Neuropsychological correlates of dominance, warmth, and extraversion in neurodegenerative disease.

INTRODUCTION: Changes in personality differ qualitatively and quantitatively among patients with different neurodegenerative diseases, likely due to divergent patterns of regional neurodegeneration. Regional damage to circuits underlying various cognitive and emotional functions have been associated with interpersonal traits like dominance, extraversion, and warmth in patients with neurodegenerative diseases, suggesting that personality may in part be mediated by these more basic neuropsychological functions. In this study, we hypothesized that different combinations of cognitive, neuropsychiatric, and emotional measures would predict different interpersonal traits in patients with neurodegenerative diseases. METHODS: A battery of cognitive, neuropsychiatric, and emotional measures was administered to 286 patients with various neurodegenerative diseases such as Alzheimer's disease, behavioral variant frontotemporal dementia, semantic dementia, and progressive supranuclear palsy, and informants described patients' dominance, extraversion, and warmth using the Interpersonal Adjective Scales (IAS) personality questionnaire. Regression modeling was performed to identify which neuropsychological factors uniquely predicted current personality, controlling for age, gender, and premorbid personality. RESULTS: Social dominance covaried with patients' capacity for cognitive control and verbal fluency. Conversely, warmth did not rely on these executive or verbal skills, but covaried primarily with patients' capacity for emotional responsiveness. Extraversion, representing a blend of dominance and warmth, demonstrated an intermediate degree of relationship to both executive/verbal and emotional functions. CONCLUSIONS: These findings suggest that different personality traits are partly subserved by specific cognitive and emotional functions in neurodegenerative disease patients. While this study was performed in the context of brain damage, the results raise the question of whether individual differences in these neuropsychological abilities may also underlie variability in normal personality.

Interpersonal traits change as a function of disease type and severity in degenerative brain diseases.

BACKGROUND: Different degenerative brain diseases result in distinct personality changes as a result of divergent patterns of brain damage; however, little is known about the natural history of these personality changes throughout the course of each disease. OBJECTIVE: To investigate how interpersonal traits change as a function of degenerative brain disease type and severity. METHODS: Using the Interpersonal Adjective Scales, informant ratings of retrospective premorbid and current scores for dominance, extraversion, warmth and ingenuousness were collected annually for 1 to 4 years on 188 patients (67 behavioural variant frontotemporal dementia (bvFTD), 40 semantic dementia (SemD), 81 Alzheimer's disease (AD)) and 65 older healthy controls. Using random coefficient models, interpersonal behaviour scores at very mild, mild or moderate-to-severe disease stages were compared within and between patient groups. RESULTS: Group-level changes from premorbid personality occurred as a function of disease type and severity, and were apparent even at a very mild disease stage (Clinical Dementia Rating=0.5) for all three diseases. Decreases in interpersonal traits were associated with emotional affiliation (ie, extraversion, warmth and ingenuousness) and more rigid interpersonal behaviour differentiated bvFTD and SemD patients from AD patients. CONCLUSIONS: Specific changes in affiliative interpersonal traits differentiate degenerative brain diseases even at a very mild disease stage, and patterns of personality change differ across bvFTD, SemD and AD with advancing disease. This study describes the typical progression of change of interpersonal traits in each disease, improving the ability of clinicians and caregivers to predict and plan for symptom progression.

Neural basis of interpersonal traits in neurodegenerative diseases.

