Music is a complex acoustic signal that relies on a number of different brain and cognitive processes to create the sensation of hearing. Changes in hearing function are generally not a major focus of concern for persons with a majority of neurodegenerative diseases associated with dementia, such as Alzheimer disease (AD). However, changes in the processing of sounds may be an early, and possibly preclinical, feature of AD and other neurodegenerative diseases. The aim of this chapter is to review the current state of knowledge concerning hearing and music perception in persons who have a dementia as a result of a neurodegenerative disease. The review focuses on both peripheral and central auditory processing in common neurodegenerative diseases, with a particular focus on the processing of music and other non-verbal sounds. The chapter also reviews music interventions used for persons with neurodegenerative diseases.
neurodegenerative disease; Alzheimer’s disease; frontotemporal dementia; Parkinson’s disease; corticobasal degeneration; progressive supranuclear palsy; melody; rhythm; environmental sounds; auditory evoked potentials
Enhancing quality of life (QOL) of older adults is an international area of focus. Identifying factors and experiences that contribute to QOL of older adults helps promote optimal levels of functioning. This study examines the relationship between perceived benefits associated with choral singing and quality of life (QOL) among community-dwelling older adults.
One hundred and seventeen older adults who sing in community choirs in Jyväskylä, Finland completed self-report measures of QOL (WHOQOL-Bref), depressive symptoms, and a questionnaire about the benefits of singing in choir. Correlational analyses and linear regression models were used to examine the association between the benefits of singing in choir and QOL.
Both correlation and regression analyses found significant relationships between the benefits of choral singing and three QOL domains: psychological, social relationships, and environment but not physical. These associations remained significant after adjusting for age and depressive symptoms. As hypothesized, older choral singers who reported greater benefits of choir singing had higher QOL in multiple domains. The older choral singers in the study also reported few symptoms of depression and high overall QOL and satisfaction with health.
Results suggest that singing in a community choir as an older adult may positively influence several aspects of QOL. These results suggest that community choral singing may one potential avenue for promoting quality of life in older adults.
Music; choir; quality of life; aging
To compare music recognition in patients with frontotemporal dementia, semantic dementia, Alzheimer disease, and controls and to evaluate the relationship between music recognition and brain volume.
Recognition of familiar music depends on several levels of processing. There are few studies about how patients with dementia recognize familiar music.
Subjects were administered tasks that assess pitch and melody discrimination, detection of pitch errors in familiar melodies, and naming of familiar melodies.
There were no group differences on pitch and melody discrimination tasks. However, patients with semantic dementia had considerable difficulty naming familiar melodies and also scored the lowest when asked to identify pitch errors in the same melodies. Naming familiar melodies, but not other music tasks, was strongly related to measures of semantic memory. Voxel-based morphometry analysis of brain MRI showed that difficulty in naming songs was associated with the bilateral temporal lobes and inferior frontal gyrus, whereas difficulty in identifying pitch errors in familiar melodies correlated with primarily the right temporal lobe.
The results support a view that the anterior temporal lobes play a role in familiar melody recognition, and that musical functions are affected differentially across forms of dementia.
Pitch; Melody; temporal lobe; auditory perception
There are few studies that evaluate the clinical outcomes of individuals with non-amnestic mild cognitive impairment (MCI). The purpose of this study was to evaluate baseline predictors of clinical progression after 2 years for patients with dysexecutive MCI (dMCI), a single-domain non-amnestic MCI subgroup.
We evaluated clinical progression in a sample of 31 older adults with dMCI. Clinical progression was defined as a worsening on the Clinical Dementia Rating sum of boxes at the 2-year visit, whereas patients were classified as stable if the score did not worsen over 2 years. We compared baseline brain MRI, neuropsychological tests, and health risk factors.
Twelve individuals with dMCI progressed clinically, and 19 individuals remained stable over 2 years. Compared to the stable dMCI patients, the dMCI patients who progressed showed brain atrophy in the bilateral insula and left lateral temporal lobe on MRI. dMCI patients who progressed were also older, had lower baseline performance on category fluency and a spatial location task, and reported fewer dysexecutive symptoms. Health risk factors, except hypertension, did not differ between groups.
