The influence of right frontotemporal dysfunction on social behavior in frontotemporal dementia

Behavioral changes in early ALS correlate with voxel-based morphometry and diffusion tensor imaging

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a multisystem disorder with impairment of frontotemporal functions such as cognition and behavior, but the behavioral changes associated with ALS are not well defined.

METHODS

Twenty-one consecutive patients with sporadic ALS and 21 control subjects participated in the study. The Frontal System Behavior Scale (FrSBe) was used to assess behavioral change. Voxel-based morphometry (VBM) and voxel-based analysis of diffusion tensor images (DTI) were performed to explore the associations of brain degeneration with behavior. All patients were evaluated before the notification of ALS.

RESULTS

FrSBe scores of ALS patients before notification were significantly increased compared to those of control subjects. Moreover, the FrSBe Apathy score of ALS patients significantly changed from pre- to post-illness (P<0.001). The severity of apathy was significantly correlated with atrophy in the prefrontal cortex, especially in the orbitofrontal (P=0.006) and dorsolateral prefrontal (P=0.006) cortices in VBM, and in the right frontal gyrus (P<0.001) in DTI.

CONCLUSIONS

ALS patients exhibited apathy during the early course of the illness, the severity of which was significantly associated with frontal lobe involvement. These findings support the view that a continuum exits between ALS and frontotemporal dementia.

New potential therapeutic approaches in frontotemporal dementia: oxytocin, vasopressin, and social cognition

Frontotemporal dementias are neurodegenerative disorders marked by mid-life onset and progressive changes in behavior, decision making, and/or language. In several subtypes of frontotemporal dementia (FTD), damage to regions of the frontal and temporal lobes that occurs early in the disease course critically impairs emotional processing, social cognition, and behavior. To date, there are no curative or disease-modifying treatments for FTD, nor any approved treatments for the loss of empathy, impaired social cognition, and behavior of patients with FTD. A growing body of research suggests that the neuropeptides oxytocin and vasopressin are important mediators of social behavior in humans and other animals. Here, we review the effects of oxytocin and vasopressin on social cognition and behavior and discuss the potential implications for these agents as novel treatments in FTD.

Double dissociation in the anatomy of socioemotional disinhibition and executive functioning in dementia

OBJECTIVE

To determine whether socioemotional disinhibition and executive dysfunction are related to dissociable patterns of brain atrophy in neurodegenerative disease. Previous studies have indicated that behavioral and cognitive dysfunction in neurodegenerative disease are linked to atrophy in different parts of the frontal lobes, but these prior studies did not establish that these relationships were specific, which would best be demonstrated by a double dissociation.

METHOD

Subjects included 157 patients with neurodegenerative disease. A semiautomated parcellation program (Freesurfer) was used to generate regional cortical volumes from structural MRI scans. Regions of interest (ROIs) included anterior cingulate cortex (ACC), orbitofrontal cortex (OFC), middle frontal gyrus (MFG), and inferior frontal gyrus (IFG). Socioemotional disinhibition was measured using the Neuropsychiatric Inventory. Principal component analysis including 3 tasks of executive function (EF; verbal fluency, Stroop Interference, modified Trails) was used to generate a single-factor score to represent EF.

RESULTS

Partial correlations between ROIs, disinhibition, and EF were computed after controlling for total intracranial volume, Mini-Mental State Examination, diagnosis, age, and education. Brain regions significantly correlated with disinhibition (ACC, OFC, IFG, and temporal lobes) and EF (MFG) were entered into separate hierarchical regressions to determine which brain regions predicted disinhibition and EF. OFC was the only brain region to significantly predict disinhibition, and MFG significantly predicted EF performance. A multivariate general linear model demonstrated a significant interaction between ROIs and cognitive-behavioral functions.

CONCLUSIONS

These results support a specific association between orbitofrontal areas and behavioral management as compared with dorsolateral areas and EF.

Who's afraid of the boss: cultural differences in social hierarchies modulate self-face recognition in Chinese and Americans

Human adults typically respond faster to their own face than to the faces of others. However, in Chinese participants, this self-face advantage is lost in the presence of one's supervisor, and they respond faster to their supervisor's face than to their own. While this "boss effect" suggests a strong modulation of self-processing in the presence of influential social superiors, the current study examined whether this effect was true across cultures. Given the wealth of literature on cultural differences between collectivist, interdependent versus individualistic, independent self-construals, we hypothesized that the boss effect might be weaker in independent than interdependent cultures. Twenty European American college students were asked to identify orientations of their own face or their supervisors' face. We found that European Americans, unlike Chinese participants, did not show a "boss effect" and maintained the self-face advantage even in the presence of their supervisor's face. Interestingly, however, their self-face advantage decreased as their ratings of their boss's perceived social status increased, suggesting that self-processing in Americans is influenced more by one's social status than by one's hierarchical position as a social superior. In addition, when their boss's face was presented with a labmate's face, American participants responded faster to the boss's face, indicating that the boss may represent general social dominance rather than a direct negative threat to oneself, in more independent cultures. Altogether, these results demonstrate a strong cultural modulation of self-processing in social contexts and suggest that the very concept of social positions, such as a boss, may hold markedly different meanings to the self across Western and East Asian cultures.

Brain morphometry and functional imaging techniques in dementia: methods, findings and relevance in forensic neurology

PURPOSE OF REVIEW

The ability to predict what people perceive from patterns of brain activity raises futuristic questions. Amongst these are questions about the role of brain activity in predicting misdemeanours or preventing them. Two obvious cases in point are the tendency of some patients with fronto-temporal lobar degeneration to become aggressive and the difficulty deciding when Alzheimer patients need to stop driving for reasons of safety. These two situations will be used to structure a review of the literature in this general area.

