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Joel Eppig,
Denene Wambach,
Christine Nieves,
Catherine C Price,
Melissa Lamar,
Lisa Delano-Wood,
Tania Giovannetti,
Brianne M Bettcher,
Dana L Penney, Rod Swenson,
Carol Lippa,
Anahid Kabasakalian,
Mark W Bondi,
David J Libon
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ABSTRACT: Libon et al. (2010) provided evidence for three statistically determined clusters of patients with mild cognitive impairment (MCI): amnesic (aMCI), dysexecutive (dMCI), and mixed (mxMCI). The current study further examined dysexecutive impairment in MCI using the framework of Fuster's (1997) derailed temporal gradients, that is, declining performance on executive tests over time or test epoch. Temporal gradients were operationally defined by calculating the slope of aggregate letter fluency output across 15-s epochs and accuracy indices for initial, middle, and latter triads from the Wechsler Memory Scale-Mental Control subtest (Boston Revision). For letter fluency, slope was steeper for dMCI compared to aMCI and NC groups. Between-group Mental Control analyses for triad 1 revealed worse dMCI performance than NC participants. On triad 2, dMCI scored lower than aMCI and NCs; on triad 3, mxMCI performed worse versus NCs. Within-group Mental Control analyses yielded equal performance across all triads for aMCI and NC participants. mxMCI scored lower on triad 1 compared to triads 2 and 3. dMCI participants also performed worse on triad 1 compared to triads 2 and 3, but scored higher on triad 3 versus triad 2. These data suggest impaired temporal gradients may provide a useful heuristic for understanding dysexecutive impairment in MCI.
Journal of the International Neuropsychological Society 01/2012; 18(1):20-8. · 2.76 Impact Factor
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David J Libon,
Mark W Bondi,
Catherine C Price,
Melissa Lamar,
Joel Eppig,
Denene M Wambach,
Christine Nieves,
Lisa Delano-Wood,
Tania Giovannetti,
Carol Lippa,
Anahid Kabasakalian,
Stephanie Cosentino, Rod Swenson,
Dana L Penney
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ABSTRACT: Using cluster analysis Libon et al. (2010) found three verbal serial list-learning profiles involving delay memory test performance in patients with mild cognitive impairment (MCI). Amnesic MCI (aMCI) patients presented with low scores on delay free recall and recognition tests; mixed MCI (mxMCI) patients scored higher on recognition compared to delay free recall tests; and dysexecutive MCI (dMCI) patients generated relatively intact scores on both delay test conditions. The aim of the current research was to further characterize memory impairment in MCI by examining forgetting/savings, interference from a competing word list, intrusion errors/perseverations, intrusion word frequency, and recognition foils in these three statistically determined MCI groups compared to normal control (NC) participants. The aMCI patients exhibited little savings, generated more highly prototypic intrusion errors, and displayed indiscriminate responding to delayed recognition foils. The mxMCI patients exhibited higher saving scores, fewer and less prototypic intrusion errors, and selectively endorsed recognition foils from the interference list. dMCI patients also selectively endorsed recognition foils from the interference list but performed similarly compared to NC participants. These data suggest the existence of distinct memory impairments in MCI and caution against the routine use of a single memory test score to operationally define MCI.
Journal of the International Neuropsychological Society 09/2011; 17(5):905-14. · 2.76 Impact Factor
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ABSTRACT: The introduction of diagnostic criteria for vascular dementia has helped to re-define the impact of various subcortical neuropathologies on aging; however, state-of-the-art neuroimaging techniques and autopsy studies suggest that not all structural brain alterations associated with vascular dementia are exclusive to this neurodegenerative process alone. Thus, a detailed analysis of the cognitive phenotype associated with ischaemic vascular disease is key to our understanding of subcortical neuropathology and its associated behaviors. Over the past twenty years, we have operationally defined this cognitive phenotype using the Boston Process Approach to neuropsychological assessment. This has led to both an empirical, as well as a theoretical understanding of three core constructs related to the dysexecutive syndrome associated with ischaemic vascular disease affecting periventricular and deep white matter as well as subcortical structures connecting these regions with the prefrontal cortex. Thus, difficulties with mental set, cognitive control and mental manipulation negatively impact executive functioning. This review will outline the subtle markers underlying this prefrontal dysfunction, i.e., the dysexecutive phenotype, associated with ischaemic vascular disease and relate it to fundamental impairments of gating subserved by basal ganglia-thalamic pathways within and across various dementia syndromes.
Behavioural neurology 01/2010; 22(1-2):53-62. · 1.77 Impact Factor
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David J Libon,
Sharon X Xie,
Joel Eppig,
Graham Wicas,
Melissa Lamar,
Carol Lippa,
Brianne M Bettcher,
Catherine C Price,
Tania Giovannetti, Rod Swenson,
Denene M Wambach
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ABSTRACT: A group of 94 nondemented patients self-referred to an outpatient memory clinic for memory difficulties were studied to determine the incidence of single versus multi-domain mild cognitive impairment (MCI) using Petersen criteria. Fifty-five community dwelling normal controls (NC) participants without memory complaints also were recruited. Tests assessing executive control, naming/lexical retrieval, and declarative memory were administered. Thirty-four patients exhibited single-domain MCI, 43 patients presented with multi-domain MCI. When the entire MCI sample (n = 77) was subjected to a cluster analysis, 14 patients were classified with amnesic MCI, 21 patients with dysexecutive MCI, and 42 patients were classified into a mixed/multi-domain MCI group involving low scores on tests of letter fluency, "animal" fluency, and delayed recognition discriminability. Analyses comparing the three cluster-derived MCI groups versus a NC group confirmed the presence of memory and dysexecutive impairment for the amnesic and dysexecutive MCI groups. The mixed MCI group produced lower scores on tests of letter fluency compared with the amnesic MCI and NC groups and lower scores on tests of naming and memory compared with the NC group. In summary, multi-domain MCI is quite common. These data suggest that MCI is a highly nuanced and complex clinical entity.