The results suggest that dMCI patients who progress relatively quickly over 2 years may have unique clinical and brain MRI features.
Executive function; Non-amnestic mild cognitive impairment; Dysexecutive mild cognitive impairment
Modern cognitive neuroscientific theories and empirical evidence suggest that brain structures involved in movement may be related to action-related semantic knowledge. To test this hypothesis, we examined the naming of environmental sounds in patients with corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP), two neurodegenerative diseases associated with cognitive and motor deficits. Subjects were presented with 56 environmental sounds: 28 of objects that required manipulation when producing the sound, and 28 that required no manipulation. Subjects were asked to provide the name of the object that produced the sound and also complete a sound-picture matching condition. Subjects included 33 individuals from four groups: CBD/PSP, Alzheimer disease, frontotemporal dementia, and normal controls. We hypothesized that CBD/PSP patients would exhibit impaired naming performance compared with controls, but the impairment would be most apparent when naming sounds associated with actions. We also explored neural correlates of naming environmental sounds using voxel-based morphometry (VBM) of brain MRI. As expected, CBD/PSP patients scored lower on environmental sounds naming (p<0.007) compared with the controls. In particular, the CBD/PSP patients scored the lowest when naming sounds of manipulable objects (p<0.05), but did not show deficits in naming sounds of non-manipulable objects. VBM analysis across all groups showed that performance in naming sounds of manipulable objects correlated with atrophy in the left premotor region, extending from area 6 to the middle and superior frontal gyrus. These results indicate an association between impairment in the retrieval of action-related names and the motor system, and suggest that difficulty in naming manipulable sounds may be related to atrophy in the premotor cortex. Our results support the hypothesis that retrieval of action-related semantic knowledge involves motor regions in the brain.
Subgroups of mild cognitive impairment (MCI) have been proposed, but few studies have investigated the non-amnestic, single-domain subgroup of MCI. The goal of the study was to compare clinical and neuroimaging characteristics of two single domain MCI subgroups: amnestic MCI (aMCI) and dysexecutive MCI (dMCI).
We compared the cognitive, functional, behavioral and brain imaging characteristics of patients with aMCI (n=26), dMCI (n=32) and age- and education-matched controls (n=36) using analysis of variance and chi-squared tests. We used voxel-based morphometry (VBM) to examine group differences in brain MRI atrophy patterns.
Patients with dMCI had significantly lower scores on the majority of executive function tests, increased behavioral symptoms, and left prefrontal cortex atrophy on MRI when compared to controls. In contrast, patients with aMCI had significantly lower scores on tests of memory and a pattern of atrophy including bilateral hippocampi and entorhinal cortex, right inferior parietal cortex, and posterior cingulate gyrus when compared to controls.
Overall, the clinical and neuroimaging findings provide support for two distinct single-domain subgroups of MCI, one involving executive function and the other involving memory. The brain imaging differences suggest that the two MCI subgroups have distinct patterns of brain atrophy.
Cognitive impairment in the absence of dementia is common in elderly individuals and is most often studied in the context of an isolated impairment in memory. In the current study, we report the neuropsychological and neuropathological features of a nondemented elderly individual with isolated impairment on a test of executive function (i.e., Trail Making Test) and preserved memory, language, and visuospatial function. Postmortem studies indicated that cortical neurofibrillary tangles (NFT) varied considerably, and some regions contained large numbers of neuritic senile plaques. Semiquantitative immunohistochemistry showed higher NFT and amyloid-beta (Aβ) loads in the frontal cortex relative to the temporal, entorhinal, occipital, and parietal cortices. A survey of the entire cingulated gyrus showed a wide dispersion of Aβ42 with the highest concentration in the perigenual part of the anterior cingulate cortex; Aβ appeared to be linked with neuron loss and did not overlap with the heaviest neuritic degeneration. The current case may represent a nonmemory presentation of mild cognitive impairment (executive mild cognitive impairment) that is associated with frontal and anterior cingulate pathology and may be an early stage of the frontal variant of Alzheimer disease.