RECENT FINDINGS

Multivariate classification techniques (MCT) improve early accurate diagnosis of dementia. Given the known frequency of behavioural abnormalities, this information allows better prediction of the future frequency of such behaviour. In addition, MCT could prove suitable for providing reasonably accurate information of relevance to individuals about the combination of future symptoms. However, no study has applied MCT to the prediction of future behavioural problems or to assessments of road safety in dementia.

SUMMARY

MCT could improve the prediction of offensive or risky behaviour in which standard neuropsychological testing is less than conclusive. Cognitive function in multiple domains, as required for driving, is likely to be best examined using well established neuropsychological tests and possibly driving simulators.

The influence of tobacco consumption on the relationship between schizotypy and hemispheric asymmetry

Tobacco use is positively associated with severity of symptoms along the schizophrenia spectrum. Accordingly it could be argued that neuropsychological performance, formerly thought to be modulated by schizotypy, is actually modulated by drug use or an interaction of drug use and schizotypy. We tested whether habitual cigarette smokers as compared to non-smokers would show a neuropsychological profile similar to that observed along the schizophrenia spectrum and, if so, whether smoking status or nicotine dependence would be more significant modulators of behavior than schizotypy. Because hemispheric dominance has been found to be attenuated along the schizophrenia spectrum, 40 right-handed male students (20 non-smokers) performed lateralized left- (lexical decisions) and right- (facial decision task) hemisphere dominant tasks. All individuals completed self-report measures of schizotypy and nicotine dependence. Schizotypy predicted laterality in addition to smoking status: While positive schizotypy (Unusual Experiences) was unrelated to hemispheric performance, Cognitive Disorganization predicted reduced left hemisphere dominant language functions. These latter findings suggest that Cognitive Disorganization should be regarded separately as a potentially important mediator of thought disorganization and language processing. Additionally, increasing nicotine dependence among smokers predicted a right hemisphere shift of function in both tasks that supports the role of the right hemisphere in compulsive/impulsive behavior.

The role of ventral medial prefrontal cortex in social decisions: converging evidence from fMRI and frontotemporal lobar degeneration

The ventral medial prefrontal cortex (vmPFC) has been implicated in social and affectively influenced decision-making. Disease in this region may have clinical consequences for social judgments in patients with frontotemporal lobar degeneration (FTLD). To test this hypothesis, regional cortical activation was monitored with fMRI while healthy adults judged the acceptability of brief social scenarios such as cutting into a movie ticket line or going through a red light at 2 AM. The scenarios described: (i) a socially neutral condition, (ii) a variant of each scenario containing a negatively valenced feature, and (iii) a variant containing a positively valenced feature. Results revealed that healthy adults activated vmPFC during judgments of negatively valenced scenarios relative to positive scenarios and neutral scenarios. In a comparative behavioral study, the same social decision-making paradigm was administered to patients with a social disorder due to FTLD. Patients differed significantly from healthy controls, specifically showing less sensitivity to negatively valenced features. Comparative anatomical analysis revealed considerable overlap of vmPFC activation in healthy adults and vmPFC cortical atrophy in FTLD patients. These converging results support the role of vmPFC in social decision-making where potentially negative consequences must be considered.

Frontotemporal lobar degeneration: epidemiology, pathophysiology, diagnosis and management

Frontotemporal lobar degeneration (FTLD) is a clinically and pathologically heterogeneous syndrome, characterized by progressive decline in behaviour or language associated with degeneration of the frontal and anterior temporal lobes. While the seminal cases were described at the turn of the 20th century, FTLD has only recently been appreciated as a leading cause of dementia, particularly in patients presenting before the age of 65 years. Three distinct clinical variants of FTLD have been described: (i) behavioural-variant frontotemporal dementia, characterized by changes in behaviour and personality in association with frontal-predominant cortical degeneration; (ii) semantic dementia, a syndrome of progressive loss of knowledge about words and objects associated with anterior temporal neuronal loss; and (iii) progressive nonfluent aphasia, characterized by effortful language output, loss of grammar and motor speech deficits in the setting of left perisylvian cortical atrophy. The majority of pathologies associated with FTLD clinical syndromes include either tau-positive (FTLD-TAU) or TAR DNA-binding protein 43 (TDP-43)-positive (FTLD-TDP) inclusion bodies. FTLD overlaps clinically and pathologically with the atypical parkinsonian disorders corticobasal degeneration and progressive supranuclear palsy, and with amyotrophic lateral sclerosis. The majority of familial FTLD cases are caused by mutations in the genes encoding microtubule-associated protein tau (leading to FTLD-TAU) or progranulin (leading to FTLD-TDP). The clinical and pathological heterogeneity of FTLD poses a significant diagnostic challenge, and in vivo prediction of underlying histopathology can be significantly improved by supplementing the clinical evaluation with genetic tests and emerging biological markers. Current pharmacotherapy for FTLD focuses on manipulating serotonergic or dopaminergic neurotransmitter systems to ameliorate behavioural or motor symptoms. However, recent advances in FTLD genetics and molecular pathology make the prospect of biologically driven, disease-specific therapies for FTLD seem closer than ever.

Temporal pole activity during understanding other persons' mental states correlates with neuroticism trait

Comprehension of other persons' mental states is one of the representative cognitive functions involved in social situations. It has been suggested that this function sometimes recruits emotional processes. The present fMRI study examined the neural mechanisms associated with understanding others' mental states, and the conditions that determine the recruitment of the emotional processes. The false belief paradigm, a traditional behavioral paradigm to investigate comprehension of others, was applied to an event-related fMRI analysis, allowing for the extraction of brain activity time-locked to successful understanding of others' mental states. Prominent brain activity was observed in multiple cortical regions including the medial prefrontal cortex, temporo-parietal junction, precuneus, and temporal pole. Then, correlational analyses were performed between the activations and individuals' scores of neuroticism, a personality trait that reflects emotional instability in daily life. It was revealed that the neuroticism scores were positively correlated with the activity in the temporal pole region, but not in the other regions. These results suggest that the emotional processes implemented in the temporal pole are recruited during successful understanding of other persons' mental states, and that the recruitment may be modulated by an emotional personality trait of individual subjects.

