The purpose of this investigation was to determine the test-retest response consistency rate on a semantic memory task in persons with dementia of the Alzheimer type (DAT). Ten mildly and 13 moderately impaired DAT subjects and 14 normal controls matched for age, years of education, and estimated IQ participated in this study. The Peabody Picture Vocabulary Test (PPVT) was administered twice to each subject with a seven day inter-test interval. The mild and moderate DAT subjects responded inconsistently to significantly more PPVT items than normal controls. When the effects of guessing were considered, moderate DAT subjects gave significantly more inconsistent PPVT responses than normal controls and mild DAT subjects showed a trend towards giving more inconsistent responses. These results substantiate the conclusion that the impairment of specific conceptual knowledge in DAT subjects cannot be reliably measured with a single administration of a semantic memory task such as the PPVT.

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Emerging evidence supports the use of methylphenidate (MPH) for the treatment of apathy in Alzheimer’s disease (AD). This study aimed to investigate the additional effects of MPH on attention in an AD sample and the relationship between apathy and attention. AD patients enrolled in a randomized, double-blind placebo-controlled study to examine the safety and efficacy of MPH (10mg PO twice daily) for the treatment of apathetic symptoms were tested on attention and apathy every 2 weeks for 6 weeks. A mixed effects linear regression revealed attention change scores (endpoint - baseline) over time favouring MPH (δ=1.01, p=0.03), though there were no significant associations between apathy and attention change scores (r=-0.08, p=0.54). These results suggest that while MPH can improve both apathy and attention, the effects appear independent in this patient population. This study provides insight into the different effects MPH can produce in a heterogeneous disease such as AD.

Emerging evidence supports the use of methylphenidate (MPH) for the treatment of apathy in Alzheimer’s disease (AD). This study aimed to investigate the additional effects of MPH on attention in an AD sample and the relationship between apathy and attention. AD patients enrolled in a randomized, double-blind placebo-controlled study to examine the safety and efficacy of MPH (10mg PO twice daily) for the treatment of apathetic symptoms were tested on attention and apathy every 2 weeks for 6 weeks. A mixed effects linear regression revealed attention change scores (endpoint - baseline) over time favouring MPH (δ=1.01, p=0.03), though there were no significant associations between apathy and attention change scores (r=-0.08, p=0.54). These results suggest that while MPH can improve both apathy and attention, the effects appear independent in this patient population. This study provides insight into the different effects MPH can produce in a heterogeneous disease such as AD.

The presence of white matter hyperintensities (WMH) and silent infarcts on magnetic resonance imaging is a common finding in elderly individuals. This subcortical ischemic vasculopathy is associated with age and cerebrovascular risk factors and can increase the risk of dementia, yet the contribution of subcortical vascular disease to the clinical profile and progression of Alzheimer’s disease patients is still relatively poorly understood. This study assessed the presence, severity and progression of WMH and lacunar infarcts and studied their relationship with measures of brain function and cognition in 64 patients with Alzheimer’s disease. Both a visual rating scale and volumetric tissue segmentation analysis were used to evaluate brain-behaviour relationships of WMH seen on T2-weighted and Proton Density MRI scans. In addition to describing the topographical distribution of WMH and lacunes, and examining sex differences, the volume and location of WMH were correlated with executive function, frontal lobe perfusion, and medial temporal lobe atrophy. The results confirm and extend previous findings suggesting that WMH are located primarily in the frontal and parietal regions and are associated with mild decline in tasks of executive function. WMH severity was not associated with a decrease in frontal lobe perfusion as measured by Single Photon Emission Computed Tomography. The investigation of different WMH subtypes revealed that lacunar infarcts were found most often within deep WMH. At one year follow-up, progression was seen in deep WMH, specifically in the frontal lobe and in lacunes found within the periventricular regions. Furthermore, progression in WMH was associated with a decline in cognition. Taken together, these studies indicate the utility of measuring WMH by subtype (periventricular and deep WMH and lacunes) in understanding progression patterns and brain-behavior relationships. Since, subcortical ischemic vasculopathy may be potentially preventable; this study underlines the need to study interventions that address risk factors for the development of small vessel cerebrovascular disease, which may be helpful in preventing disability in the elderly.