients with eAD on the CDT using 2 different scales and correlated the findings with neuropsychological testing and magnetic resonance imaging. The total CDT scores did not discriminate bvFTD and eAD; however, specific analysis of executive hand placement items successfully distinguished the groups, with eAD exhibiting greater errors than bvFTD. The performance on those executive hand placement items correlated with measures of naming as well as visuospatial and executive function. On tensor-based morphometry of the magnetic resonance images, executive hand placement correlated with right frontal volume. These findings suggest that lower performance on executive hand placement items occurs with involvement of the right dorsolateral frontal-parietal network for executive control in eAD, a network disproportionately affected in AD of early onset. Rather than the total performance on the clock task, the analysis of specific errors, such as executive hand placement, may be useful for early differentiation of eAD, bvFTD, and other conditions.

Clinical amyloid imaging in logopenic progressive aphasia.

The introduction of florbetapir (Amyvid) positron emission tomography biomarkers could dramatically change how we clinically evaluate young patients who present with nonamnestic cognitive complaints for possible Alzheimer disease (AD). Logopenic progressive aphasia (LPA) may be the most common example of this type of clinical problem. In most, but not all, cases, LPA is an early-onset AD variant presenting with language changes that can be difficult to distinguish from other progressive aphasias. We clinically evaluated 3 patients with LPA, in comparison with age-matched and severity-matched patients with typical amnestic AD, using florbetapir amyloid neuroimaging. The fluorodeoxyglucose-positron emission tomography scans of LPA patients revealed focal hypometabolism in the left temporoparietal areas, and the florbetapir scans were diffusely positive for the presence of amyloid deposition. The florbetapir scans did not differ in distribution between patients with LPA and those with typical amnestic AD. Clinical amyloid imaging, although lacking localizing value, is a major advance in the assessment of early-onset and nonamnestic patients for the presence of ß-amyloid Alzheimer pathology.

Suicidal behavior in dementia: a special risk in semantic dementia.

BACKGROUND: Some studies report a low suicide risk in general dementia and in Alzheimer's disease (AD). OBJECTIVE: To evaluate suicidal behavior among patients with semantic dementia (SD), a disorder that impairs semantic knowledge. METHODS: We reviewed the presence of active suicidal behavior and related factors among 25 patients with SD compared to 111 age-matched patients with early-onset AD. RESULTS: In all, 5 (20%) patients with SD had suicidal behavior (2 successfully killed themselves) compared to 1 (0.9%) with AD (P < .001). There was significantly more depression and greater premorbid history of suicidal behavior among the patients with SD compared to those with AD. Among the patients with SD, those with suicidal behavior, compared to those without, had more depression and greater insight into their deficits. CONCLUSIONS: Patients with SD are at special risk of committing suicide, particularly if they have depression and preserved insight. Possible mechanisms include an impaired sense of semantic competence with increased impulsivity.