Social cognition and the anterior temporal lobes

Two distinct literatures have emerged on the functionality of the anterior temporal lobes (ATL): in one field, the ATLs are conceived of as a repository for semantic or conceptual knowledge. In another field, the ATLs are thought to play some undetermined role in social-emotional functions such as Theory of Mind. Here we attempted to reconcile these distinct functions by assessing whether social semantic processing can explain ATL activation in other social cognitive tasks. Social semantic functions refer to knowledge about social concepts and rules. In a first experiment we tested the idea that social semantic representations can account for activations in the ATL to social attribution stimuli such as Heider and Simmel animations. Left ATL activations to Heider and Simmel stimuli overlapped with activations to social words. In a second experiment we assessed the putative roles of the ATLs in the processing of narratives and theory of mind content and found evidence for a role of the ATLs in the processing of theory of mind but not narrative per se. These findings indicate that the ATLs are part of a neuronal network supporting social cognition and that they are engaged when tasks demand access to social conceptual knowledge.

A neural marker of costly punishment behavior

Human readiness to incur personal costs to punish norm violators is a key force in the maintenance of social norms. The willingness to punish is, however, characterized by vast individual heterogeneity that is poorly understood. In fact, this heterogeneity has so far defied explanations in terms of individual-level demographic or psychological variables. Here, we use resting electroencephalography, a stable measure of individual differences in cortical activity, to show that a highly specific neural marker--baseline cortical activity in the right prefrontal cortex--predicts individuals' punishment behavior. The analysis of task-independent individual variation in cortical baseline activity provides a new window into the neurobiology of decision making by bringing dispositional neural markers to the forefront of the analysis.

The neurobiology of moral behavior: review and neuropsychiatric implications

Morality may be innate to the human brain. This review examines the neurobiological evidence from research involving functional magnetic resonance imaging of normal subjects, developmental sociopathy, acquired sociopathy from brain lesions, and frontotemporal dementia. These studies indicate a "neuromoral" network for responding to moral dilemmas centered in the ventromedial prefrontal cortex and its connections, particularly on the right. The neurobiological evidence indicates the existence of automatic "prosocial" mechanisms for identification with others that are part of the moral brain. Patients with disorders involving this moral network have attenuated emotional reactions to the possibility of harming others and may perform sociopathic acts. The existence of this neuromoral system has major clinical implications for the management of patients with dysmoral behavior from brain disorders and for forensic neuropsychiatry.

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.

Depression in frontotemporal dementia

OBJECTIVE

The authors describe mood abnormalities seen in a case series of patients with frontotemporal dementia (FTD).

METHOD

Authors provide a structured review of outpatient and inpatient charts of FTD patients.

RESULTS

Three distinct depressive syndromes were identified: The first corresponds to DSM-IV major depression. The second is a syndrome of mood lability with prominent responsiveness to the environment. The third is a syndrome of profound apathy, without other evidence of depression.

CONCLUSION

A variety of mood disorders are seen in FTD, requiring careful attention to differential diagnosis. FTD should be included in the differential diagnosis during the evaluation of older patients with mood abnormalities.

PREFRONTAL SYSTEM DYSFUNCTION AND CREDIT CARD DEBT

Credit card use often involves a disadvantageous allocation of finances because they allow for spending beyond means and buying on impulse. Accordingly they are associated with increased bankruptcy, anxiety, stress, and health problems. Mounting evidence from functional neuroimaging and clinical studies implicates prefrontal-subcortical systems in processing financial information. This study examined the relationship of credit card debt and executive functions using the Frontal System Behavior Scale (FRSBE). After removing the influences of demographic variables (age, sex, education, and income), credit card debt was associated with the Executive Dysfunction scale, but not the Apathy or Disinhibition scales. This suggests that processes of conceptualizing and organizing finances are most relevant to credit card debt, and implicates dorsolateral prefrontal dysfunction.

A case study of an emerging visual artist with frontotemporal lobar degeneration and amyotrophic lateral sclerosis

Patients presenting with left-sided FTLD syndromes sometimes develop a new preoccupation with art, greater attention to visual stimuli, and increased visual creativity. We describe the case of a 53-year-old, right-handed man with a history of bipolar disorder who presented with language and behavior impairments characteristic of FTLD, then developed motor symptoms consistent with a second diagnosis of amyotrophic lateral sclerosis. Though the patient had never created visual art before, he developed a compulsion for painting beginning at the earliest stages of his disease, and continued producing art daily until he could no longer lift a paintbrush because of his motor deficits. Upon autopsy, he was found to have ubiquitin and TDP43-positive inclusions with MND pathology. This case study details the patient's longitudinal neuropsychological, emotional, behavioral, and motor symptoms, along with structural imaging, neurologic, and neuropathologic findings. Multiple examples of the patient's art are depicted throughout all stages of his illness, and the possible cognitive, behavioral, and neurologic correlates of his new-onset visual artistry are discussed.

Rule violation errors are associated with right lateral prefrontal cortex atrophy in neurodegenerative disease

Good cognitive performance requires adherence to rules specific to the task at hand. Patients with neurological disease often make rule violation (RV) errors, but the anatomical basis for RV during cognitive testing remains debated. The present study examined the neuroanatomical correlates of 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 magnetic resonance images using voxel-based morphometry implemented in SPM2. Latent variable analysis showed that RV errors tapped a unitary construct separate from repetition errors. This analysis was used to generate factor scores to represent what is common among RV errors across tests. The extracted RV 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 (PFC) remained significant. These data underscore the importance of right lateral PFC in behavioral monitoring and highlight the potential of RV error assessment for identifying patients with damage to this region.

