David J. Libon

Further analyses of clock drawings among demented and nondemented older subjects

In a previous article we described a 10-point scoring system (i.e., scale 1) to grade clock drawings to command and copy with hands set for ten after 11 among demented patients. Alzheimers subjects (AD) improved from the command to copy conditions, whereas subjects with ischaemic vascular dementia (IVD) did not. To investigate the underlying cognitive deficits responsible for this profile, an additional scale was developed (scale 2) that tallied errors in graphomotor functioning, hand/number placement, and executive control. On an independent sample of subjects, AD subjects, again, made significant improvement on scale 1 from the command to copy condition, whereas no such improvement occurred among the IVD subjects. On scale 2, IVD subjects made more graphomotor errors in the command condition, and more executive control and more total errors in the copy conditions than AD subjects. A number of positive correlations were noted between tests of language and memory on scale 1. By contrast, scores on tests of executive control declined as scale 2 errors increased. In addition, a principal component analysis indicated that scale 2 test performance loaded on a factor with other tests related to executive control. These results suggest that impairment in frontal systems functioning may explain why IVD subjects do not improve from the command to copy conditions on scale 1. Such a pattern of performance in clock drawing may also be helpful in making a differential diagnosis between AD and IVD.

Patterns of neuropsychological impairment in frontotemporal dementia

Objective: To differentiate frontotemporal dementia (FTD) subtypes from each other and from probable Alzheimer disease (AD) using neuropsychological tests. Methods: Patients with FTD and AD (n = 109) were studied with a comprehensive neuropsychological protocol at first contact. Data were subjected to a principal components analysis (PCA) to extract core neuropsychological features. A five-factor solution accounted for 72.89% of the variance and yielded factors related to declarative memory, working memory/visuoconstruction, processing speed/mental flexibility, lexical retrieval, and semantic memory. Results: Between- and within-group analyses revealed that patients with AD obtain their lowest scores on tests of declarative memory while semantic dementia (SemD) patients are particularly disadvantaged on tests of semantic memory. On tests of processing speed/mental flexibility time to completion was faster for social comportment/dysexecutive (SOC/EXEC) patients, but these patients made more errors on some tests. Patients with corticobasal degeneration (CBD) and progressive nonfluent aphasia (PNFA) were impaired on tests of working memory. Logistic regression analyses using factor scores successfully assigned FTD subgroups and AD patients into their respective diagnostic categories. Conclusion: Patients with differing frontotemporal dementia phenotypes can be distinguished from each other and from Alzheimer disease using neuropsychological tests.

A Nine—Word dementia version of the california verbal learning test

Abstract The validity of an experimental 9-word version of the California Verbal Learning Test (CVLT) was investigated. The construct validity of the 9-word CVLT was assessed with a principal component analysis (PCA) on a sample of nondemented subjects. A three—factor solution, related to immediate free recall, delayed recall and recognition, and intrusion errors was produced. Construct validity was also assessed by comparing subjects with probable Alzheimers disease (AD), probable ischemic vascular dementia (IVD), and a normal control (NC) group. AD subjects evidenced little learning on immediate free recall test conditions, made no improvement on cued recall or recognition test conditions, and produced copious amounts of intrusion errors. IVD subjects performed similarly to AD subjects on immediate free recall test conditions, but improved on all cued recall and recognition test conditions, and made significantly fewer intrusion errors. The NC group was vastly superior to both groups of demented subjec...

Impairment in category fluency in ischemic vascular dementia.

The underlying mechanisms for impaired output on letter (F, A, and S) and category (e.g., animal) word list generation (WLG) tasks in subcortical ischemic vascular dementia (IVD) were investigated. Normal control (NC) and Alzheimers disease (AD) participants were also studied. IVD and NC participants performed better on category than letter WLG tasks, whereas the opposite was observed among AD participants. IVD participants produced fewer responses than AD participants on letter WLG tasks, but there was no difference between AD and IVD participants on the animal WLG task. AD participants scored lower than IVD and NC participants on animal WLG indexes measuring semantic knowledge. There were few differences between IVD and NC participants. The reduced output on the animal WLG task for IVD participants is consistent with search-retrieval deficits. The reduced output of AD participants may be caused by degraded semantic knowledge.

Visuoconstructional problems in dementia: Contribution of executive systems functions

Visuoconstructional ability was assessed by asking patients diagnosed with Alzheimers disease (AD), ischaemic vascular dementia (IVD), and Parkinsons disease (PD) and a normal control group (NC) to copy a modification of the Rey-Osterrieth Complex Figure (M-ROCF). The drawings of the NC group were superior to all dementia participants. AD patients generally outperformed IVD and PD patients; however, there were few differences between IVD and PD groups. Nonetheless, the drawings of IVD and PD patients were very fragmented and contained numerous perseverations and omissions. Despite these errors, patients with IVD and PD obtained higher delayed recognition memory scores than AD patients. Correlational analyses among dementia patients between neuropsychological tests and the copy of the M-ROCF found that accurate figure copy was most consistently correlated with tests of working memory, that is, tests requiring patients to monitor their behavior and sustain a complex mental set while performing mental manipulations. By contrast, no relationship between executive function tests related to measures of response selection/inhibition or other domains of neuropsychological functioning was found.

Progressive Peripheral Agraphia

We describe RW, a patient who presented with writing difficulty that deteriorated over time. While her graphemes were typically legible, her writing was extremely slow, and her letters were written in an inconsistent and heterogeneous manner (e.g. each ‘a’ in the word ‘banana’ was produced in a different way). Her mental imagery of letters was impoverished, and she also produced allographic errors in her writing. She had some spelling errors as well, but many of these were due to omissions, perseverations, and motor operations. A positron emission tomography scan demonstrated superior parietal occipital and superior frontal defects that were more evident on the left than the right. Our observations are consistent with the hypothesis that RW has a deficit retrieving physical letter forms as manifested by her heterogeneous and slow production of letter forms. This disruption of grapheme retrieval is associated with interruption of a superior frontal-parietal system in the left hemisphere.

Periventricular white matter alterations, dementia, and binswanger's disease

Although periventricular white matter alterations (PWMA) are commonly reported on magnetic resonance imaging (MRI) scans of elderly individuals, a consistent pattern of neuropsychological deficits has yet to be found. However, there are some findings suggesting that executive functions (Luria, 1980) are more impaired than other areas of neuropsychological functioning. We undertook a prospective study of two groups of elderly, demented patients with and without PWMA as measured by MRI. The results demonstrated that subjects with greater white matter alterations performed worse on some executive function tests (e.g., Trail Making Test‐Part B and competing programs/go‐no‐go), whereas there were no differences in other areas of neuropsychological functioning. There were no between‐group differences on the Modified Ischemic Scale (Rosen, Terry, Fuld, Katzman, & Peck, 1980) or on measures of depression. Other pertinent clinical and methodological issues related to the clinical presentation of PWMA, as well as B...