Isolated executive impairment; Cortical neurofibrillary tangles; Amyloid peptides; Cingulate gyrus; Mild cognitive impairment
Functional impairment in community-dwelling older adults is common and is associated with poor outcomes. Our goal was to compare the contribution of impairment in executive function or global cognitive function to predicting functional decline and mortality.
We studied 7717 elderly women enrolled in a prospective study (mean age 73.3 years) and identified women with poor baseline executive function (score > 1 standard deviation [SD] below the mean on the Trail Making Test B (Trails B; n = 957, 12.4%), poor global cognitive function (score > 1 SD below the mean on a modified Mini-Mental State Examination [mMMSE], n = 387, 5.0%), impairment in both (n = 249, 3.2%), or no impairment (n = 6124, 79.4%). We compared level of functional difficulty (Activities of Daily Living [ADLs] and Instrumental ADLs [IADLs]) at baseline and at 6-year follow-up and survival at follow-up. We also determined if the association was independent of age, education, depression, medical comorbidities, and baseline functional ability.
At baseline, women with Trails B impairment only or impairment on both tests reported the highest proportion of ADL and IADL dependence compared to the other groups. At the 6-year follow-up after adjusting for age, education, medical comorbidities, depression, and baseline ADL or IADL, women with only Trails B impairment were 1.3 times more likely to develop an incident ADL dependence (adjusted odds ratio [OR] = 1.34; 95% confidence interval [CI], 1.07–1.69) and 1.5 times more likely to develop a worsening of ADL dependence (adjusted OR = 1.48; 95% CI, 1.16–1.89) when compared to women with no impairment on either test. In addition, women with only Trails B impairment had a 1.5-fold increased risk of mortality (adjusted hazard ratio [HR] = 1.48; 95% CI, 1.21–1.81). In contrast, women with impairment on only mMMSE were not at increased risk to develop incident ADL or IADL dependence, a worsening of ADL or IADL dependence, or mortality.
Compared to women with no impairment, women with executive function impairment had significantly worse ADL and IADL function cross-sectionally and over 6 years. Individuals with executive dysfunction also had increased risk of mortality. These results suggest that screening of executive function can help to identify women who are at risk for functional decline and decreased survival.
We examined the influence of a broad spectrum of life experiences on longitudinal cognitive trajectories in a demographically diverse sample of older adults.
Participants were 333 educationally, ethnically, and cognitively diverse older adults enrolled in a longitudinal aging study. Mixed-effects regression was used to measure baseline status in episodic memory, executive functioning, and semantic memory and change in a global cognition factor defined by change in these three domain-specific measures. We examined effects of life experience variables (literacy, childhood socioeconomic status, morphometric measures of physical development, life course physical and recreational activity) on longitudinal cognitive trajectories, covarying for age, APOE genotype and demographics (education, ethnicity, language).
Non-Latino whites had higher baseline cognition, but life experience variables attenuated ethnic differences in cognitive scores. Age, literacy, childhood socioeconomic status and physical activity significantly influenced baseline cognition. Age, APOE ε4 and decline in intellectually and socially stimulating recreational activity from mid to late life were independently associated with increased late life cognitive decline. Higher literacy and late life recreational activity were associated with less decline. Literacy had similar effects for English and Spanish readers/speakers. Bilingual English and Spanish speakers did not differ from English Speakers in cognitive performance.
Life experience variables, especially literacy level, were strongly related to baseline cognition and substantially attenuated effects of race/ethnicity and education. Cognitive change was best explained by age, APOE ε4, literacy, and current recreational activities. Literacy had robust associations with baseline cognition and cognitive change in both English and Spanish speakers.