Understanding social dysfunction in the behavioural variant of frontotemporal dementia: the role of emotion and sarcasm processing

Social interaction is profoundly affected in the behavioural form of frontotemporal dementia (bvFTD) yet there are few means of objectively assessing this. Diagnosis of bvFTD is based on informant report, however a number of individuals with a clinical profile consistent with the disease have no imaging abnormality and seem to remain stable, with doubt about the presence of underlying neurodegenerative pathology. We aimed to quantify aspects of the behavioural disorder and link it to the underlying level of atrophy in socially relevant brain regions. We tested individuals with either bvFTD (N = 26) or Alzheimer's disease (N = 9) and 16 controls using The Awareness of Social Inference Test (TASIT) to assess their ability to identify emotion and sarcasm in video vignettes. A subset of bvFTD patients (N = 21) and controls (N = 12) were scanned using MRI within 6 months of assessment. There was marked impairment in the ability of bvFTD patients whose scans showed abnormalities to recognize sarcastic, but not sincere statements. Their capacity to interpret negative emotion was also impaired, and this appeared to be a major factor underlying the deficit in sarcasm recognition. Clinically diagnosed bvFTD patients whose scans were normal, Alzheimer's disease patients and controls had no difficulty in appreciating both types of statement. In a multivariate imaging analysis it was shown that the sarcasm (and emotion recognition) deficit was dependent on a circuit involving the lateral orbitofrontal cortex, insula, amygdala and temporal pole, particularly on the right. Performance on a more global test of cognitive function, the Addenbrooke's Cognitive Examination did not have a unique association with these regions. The TASIT is an objective test of social dysfunction in bvFTD which indexes the frontotemporal volume loss in bvFTD patients and provides an objective measure for separating behavioural patients who are likely to decline from those who may remain stable. These results provide additional evidence for the role of the orbitofrontal cortex and related structures in the processing of socially relevant signals, particularly those where negative emotion recognition is important.

Neuroanatomy of apathy and disinhibition in frontotemporal lobar degeneration

OBJECTIVE

To investigate the neural basis for the behavioral symptoms of frontotemporal lobar degeneration (FTLD) that cause the greatest caregiver distress.

BACKGROUND

FTLD is a progressive neurodegenerative disease associated with behavioral disturbances. Group studies have related these behaviors to volume loss on MRI.

METHODS

Forty caregivers of patients with the clinical diagnosis of FTLD completed the Neuropsychiatric Inventory. Twelve neuropsychiatric symptoms and the associated caregiver distress were assessed. Optimized voxel-based morphometry identified significant atrophy in subgroups of FTLD patients with isolated behavioral symptoms corresponding to the most distressing behaviors, and we correlated cortical atrophy directly with these distressing behavioral disorders in an unbiased group analysis.

RESULTS

The greatest stressors for caregivers were apathy and disinhibition (p < 0.005 for both contrasts). Partially distinct areas of cortical atrophy were associated with these behaviors in both individual patients with these symptoms and group-wide analyses, including the dorsal anterior cingulate cortex and dorsolateral prefrontal cortex in apathetic patients, and the medial orbital frontal cortex in disinhibited patients.

CONCLUSIONS

Caregiver stress in families of FTLD patients is due in large part to apathy and disinhibition. The anatomic distribution of cortical loss corresponding to these distressing social behaviors includes partially distinct areas within the frontal lobe.

Apathy and disinhibition in frontotemporal dementia: Insights into their neural correlates

BACKGROUND

Aberrant social behavior is a defining symptom of frontotemporal dementia (FTD) and may eventually occur in all syndromes composing the FTD spectrum. Two main behavioral abnormalities have been described: apathy and disinhibition, but their neuroanatomical correlates remain underspecified.

METHODS

Sixty-two patients with a clinical diagnosis of FTD participated in the study. Voxel-based morphometry of MRI data was performed to explore the association between gray matter loss and severity of the two behavioral profiles as measured by the Apathy and Disinhibition subscales of the Frontal Systems Behavior Scale.

RESULTS

Compared with a group of controls, the FTD group showed extensive bilateral atrophy predominantly involving frontal and temporal lobes. Within the FTD group, the severity of apathy correlated with atrophy in the right dorsolateral prefrontal cortex. The severity of disinhibition correlated with atrophy in the right nucleus accumbens, right superior temporal sulcus, and right mediotemporal limbic structures.

CONCLUSIONS

Prefrontal and temporal regions are differentially associated with apathy and disinhibition. Our results support the view that successful execution of complex social behaviors relies on the integration of social knowledge and executive functions, represented in the prefrontal cortex, and reward attribution and emotional processing, represented in mesolimbic structures.

Lexical acquisition in progressive aphasia and frontotemporal dementia

We investigated the characteristics of language difficulty in frontotemporal dementia (FTD) by exposing these patients to a new verb in a naturalistic manner and then assessing acquisition of the grammatical, semantic, and thematic matrix information associated with the new word. We found that FTD patients have difficulty relative to healthy seniors in their acquisition of the new verb, but that progressive nonfluent aphasia (PNFA), semantic dementia (SD), and social/dysexecutive variant (SOC/EXEC) subgroups of FTD demonstrate relatively distinct impairment profiles. Specifically, PNFA patients showed relative difficulty assigning the new verb to its correct grammatical form class, reflecting compromised processing of the associated grammatical information. SD patients were impaired at associating the new word with its pictorial representation, suggesting impaired processing of the new verb's semantic attributes. SOC/EXEC patients showed their greatest difficulty judging violations of the new word's associated thematic roles, implying that limited executive resources underlie in part the difficulty in integrating grammatical and semantic information into a coherent thematic matrix. Similar impairment profiles were seen during a follow-up session one week after the initial evaluation. These deficits in lexical acquisition reflect the breakdown of a language-processing system that consists of highly interactive but partially dissociable grammatical, semantic, and resource-based components, leading to relatively distinct language-processing deficits in each subgroup of patients with FTD.