Several functional and structural imaging studies have investigated the neural basis of personality in healthy adults, but human lesions studies are scarce. Personality changes are a common symptom in patients with neurodegenerative diseases like frontotemporal dementia (FTD) and semantic dementia (SD), allowing a unique window into the neural basis of personality. In this study, we used the Interpersonal Adjective Scales to investigate the structural basis of eight interpersonal traits (dominance, arrogance, coldness, introversion, submissiveness, ingenuousness, warmth, and extraversion) in 257 subjects: 214 patients with neurodegenerative diseases such as FTD, SD, progressive nonfluent aphasia, Alzheimer's disease, amnestic mild cognitive impairment, corticobasal degeneration, and progressive supranuclear palsy and 43 healthy elderly people. Measures of interpersonal traits were correlated with regional atrophy pattern using voxel-based morphometry (VBM) analysis of structural MR images. Interpersonal traits mapped onto distinct brain regions depending on the degree to which they involved agency and affiliation. Interpersonal traits high in agency related to left dorsolateral prefrontal and left lateral frontopolar regions, whereas interpersonal traits high in affiliation related to right ventromedial prefrontal and right anteromedial temporal regions. Consistent with the existing literature on neural networks underlying social cognition, these results indicate that brain regions related to externally focused, executive control-related processes underlie agentic interpersonal traits such as dominance, whereas brain regions related to internally focused, emotion- and reward-related processes underlie affiliative interpersonal traits such as warmth. In addition, these findings indicate that interpersonal traits are subserved by complex neural networks rather than discrete anatomic areas.

Left frontal lobe contributions to concept formation: a quantitative MRI study of performance on the Delis-Kaplan Executive Function System Sorting Test.

This study examined relationships between lobar volumes and performance on the Delis-Kaplan Executive Function System (D-KEFS) Sorting Test, a standardized measure of concept formation. There were 89 participants: 19 patients with probable Alzheimer's disease, 25 patients with frontotemporal dementia, 13 patients with semantic dementia, 12 patients with progressive nonfluent aphasia, 9 patients with probable progressive supranuclear palsy, 2 patients with possible progressive supranuclear palsy, and 9 healthy participants. We used BRAINS2 software to generate volumes of the right and left frontal, temporal, and parietal lobes. Multiple regression analysis indicated that, after controlling for Mini-Mental State Examination scores, intracranial volume, and demographic variables, only the left frontal lobe significantly predicted performance on the D-KEFS Sorting Test.

Spontaneous social behaviors discriminate behavioral dementias from psychiatric disorders and other dementias.

OBJECTIVE: Changes in social behavior are often the first symptoms of neurodegenerative disease. Patients with frontotemporal lobar degeneration (FTLD) often go undiagnosed, or are misclassified as psychiatric patients, because in the absence of cognitive deficits, nonexperts fail to recognize these social changes as dementia symptoms. The object of this study was to improve screening for behavioral dementias in primary care and mental health settings by quantifying spontaneous social behaviors specific to FTLD. METHOD: In a university hospital dementia clinic, examiners blind to subject diagnosis performed 1 hour of cognitive testing, then completed the Interpersonal Measure of Psychopathy, an 18-item checklist of observed inappropriate behaviors. Patients then underwent a multidisciplinary evaluation to derive a neurodegenerative or psychiatric diagnosis. Data were collected from 288 subjects: 45 Alzheimer's disease (National Institute of Neurologic and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association research criteria); 40 frontotemporal dementia, 21 semantic dementia, and 13 progressive nonfluent aphasia (Neary research criteria); 14 corticobasal degeneration and 21 progressive supranuclear palsy (Litvan research criteria); 37 dementia with Lewy bodies (McKeith research criteria); 16 vascular dementia (Ischemic Vascular Disease research criteria); 29 mixed vascular and Alzheimer's disease (Alzheimer's Disease Diagnostic and Treatment Centers criteria); and 35 primary psychiatric disorder (DSM-IV) patients and 17 normal older controls. The study was conducted from March 2002 to January 2005. RESULTS: Statistical item analyses demonstrated specific patterns of social behavior that differentiated both frontotemporal dementia and semantic dementia patients from (1) nondementing older adults, (2) nondementing individuals with psychiatric conditions, (3) individuals with cerebrovascular disease, and (4) individuals with other neurodegenerative disorders. Semantic dementia patients verbally and physically interrupted evaluations, spoke perseveratively and tangentially, and resisted clinician redirection. Frontotemporal dementia patients were apathetic or disinhibited and were unconcerned about meeting clinician expectations. CONCLUSION: Specific, abnormal, interpersonal behaviors can alert nonexperts to the need for specialized dementia referral.