Aging; cognitive change; individual differences; recreational activity; minority and diverse populations
Older adults are the fastest growing segment of the United States population. There is an immediate need to identify novel, cost-effective community-based approaches that promote health and well-being for older adults, particularly those from diverse racial/ethnic and socioeconomic backgrounds. Because choral singing is multi-modal (requires cognitive, physical, and psychosocial engagement), it has the potential to improve health outcomes across several dimensions to help older adults remain active and independent. The purpose of this study is to examine the effect of a community choir program (Community of Voices) on health and well-being and to examine its costs and cost-effectiveness in a large sample of diverse, community-dwelling older adults.
In this cluster randomized controlled trial, diverse adults age 60 and older were enrolled at Administration on Aging-supported senior centers and completed baseline assessments. The senior centers were randomly assigned to either start the choir immediately (intervention group) or wait 6 months to start (control). Community of Voices is a culturally tailored choir program delivered at the senior centers by professional music conductors that reflects three components of engagement (cognitive, physical, and psychosocial). We describe the nature of the study including the cluster randomized trial study design, sampling frame, sample size calculation, methods of recruitment and assessment, and primary and secondary outcomes.
The study involves conducting a randomized trial of an intervention as delivered in “real-world” settings. The choir program was designed using a novel translational approach that integrated evidence-based research on the benefits of singing for older adults, community best practices related to community choirs for older adults, and the perspective of the participating communities. The practicality and relatively low cost of the choir intervention means it can be incorporated into a variety of community settings and adapted to diverse cultures and languages. If successful, this program will be a practical and acceptable community-based approach for promoting health and well-being of older adults.
ClinicalTrials.gov NCT01869179 registered 9 January 2013.
Health promotion; Arts; Music; Health disparities; Older adults; Translational research; Community-based participatory research
To provide guidance on standards for reporting studies of diagnostic test accuracy for dementia disorders.
An international consensus process on reporting standards in dementia and cognitive impairment (STARDdem) was established, focusing on studies presenting data from which sensitivity and specificity were reported or could be derived. A working group led the initiative through 4 rounds of consensus work, using a modified Delphi process and culminating in a face-to-face consensus meeting in October 2012. The aim of this process was to agree on how best to supplement the generic standards of the STARD statement to enhance their utility and encourage their use in dementia research.
More than 200 comments were received during the wider consultation rounds. The areas at most risk of inadequate reporting were identified and a set of dementia-specific recommendations to supplement the STARD guidance were developed, including better reporting of patient selection, the reference standard used, avoidance of circularity, and reporting of test-retest reliability.
STARDdem is an implementation of the STARD statement in which the original checklist is elaborated and supplemented with guidance pertinent to studies of cognitive disorders. Its adoption is expected to increase transparency, enable more effective evaluation of diagnostic tests in Alzheimer disease and dementia, contribute to greater adherence to methodologic standards, and advance the development of Alzheimer biomarkers.
The importance of the cholinergic system for cognitive function has been well-documented in animal and human studies. The objective of this study was to elucidate the cognitive and functional connectivity changes associated with enhanced acetylcholine (ACh) levels. We hypothesized older adults with mild memory deficits would show behavioral and functional network enhancements with an acetylcholinesterase inhibitor treatment (donepezil) when compared to a placebo control group.
We conducted a 3-month, double-blind, placebo-controlled study on the effects of donepezil in twenty-seven older adults with mild memory deficits. Participants completed a delayed recognition memory task. FMRI scans were collected at baseline prior to treatment and at 3-month follow-up while on a 10 mg daily dose of donepezil or placebo.
Donepezil treatment significantly enhanced the response time for face and scene memory probes when compared to the placebo group. A group-by-visit interaction was identified for the functional network connectivity of the left fusiform face area (FFA) with the hippocampus and inferior frontal junction, such that the treatment group showed increased connectivity over time when compared to the placebo group. Additionally, the enhanced functional network connectivity of the FFA and hippocampus significantly predicted memory response time at 3-month follow-up in the treatment group.
These findings suggest that increased cholinergic transmission improves goal-directed neural processing and cognitive ability and may serve to facilitate communication across functionally-connected attention and memory networks. Longitudinal fMRI is a useful method for elucidating the neural changes associated with pharmacological modulation and is a potential tool for monitoring intervention efficacy in clinical trials.