A model for management of behavioral symptoms in frontotemporal lobar degeneration

Frontotemporal lobar degeneration is a neurologic condition that manifests profound behavioral, personality, and language symptoms. These changes, often unique to each person, may include social misconduct, eating disturbances, apathy, emotional blunting, childlike behavior, habits and rituals, executive dysfunction, and marked difficulty with speech and language. These symptoms occur as the result of cell loss in discrete areas of the brain, the frontal and/or anterior temporal lobes. Little is known about effective management of the behavioral symptoms that result from this disease. The purpose of this paper is to describe a model that could be used in the assessment and potential management of frontotemporal lobar degeneration behavioral symptoms. Suggestions for interventions are given for some of the more common FTD behaviors. The impact of behavioral symptoms on the family caregiver is discussed along with strategies for supportive services and recommendations for future study.

Development of the Executive Personal Finance Scale

There is accumulating evidence that prefrontal systems play an important role in management of personal finances, based on studies using clinical populations, functional neuroimaging, and both subjective and objective neuropsychological measures. This study developed the Executive Personal Finance Scale (EPFS) as a specific self-rating measure of executive aspects of personal money management. The resulting 20-item scale had good reliability and showed four factors: impulse control, organization, planning, and motivational drive. Validity was evidenced by correlations with income, credit card debt, and investments. The EPFS also showed logical correlations with compulsive buying and money attitudes. Second-order factor analysis of the EPFS and other scales revealed two higher-order factors of personal finance: cognitive (e.g., planning, organizing) and emotional (e.g., anxiety, impulse-spending, prestige). The EPFS shows good psychometric properties, is easy to use, and will make a convenient complement to other research methodologies exploring the neural basis of personal finance management.

In search of autobiographical memories: A PET study in the frontal variant of frontotemporal dementia

Patients suffering from frontal variant of frontotemporal dementia (fv-FTD) undergo autobiographical amnesia encompassing all time periods. We previously demonstrated in a group of 20 fv-FTD patients that this impairment involved deficits in executive function and semantic memory for all periods as well as new episodic learning and behavioural changes for the most recent period covering the last 12 months [Matuszewski, V., Piolino, P., de la Sayette, V., Lalevée, C., Pélerin, A., Dupuy, B., et al. (2006). Retrieval mechanisms for autobiographical memories: Insights from the frontal variant of frontotemporal dementia, Neuropsychologia, 44, 2386-2397]. The aim of the present study was to unravel the neural bases of this impairment by mapping in a subgroup of patients correlations between resting-state brain glucose utilization measured by FDG-PET and measures of autobiographical memory (AM) using the TEMPau task which is designed to gauge personal event recollection across five life time periods. Like in our previous report, the group of patients was impaired regardless of time periods compared to healthy subjects providing generic memories instead of event specific sensory-perceptual-affective details, i.e., episodic memories. New data showed that the patients were also impaired in sense of reliving and self-perspective during retrieval. The cognitivo-metabolic correlations between the AM score and resting normalized FDG-Uptake were computed using statistical parametric mapping (SPM2) and controlling for age and dementia severity. They revealed that AM deficits were mainly subserved by the dysfunction of left-sided orbitofrontal and also temporal neocortical areas whatever the period. Additional analysis showed that specific memories were associated with left orbitofrontal areas whereas generic memories were mainly associated with the left temporal pole. This study supports the view that fv-FTD patients undergo a breakdown of generative processes which relies regardless of the remoteness on the left orbitofrontal cortex and temporal neocortex to gain access to AM.

Resisting the power of temptations: the right prefrontal cortex and self-control

Imagine you are overweight and you spot your favorite pastry in the storefront of a bakery. How do you manage to resist this temptation? Or to give other examples, how do you manage to restrain yourself from overspending or succumbing to sexual temptations? The present article summarizes two recent studies stressing the fundamental importance of inhibition in the process of decision making. Based on the results of these studies, we dare to claim that the capacity to resist temptation depends on the activity level of the right prefrontal cortex (PFC).

Behavioral disturbances in the course of frontotemporal dementia

BACKGROUND

Behavioral disturbances are prominent in frontotemporal dementia (FTD), and their occurrence has been the topic of several investigations. Nonetheless, the prevalence and severity of behavioral disturbances of patients with FTD in different degrees of dementia severity have rarely been studied.

OBJECTIVE

The aim of this study was to assess and compare the prevalence and severity of behavioral disturbances in patients with mild FTD and in patients with moderate/severe dementia.

METHODS

We included 21 outpatients with mild FTD [Clinical Dementia Rating (CDR) = 1] and 19 patients with moderate or severe dementia (CDR = 2 or 3) in this study. Behavioral disturbances were assessed using the Neuropsychiatric Inventory (NPI).

RESULTS

We found a statistically significant difference in the total NPI scores between patients with mild FTD and patients with moderate or severe FTD, the latter scoring higher. Apathy was the most prevalent symptom in both patient groups (90.5 and 100%). Except appetite and eating disturbance, which appeared in 77.8% of the patients with moderate/severe dementia, all other symptoms were clearly less common (<50%).

CONCLUSION

The results highlight the variability of behavioral disturbances in mild and moderate/severe stages of FTD.

Funktionelle Hemisphärenasymmetrie der Selbstkontrolle?