Journal of the International Neuropsychological Society 11/2009; 16(1):84-93. · 2.76 Impact Factor
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ABSTRACT: Our orientation regarding the dementias has changed during the past 30 yr. For example, in the not too distant past, illnesses
such as Alzheimer’s disease (AD) and Pick’s disease were believed to be rare, if not obscure, illnesses (1). This viewpoint is juxtaposed to contemporaneous ideas put forth by Katzman and colleagues (2) who believed that AD was not only prevalent but represented a major public health problem. During the past 10 yr, the diagnosis
of dementia has become increasingly complex, requiring the consideration of an array of conditions, including AD, vascular
dementia (VaD), dementia with Lewy body (DLB), frontal-temporal dementia (FTD), cortical basilar degeneration (CBD), and subcortical
dementias, such as progressive supernuclear palsy (PSP) and Parkinson’s disease.
12/2004: pages 281-293;
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ABSTRACT: Differential patterns of executive function deficits (EFD) exist in cortical and subcortical dementia; however, little work exists attempting to integrate these findings into a conceptual framework. The current study aimed to characterize EFD in cortical and subcortical dementia. Patients with Alzheimer's disease (AD; n = 65), subcortical ischemic vascular dementia (IVD; n = 64), or Parkinson's disease with dementia (dPD; n = 21) completed a variety of measures purported to require executive systems. We extracted variables of interest from measures shown in a growing body of literature to be associated with EFD in dementia. These measures included the Boston Revision of the WMS Mental Control subtest, letter fluency, WAIS-R Similarities subtest, CVLT, the Graphical Sequence Test-Dementia version, and Clock Drawing. When submitted to a PCA with varimax rotation, these variables produced a four-component solution (62% of the variance). Component 1 appeared to reflect adequacy of working memory, Component 2 irrelevant or context nonspecific interference, Component 3 reflected response preparation and Component 4 relevant or context-specific interference. Post hoc analyses of z-transformed composite scores revealed that AD differentially affected context-specific interference, IVD and dPD disrupted working memory and response preparation while IVD differentially affected context non-specific interference. EFD in dementia can be divided into specific components that are differentially impaired by cortical and subcortical dementias. Implications for an overall conceptual framework of EFD in dementia are discussed.
The Clinical Neuropsychologist 03/2004; 18(1):22-31. · 2.12 Impact Factor
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ABSTRACT: Throughout the 1990s a variety of schemes for the diagnosis of Vascular Dementia (VaD) were proposed, including the ADDTC criteria for Ischemic Vascular Dementia, the NINDS-AIREN criteria for Vascular Dementia, Bennett's criteria for Binswanger's disease, and the ICD-10 criteria for Vascular Dementia. We undertook a retrospective analysis of a series of ambulatory outpatients with dementia to determine the prevalence with which patients were diagnosed by each of these diagnostic schemes, and to survey the clinical characteristics associated with VaD. We found that the diagnostic schemes for VaD were not interchangeable; patients diagnosed with VaD using one set of criteria were not necessarily diagnosed with VaD using other criteria. The most common clinical characteristics associated with VaD, regardless of the diagnostic scheme that was used, were hypertension, extensive periventricular and deep white matter alterations on MRI (leukoaraiosis), and differential impairment on neuropsychological tests that assess the ability to establish/maintain mental set and visuoconstruction, with relatively higher scores on tests of delayed recognition memory. Interestingly, the majority of VaD patients obtained low scores on the Modified Ischemic Scale, since cortical infarcts and a history of a sudden onset and/or step-wise decline in cognitive function were rare. We conclude that the current diagnostic schemes for VaD do not necessarily consider the heterogeneous nature of VaD. A new paradigm that seeks to describe, in addition to diagnosing dementia associated with cerebrovascular disease is discussed.
The Clinical Neuropsychologist 03/2004; 18(1):6-21. · 2.12 Impact Factor
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ABSTRACT: We investigated the different mechanisms that may underlie deficits in verbal concept formation among patients with Alzheimer's disease (AD) and ischaemic vascular dementia (IVD) associated with periventricular and deep white matter alterations. Concept formation was assessed with the WAIS-R Similarities subtest (SIM). Two types of errors were re-coded from the 0-point responses as scored by the WAIS-R manual. In set errors (e.g., dog–lion “they're alive”) were coded when patients reported a very vague superordinate concept for the word pair. Out of set responses (e.g., dog–lion “the lion roars and the dog barks”) were coded when a response was clearly out of mental set, i.e., when participants were unable to provide a superordinate concept for the word pair. Between-group comparisons demonstrated no difference in SIM test performance according to the scoring system described in the WAIS-R manual. Nonetheless, AD patients produced a greater proportion of in set errors, while IVD patients produced a greater proportion of out of set errors. Out of set errors were highly associated with measures of executive function, while in set errors were associated with measures related to delayed recognition memory and semantic intrusion errors. We conclude that the underlying deficits that contribute to poor concept formation differ between AD and IVD patients. In IVD impaired concept formation is related to deficits in the executive systems necessary to monitor responses and sustain mental set. In AD, by contrast, the deficit appears to be secondary to impaired verbal response selection.
Archives of Clinical Neuropsychology 09/2001; · 2.18 Impact Factor