Cognitive impairment is common among individuals with heart failure. The purpose of this study was to compare cognitive profiles of individuals with systolic and diastolic dysfunction. Eighty individuals with heart failure completed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Mini-Mental State Examination, Trail Making Test, and letter fluency. Approximately 25% of individuals with systolic dysfunction were impaired on the RBANS Total Scale score, compared with only 3% in the diastolic group. Additionally, individuals with systolic dysfunction scored lower than those with diastolic dysfunction on tests of immediate and delayed memory. The groups did not differ on tests of visuospatial skills, but there were mixed results on the RBANS Attention and Language subtests. Overall, the results of this study suggest that individuals with different types of cardiac dysfunction (systolic and diastolic dysfunction) demonstrate differential patterns of performance on neuropsychological tests. These findings have important clinical implications.
Cardiovascular disease; Executive function; Learning and memory; Mild cognitive impairment; Assessment
The Alzheimer’s Disease Neuroimaging Initiative (ADNI) is a large multi-center study designed to develop optimized methods for acquiring longitudinal neuroimaging, cognitive, and biomarker measures of AD progression in a large cohort of patients with Alzheimer’s disease (AD), patients with mild cognitive impairment, and healthy controls. Detailed neuropsychological testing was conducted on all participants. We examined the factor structure of the ADNI Neuropsychological Battery across older adults with differing levels of clinical AD severity based on the Clinical Dementia Rating Scale (CDR). Confirmatory factor analysis (CFA) of 23 variables from 10 neuropsychological tests resulted in five factors (memory, language, visuospatial functioning, attention, and executive function/processing speed) that were invariant across levels of cognitive impairment. Thus, these five factors can be used as valid indicators of cognitive function in older adults who are participants in ADNI.
ADNI; neuropsychology; cognition; cognitive change; confirmatory factor analysis
Recent changes in diagnostic criteria for Alzheimer’s disease (AD) state that biomarkers can enhance certainty in a diagnosis of AD. In the present study, we combined cognitive function and brain morphology, a potential imaging biomarker, to predict conversion from mild cognitive impairment to AD. We identified four biomarkers, or cortical signatures of cognition (CSC), from regressions of cortical thickness on neuropsychological factors representing memory, executive function/processing speed, language, and visuospatial function among participants in the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Neuropsychological factor scores were created from a previously validated multidimensional factor structure of the neuropsychological battery in ADNI. Mean thickness of each CSC at the baseline study visit was used to evaluate risk of conversion to clinical AD among participants with mild cognitive impairment (MCI) and rate of decline on the Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) score. Of 307 MCI participants, 119 converted to AD. For all domain-specific CSC, a one standard deviation thinner cortical thickness was associated with an approximately 50% higher hazard of conversion and an increase of approximately 0.30 points annually on the CDR-SB. In combined models with a domain-specific CSC and neuropsychological factor score, both CSC and factor scores predicted conversion to AD and increasing clinical severity. As structural magnetic resonance imaging becomes more clinically routine and time-effective than neuropsychological testing, these signatures can be used as biomarkers of conversion to AD andincreasing clinical severity.
MRI; Freesurfer; cortical thickness; ADNI; cognition; brain mapping
To review cognitive impairment and explore current measurement concerns faced by nurse practitioners caring for individuals with heart failure.
Review of peer-reviewed research articles published on the topic.
Cognitive impairment is prevalent among individuals with heart failure. Impairment frequently involves one or more domains, including attention, memory, and executive function. No gold standard screening measure was identified from the reviewed literature.
Implications for practice
It is imperative that clinicians are aware of cognitive impairment and its implications for their patients with heart failure. Cognitive impairment likely contributes to multiple clinical implications, including a decreased ability to attend to and comprehend patient education materials and an inability to appropriately assess and self-manage symptoms.