Zusammenfassung: Durch die Fähigkeit zur Selbstkontrolle gelingt es uns, diejenigen Aktivitäten zu unterdrücken, die einem angestrebten Ziel oder dem aktuellen sozialen Kontext entgegenstehen. Welche neuronalen Prozesse liegen der Selbstkontrolle zugrunde? Ein vertieftes Verständnis der relevanten neuronalen Mechanismen kann insofern von therapeutischer Relevanz sein, als Störungen der Selbstkontrolle ein zentrales Merkmal vieler neurologischer und psychiatrischer Erkrankungen darstellen. Der vorliegende Artikel fasst vorwiegend eigene experimentelle Arbeiten zusammen, deren Resultate die - aufgrund von Beobachtungen an Patienten mit Schädigungen im Frontalhirn formulierte - Annahme einer lateralisierten Organisation der Selbstkontrolle stützen. Basierend auf diesen Berichten formulieren wir die Schlussfolgerung, dass die Fähigkeit zur Selbstkontrolle, die für ein adäquates Entscheidungsverhalten von fundamentaler Bedeutung ist, über rechtsseitige Regelsysteme organisiert ist und durch kortikale Stimulation vorübergehend moduliert werden kann.

Relationship between antisocial behavior and regional cerebral blood flow in frontotemporal dementia

OBJECTIVE

To examine the relationship between antisocial behaviors and reduction of regional cerebral blood flow (rCBF) in patients with frontotemporal dementia (FTD).

METHODS

Brain perfusion single photon emission computed tomography (SPECT) was performed in 22 patients with FTD and 76 age-matched healthy volunteers. The statistical analysis was conducted using the SPM99 software. The antisocial behavioral symptoms were assessed independently by three geriatric psychiatrists, who had not been given the information of the SPECT images.

RESULTS

Compared with normal controls, FTD patients showed significant reduction of rCBF in the widespread frontal cortical areas. The correlation analysis showed that antisocial behavioral symptoms are associated with reduction of rCBF in the orbitofrontal cortex.

CONCLUSION

The functional decline of orbitofrontal cortex is related to antisocial behavioral symptoms in patients with FTD.

Neuropsychological differences between frontotemporal dementia and Alzheimer's disease: a review

This paper surveys the similarities and differences between frontotemporal dementia (FTD) and Alzheimer's disease (AD). The review covers findings primarily from neuropsychological studies on memory, language, attention/executive function, and visuospatial abilities. However, neuropsychiatric and neuroimaging data are also briefly discussed. Distinguishing features of both FTD and AD are described in order to present a comprehensive clinical picture of these dementing diseases, which is essential for the process of differential diagnosis. The cause of specific cognitive deficits is also considered. Our comprehensive review of the empirical literature reveals that AD is characterized by early memory loss and visuospatial problems, while among the main features of FTD are behavioral abnormalities and executive dysfunctions.

Functional neuroimaging and presenting psychiatric features in frontotemporal dementia

BACKGROUND

Frontotemporal dementia (FTD) is a behavioural syndrome caused by degeneration of the frontal and anterior temporal lobes. Behavioural disturbances include psychiatric features. Whether patients with FTD present with psychiatric features varies with the initial neuroanatomical variability of FTD.

OBJECTIVE

To identify presenting psychiatric changes not part of diagnostic criteria of FTD and contrast them with the degree of hemispheric asymmetry and frontal and temporal hypoperfusion on single photon emission computed tomography (SPECT) imaging.

METHODS

74 patients who met consensus criteria for FTD were evaluated at a two year follow up. All had brain SPECT on initial presentation. Results of an FTD psychiatric checklist were contrasted with ratings of regional hypoperfusion.

RESULTS

The regions of predominant hypoperfusion did not correlate with differences on FTD demographic variables but were associated with presenting psychiatric features. Dysthymia and anxiety were associated with right temporal hypoperfusion. "Moria" or frivolous behaviour also occurred with temporal lobe changes, especially on the right. The only significant frontal lobe feature was the presence of a peculiar physical bearing in association with right frontal hypoperfusion.

CONCLUSIONS

Patients with FTD may present with psychiatric changes distinct from the behavioural diagnostic criteria for this disorder. Early temporal involvement is associated with frivolous behaviour and right temporal involvement is associated with emotional disturbances. In contrast, those with right frontal disease may present with alterations in non-verbal behaviour.

How does the brain support script comprehension? A study of executive processes and semantic knowledge in dementia

The neuropsychological substrate of scripts, routines which guide much of human behavior, is unclear. We propose a model of script comprehension characterized by the interaction of semantic knowledge for script content, and executive resources that organize this knowledge into goal directed behavior. We examined these neuropsychological components by asking participants with Alzheimer's disease (AD) and frontotemporal dementia (behavioral disorder/dysexecutive syndrome (BDD) and semantic dementia (SD) subtypes), to judge the coherence of four-phrase scripts. The BDD group detected significantly fewer sequencing errors than semantic errors; the AD and SD groups detected these errors with equal frequency. Independent semantic measures predicted both semantic and sequencing script errors, while executive measures predicted sequencing errors only. Findings support a multi-component model of script comprehension.

Retrieval mechanisms for autobiographical memories: Insights from the frontal variant of frontotemporal dementia

Very few studies have investigated autobiographical memory in the frontal variant of frontotemporal dementia (fv-FTD). The aim of this study was therefore to unravel the mechanisms of autobiographical memory disruption in general and in the anterograde and retrograde components of amnesia in particular, in patients suffering from fv-FTD. An autobiographical memory task assessing overall (AM) and strictly episodic memories (EM) from five lifetime periods covering the entire lifespan revealed the absence of a temporal gradient for both scores, suggesting the existence of a retrieval deficit. An analysis of the correlation between these two scores and a general cognitive assessment of executive function, working, episodic (i.e. new learning ability) and semantic memory, and behavioural changes highlighted the considerable involvement of executive function, semantic memory and, to a lesser degree, episodic memory and behavioural changes. Moreover, step-wise regression analyses performed on the EM score revealed that the executive function was a better predictor of the retrograde component than of the anterograde component, which was linked principally to new episodic learning ability. All these results confirm the impact of executive dysfunction on autobiographical deficits in fv-FTD, and suggest that the mechanisms at the root of autobiographical memory disruption may also involve difficulties in new episodic learning and semantic storage, though this may be due to the fact that we studied an advanced form of fv-FTD.