Heart failure; cognitive impairment; neuroscience; assessment; review
The goal of the current study was to examine cognitive change in both healthy controls (n=229) and individuals with mild cognitive impairment (MCI) (n=397) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). We applied latent growth modeling to examine baseline and longitudinal change over 36 months in five cognitive factors derived from the ADNI neuropsychological test battery (memory, executive function/processing speed, language, attention and visuospatial). At baseline, MCI patients demonstrated lower performance on all of the five cognitive factors when compared to controls. Both controls and MCI patients declined on memory over 36 months; however, the MCI patients declined at a significantly faster rate than controls. The MCI patients also declined over 36 months on the remaining four cognitive factors. In contrast, the controls did not exhibit significant change over 36 months on the non-memory cognitive factors. Within the MCI group, executive function declined faster than memory, while the other factor scores changed slower than memory over time. These findings suggest different patterns of cognitive change in healthy older adults and MCI patients. The findings also suggest that, when compared with memory, executive function declines faster than other cognitive factors in patients with MCI. Thus, decline in non-memory domains may be an important feature for distinguishing healthy older adults and persons with MCI.
ADNI; Neuropsychology; Cognition; Mild cognitive impairment; Cognitive change; Executive function
Based on the recent literature and collective experience, an international consortium developed revised guidelines for the diagnosis of behavioural variant frontotemporal dementia. The validation process retrospectively reviewed clinical records and compared the sensitivity of proposed and earlier criteria in a multi-site sample of patients with pathologically verified frontotemporal lobar degeneration. According to the revised criteria, ‘possible’ behavioural variant frontotemporal dementia requires three of six clinically discriminating features (disinhibition, apathy/inertia, loss of sympathy/empathy, perseverative/compulsive behaviours, hyperorality and dysexecutive neuropsychological profile). ‘Probable’ behavioural variant frontotemporal dementia adds functional disability and characteristic neuroimaging, while behavioural variant frontotemporal dementia ‘with definite frontotemporal lobar degeneration’ requires histopathological confirmation or a pathogenic mutation. Sixteen brain banks contributed cases meeting histopathological criteria for frontotemporal lobar degeneration and a clinical diagnosis of behavioural variant frontotemporal dementia, Alzheimer’s disease, dementia with Lewy bodies or vascular dementia at presentation. Cases with predominant primary progressive aphasia or extra-pyramidal syndromes were excluded. In these autopsy-confirmed cases, an experienced neurologist or psychiatrist ascertained clinical features necessary for making a diagnosis according to previous and proposed criteria at presentation. Of 137 cases where features were available for both proposed and previously established criteria, 118 (86%) met ‘possible’ criteria, and 104 (76%) met criteria for ‘probable’ behavioural variant frontotemporal dementia. In contrast, 72 cases (53%) met previously established criteria for the syndrome (P < 0.001 for comparison with ‘possible’ and ‘probable’ criteria). Patients who failed to meet revised criteria were significantly older and most had atypical presentations with marked memory impairment. In conclusion, the revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotemporal lobar degeneration. Greater sensitivity of the proposed criteria may reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations. Future studies will be needed to establish the reliability and specificity of these revised diagnostic guidelines.
behavioural variant frontotemporal dementia; diagnostic criteria; frontotemporal lobar degeneration; FTD; pathology
Although early studies on mild cognitive impairment (MCI) focused on memory dysfunction; more recent studies suggest that MCI is clinically heterogeneous. The objective of this study is to examine patterns of cerebral perfusion in anmestic (N=12) and non-amnestic (N=12) single-domain MCI patients from four a priori regions of interest (ROI): middle and superior frontal cortex, posterior cingulate, and precuneus, to compare them relative to healthy controls (N=12), and to correlate perfusion with neuropsychological measures. Relative to controls, all MCI patients had hypoperfusion in the posterior cingulate, bilaterally. MCI patients with executive dysfunctions also showed hypoperfusion in bilateral middle frontal cortex and the left precuneus relative to controls and in the left middle frontal cortex, left posterior cingulate, and left precuneus relative to amnestic MCI patients. Perfusion in the posterior cingulate correlated positively with memory performance while perfusion in all four a priori ROIs, predominately on the left side, correlated with executive function performance. The finding that single-domain MCI patients with prominent deficits in different cognitive domains exhibited different patterns of hypoperfusion relative to controls supports the existence of distinct subgroups of MCI. These data further suggest that cognitive impairment in MCI is related to cerebral hypoperfusion.