Decomposition of metabolic brain clusters in the frontal variant of frontotemporal dementia

Previous studies that measured brain activity in frontotemporal dementia (FTD) used univariate analyses, examining each region of interest separately. We explored in a multicenter European research program the principal brain clusters characterized by a common variability in cerebral metabolism in FTD. Seventy patients with frontal variant (fv) FTD were selected according to international clinical recommendations; principal component analysis (PCA) was performed on FDG-PET metabolic images, looking for covariance clusters in this large population. A first metabolic cluster included most of the lateral and medial prefrontal cortex, bilaterally; PC1 scores correlated with performances on memory and executive neuropsychological tasks. Moreover, FDG-PET images in fv-FTD were further characterized by a metabolic covariance in two clusters comprising the subcallosal medial frontal region, the temporal pole, medial temporal structures and the striatum, separately in the left and in the right hemisphere. The study provides original data-driven arguments for metabolic involvement of separate brain clusters in the rostral limbic system, corresponding to pathological poles differentially affected in each FTD patient.

Behavioural changes and psychological symptoms in dementia disorders

The traditional view of dementia is that the features most important to accurate diagnosis and management are cognitive decline and functional disability. Behavioural and psychological symptoms have generally been thought to be of secondary importance, but new evidence suggests that these are important determinants of patients' distress, carer burden, and outcome in dementia; they can also be valuable diagnostic pointers to the underlying pathological cause and disease diagnosis. Better methods to detect and measure the severity of behavioural and psychological symptoms are needed and these could be used in well-designed intervention trials. Although pharmacological management is a commonly used option, it is often limited in its effects and can be associated with a substantial risk of side-effects. Progress in understanding the pathophysiological mechanisms underpinning behavioural and psychological symptoms in dementia will assist in developing more effective treatment approaches.

Acquired sociopathy and frontotemporal dementia

BACKGROUND

It is not understood why some patients with frontotemporal dementia (FTD) manifest sociopathic behavior.

OBJECTIVE

To examine the prevalence and characteristics of sociopathic behavior in FTD patients as compared to those with Alzheimer's disease (AD).

METHODS AND PARTICIPANTS

We surveyed a group of FTD patients and a group of AD patients for sociopathic behavior, evaluated the characteristics surrounding their acts, and compared the groups on neuropsychological tests and functional neuroimaging. Twenty-eight outpatients with FTD (15 men, 13 women; 61.9+/-7.1 years; Mini-Mental State Examination score 23.6+/-8.1) were compared with 28 patients with clinically probable AD (13 men, 15 women; 66.1+/-9.2 years; Mini-Mental State Examination score 21.3 +/- 5.3). Main outcome measures included: (a) the prevalence of sociopathic acts; (b) a structured interview; (c) neuropsychological tests including the Frontal Assessment Battery, and (d) clinically obtained positron emission tomography or single photon emission tomography scans.

RESULTS

Sixteen (57%) of the FTD patients had sociopathic behavior compared to two (7%) of the AD patients (chi(2)=13.84, p<0.001). Sociopathic acts among FTD patients included unsolicited sexual acts, traffic violations, physical assaults, and other unacceptable behaviors. On interview, the FTD patients with sociopathic acts were aware of their behavior and knew that it was wrong but could not prevent themselves from acting impulsively. They claimed subsequent remorse, but they did not act on it or show concern for the consequences. Among FTD patients with sociopathy, neuropsychological assessment showed impaired motor inhibition, and functional neuroimaging showed right frontotemporal involvement.

CONCLUSION

The results suggest that sociopathy in FTD results from a combination of diminished emotional concern for the consequences of their acts and disinhibition consequent to right frontotemporal dysfunction. In many jurisdictions, FTD patients with sociopathy would not pass legal criteria for 'not guilty by reason of insanity'.

Clinical Features of Frontotemporal Dementia

What was once called Pick's disease has three major anatomic variants. With all three, frontotemporal brain is selectively injured whereas posterior cortical regions are spared. These three clinical patterns include a bifrontal, slightly asymmetric subtype with more involvement of the right frontotemporal region called frontotemporal dementia or the frontal variant of FTD (fvFTD), a temporal-predominant subtype called the temporal variant of FTD or semantic dementia (SD), and a left frontal-predominant subtype called progressive nonfluent aphasia (PNFA). The three anatomic groups help to classify distinctive clinical syndromes with unique features. Careful study of these subtypes of frontotemporal dementia, using combinations of new quantitative neuroimaging, behavioral and physiological measures are yielding important information about the functioning of the brain's frontal and temporal regions. As we come to better understand the biologic basis for the three FTD clinical syndromes, new classification schemas may emerge, but our current clinical criteria serve as a strong guide to the diagnosis and separation of FTD from Alzheimer disease and other dementias.