There is increasing recognition that set-shifting, a form of cognitive control, is mediated by different neural structures. However, these regions have not yet been carefully identified as many studies do not account for the influence of component processes (e.g., motor speed). We investigated gray matter correlates of set-shifting while controlling for component processes. Using the Design Fluency (DF), Trail Making Test (TMT), and Color Word Interference (CWI) subtests from the Delis-Kaplan Executive Function System (D-KEFS), we investigated the correlation between set-shifting performance and gray matter volume in 160 subjects with neurodegenerative disease, mild cognitive impairment, and healthy older adults using voxel-based morphometry. All three set-shifting tasks correlated with multiple, widespread gray matter regions. After controlling for the component processes, set-shifting performance correlated with focal regions in prefrontal and posterior parietal cortices. We also identified bilateral prefrontal cortex and the right posterior parietal lobe as common sites for set-shifting across the three tasks. There was a high degree of multicollinearity between the set-shifting conditions and the component processes of TMT and CWI, suggesting DF may better isolate set-shifting regions. Overall, these findings highlight the neuroanatomical correlates of set-shifting and the importance of controlling for component processes when investigating complex cognitive tasks.
D-KEFS; Design fluency; Trail making test; Color word interference; Executive function; Voxel-based morphometry
Good cognitive performance requires adherence to rules specific to the task at hand. Patients with neurological disease often make rule violation errors, but the anatomical basis for rule violation during cognitive testing remains debated. The current study examined the neuroanatomical correlates of rule violation (RV) errors made on tests of executive functioning in 166 subjects diagnosed with neurodegenerative disease or as neurologically healthy. Specifically, RV errors were voxel-wisely correlated with gray matter volume derived from high-definition MR images using voxel-based morphometry implemented in SPM2. Latent variable analysis showed that rule violation errors tapped a unitary construct separate from repetition errors. This analysis was used to generate factor scores to represent what is common among rule violation errors across tests. The extracted rule violation factor scores correlated with tissue loss in the lateral middle and inferior frontal gyri and the caudate nucleus bilaterally. When a more stringent control for global cognitive functioning was applied using Mini Mental State Exam scores, only the correlations with the right lateral prefrontal cortex remained significant. These data underscore the importance of right lateral prefrontal cortex in behavioral monitoring and highlight the potential of rule violation error assessment for identifying patients with damage to this region.
cognitive control; neuropsychological assessment; executive functioning; voxel-based morphometry; inhibition; frontal lobe
To determine if more widespread cognitive deficits are present in a narrowly defined group of patients with the amnestic form of mild cognitive impairment (MCI).
From a larger sample of patients clinically diagnosed as meeting the criteria of Petersen et al. for amnestic MCI, we selected 22 subjects who had Clinical Dementia Rating scores of zero on all domains besides memory and orientation. These MCI subjects with presumably isolated memory impairments were compared to 35 age-matched normal controls and 33 very mild Alzheimer's disease (AD) patients on a battery of neuropsychological tests.
In addition to the expected deficits in episodic memory, the amnestic MCI group performed less well than the controls but better than the AD group on design fluency, category fluency, a set shifting task and the Stroop interference condition. Over half the amnestic MCI group (vs. none of the normal controls) scored at least 1 standard deviation below control means on 4 or more of the nonmemory cognitive tasks.
Isolated memory impairment may be fairly uncommon in clinically diagnosed amnestic MCI patients, even when the criteria for amnestic MCI are fairly narrow. Additional cognitive impairments are likely to include fluency and executive functioning. These more diffuse deficits argue for comprehensive cognitive assessments, even when the patient and family are reporting only memory decline, and are consistent with the increase in attention paid to the heterogeneity of MCI.
Amnestic mild cognitive impairment; Alzheimer's disease; Executive function; Fluency
Frontotemporal lobar degeneration (FTLD) is characterized by impairments in social, behavioral, and/or language function, but postmortem studies indicate that multiple neuropathological entities lead to FTLD. This study assessed whether specific clinical features predict the underlying pathology.
A clinicopathological correlation was performed on 90 consecutive patients with a pathological diagnosis of frontotemporal dementia and was compared with an additional 24 cases accrued during the same time period with a clinical diagnosis of FTLD, but with pathology not typically associated with frontotemporal dementia.
Postmortem examination showed multiple pathologies including tauopathies (46%), FTLD with ubiquitin-positive inclusions (29%), and Alzheimer’s disease (17%). The pathological groups manifested some distinct demographic, clinical, and neuropsychological features, although these attributes showed only a statistical association with the underlying pathology. FTLD with ubiquitin-positive inclusions was more likely to present with both social and language dysfunction, and motor neuron disease was more likely to emerge in these patients. Tauopathies were more commonly associated with an extrapyramidal disorder. Alzheimer’s disease was associated with relatively greater deficits in memory and executive function.
Clinical and neuropsychological features contribute to delineating the spectrum of pathology underlying a patient diagnosed with FTLD, but biomarkers are needed that, together with the clinical phenotype, can predict the underlying neuropathology.
We performed a comprehensive cognitive, neuroimaging, and genetic study of 31 patients with primary progressive aphasia (PPA), a decline in language functions that remains isolated for at least 2 years. Detailed speech and language evaluation was used to identify three different clinical variants: nonfluent progressive aphasia (NFPA; n = 11), semantic dementia (SD; n = 10), and a third variant termed logopenic progressive aphasia (LPA; n = 10). Voxel-based morphometry (VBM) on MRIs showed that, when all 31 PPA patients were analyzed together, the left perisylvian region and the anterior temporal lobes were atrophied. However, when each clinical variant was considered separately, distinctive patterns emerged: (1) NFPA, characterized by apraxia of speech and deficits in processing complex syntax, was associated with left inferior frontal and insular atrophy; (2) SD, characterized by fluent speech and semantic memory deficits, was associated with anterior temporal damage; and (3) LPA, characterized by slow speech and impaired syntactic comprehension and naming, showed atrophy in the left posterior temporal cortex and inferior parietal lobule. Apolipoprotein E ε4 haplotype frequency was 20% in NFPA, 0% in SD, and 67% in LPA. Cognitive, genetic, and anatomical features indicate that different PPA clinical variants may correspond to different underlying pathological processes.
Frontotemporal lobar degeneration (FTLD) often overlaps clinically with corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP), both of which have prominent eye movement abnormalities. To investigate the ability of oculomotor performance to differentiate between FTLD, Alzheimer's disease, CBS and PSP, saccades and smooth pursuit were measured in three FTLD subtypes, including 24 individuals with frontotemporal dementia (FTD), 19 with semantic dementia (SD) and six with progressive non-fluent aphasia (PA), as compared to 28 individuals with Alzheimer's disease, 15 with CBS, 10 with PSP and 27 control subjects. Different combinations of oculomotor abnormalities were identified in all clinical syndromes except for SD, which had oculomotor performance that was indistinguishable from age-matched controls. Only PSP patients displayed abnormalities in saccade velocity, whereas abnormalities in saccade gain were observed in PSP > CBS > Alzheimer's disease subjects. All patient groups except those with SD were impaired on the anti-saccade task, however only the FTLD subjects and not Alzheimer's disease, CBS or PSP groups, were able to spontaneously self-correct anti-saccade errors as well as controls. Receiver operating characteristic statistics demonstrated that oculomotor findings were superior to neuropsychological tests in differentiating PSP from other disorders, and comparable to neuropsychological tests in differentiating the other patient groups. These data suggest that oculomotor assessment may aid in the diagnosis of FTLD and related disorders.
oculomotor; frontotemporal lobar degeneration; corticobasal syndrome; progressive supranuclear palsy; Alzheimer's disease