Neuroanatomical correlates of behavioural disorders in dementia

Neurodegenerative diseases are associated with profound changes in social and emotional function. The emergence of increasingly sophisticated methods for measuring brain volume has facilitated correlation of local changes in tissue content with cognitive and behavioural changes in neurodegenerative disease. The current study examined neuroanatomical correlates of behavioural abnormalities, as measured by the Neuropsychiatric Inventory, in 148 patients with dementia using voxel-based morphometry. Of 12 behaviours examined, 4 correlated with tissue loss: apathy, disinhibition, eating disorders and aberrant motor behaviour. Increasing severity across these four behaviours was associated with tissue loss in the ventral portion of the right anterior cingulate cortex (vACC) and adjacent ventromedial superior frontal gyrus (vmSFG), the right ventromedial prefrontal cortex (VMPC) more posteriorly, the right lateral middle frontal gyrus, the right caudate head, the right orbitofrontal cortex and the right anterior insula. In addition, apathy was independently associated with tissue loss in the right vmSFG, disinhibition with tissue loss in the right subgenual cingulate gyrus in the VMPC, and aberrant motor behaviour with tissue loss in the right dorsal ACC and left premotor cortex. These data strongly support the involvement of the right hemisphere in mediating social and emotional behaviour and highlight the importance of distinct regions on the medial wall of the right frontal lobe in regulating different behaviours. Furthermore, the findings underscore the utility of studying patients with dementia for understanding the neuroanatomical basis of social and emotional functions.

Neuroanatomical correlates of impaired recognition of emotion in dementia

Neurodegenerative diseases frequently affect brain regions important for emotional processing, offering a valuable opportunity to study the effects of brain injury on emotion. The current study examined the neuroanatomical correlates of impaired recognition of emotions in patients with neurodegenerative disease. Performance on recognition of facial expressions, as measured by the Florida Affect Battery, was correlated with regional changes in gray matter tissue content in 50 patients with neurodegenerative disease using voxel-based morphometry. Recognition accuracy in the group was poor for negative emotions (fear, anger and sadness) and good for happiness, consistent with previous studies. For negative emotions, a region in the right lateral inferior temporal gyrus (Brodman's area (BA) 20) extending into the right middle temporal gyrus (BA 21) was correlated with accuracy. This effect appeared to be strongest for sadness, which was also independently correlated with atrophy in the superior temporal gyrus. These data suggest that regions in the right lateral and inferolateral temporal lobe are important for visual processing of negative emotions from faces and that functioning of this right temporal network is most critical for recognition of sad faces.

Neural correlates of semantic and behavioural deficits in frontotemporal dementia

Patients with frontotemporal dementia (FTD) can present with the clinical syndrome of semantic dementia due to a progressive loss of semantic knowledge or a neuropsychiatric syndrome characterised by aberrant social behaviours although frequently both co-exist. It has been assumed that the former is underpinned by damage to the temporal lobes and the latter, predominantly, by damage to the frontal lobes. Using the technique of voxel-based morphometry, we studied a group of FTD cases (n = 18) with a range of cognitive and neuropsychiatric features to correlate loss of semantic knowledge (as measured by the sum of two semantic tests) and aberrant behaviour (as measured by the neuropsychiatric inventory, NPI) with regional loss of grey matter volume. Semantic breakdown correlated with extensive loss of grey matter volume throughout the left anterior temporal lobe and less significantly with right temporal pole and subcallosal gyrus. Aberrant behaviour correlated with loss of grey matter volume in the dorso-mesial frontal lobe--paracingulate region, Brodmann areas 6/8/9--more so on the right. The frontal paracingulate correlation suggests that damage to this region may significantly contribute to the genesis of the behavioural syndrome seen in FTD.

Behavioral disorders in the frontal and temporal variants of frontotemporal dementia

OBJECTIVE

To compare the behavioral features and to investigate the neuroanatomic correlates of behavioral dysfunction in anatomically defined temporal and frontal variants of frontotemporal dementia (tvFTD and fvFTD).

METHODS

Volumetric measurements of the frontal, anterior temporal, ventromedial frontal cortical (VMFC), and amygdala regions were made in 51 patients with FTD and 20 normal control subjects, as well as 22 patients with Alzheimer disease (AD) who were used as dementia controls. FTD patients were classified as fvFTD or tvFTD based on the relative degree of frontal and anterior temporal volume loss compared with controls. Behavioral symptoms, cerebral volumes, and the relationship between them were examined across groups.

RESULTS

Both variants of FTD showed significant increases in rates of elation, disinhibition, and aberrant motor behavior compared with AD. The fvFTD group also showed more anxiety, apathy, and eating disorders, and tvFTD showed a higher prevalence of sleep disturbances than AD. The only behaviors that differed significantly between fvFTD and tvFTD were apathy, greater in fvFTD, and sleep disorders, more frequent in tvFTD. FvFTD was associated with greater frontal atrophy and tvFTD was associated with more temporal and amygdala atrophy compared with AD, but both groups showed significant atrophy in the VMFC compared with AD, which was not associated with VMFC atrophy. In FTD, the presence of many of the behavioral disorders was associated with decreased volume in right-hemispheric regions.

CONCLUSION

FvFTD and tvFTD show many similarities in behavior, which appear to be associated with damage to right frontal and temporal structures.

Non-Alzheimer's disease dementias: anatomic, clinical, and molecular correlates

OBJECTIVE

To review the clinical and molecular features of non-Alzheimer's disease (non-AD) dementias, focusing on disorders associated with tau pathology (that is, frontotemporal lobar degeneration [FTLD], corticobasal ganglionic degeneration [CBD], and progressive supranuclear palsy [PSP]) or on disorders with synuclein pathology (that is, dementia with Lewy bodies [DLB] and multisystem atrophy [MSA]). We also discuss the pharmacologic treatment of these disorders.

METHODS

We report a selective review of the literature on FTLD, CBD, PSP, DLB, and MSA.

RESULTS

The non-AD dementias can present with a wide variety of cognitive and behavioural symptoms. Through common clinical features and shared molecular etiologies, neurodegenerative disorders previously thought to be distinct are now classified into tauopathies and synucleinopathies.

CONCLUSIONS

The unique cognitive and behavioural manifestations of the non-AD dementias can be mistaken for psychiatric disorders. Improved detection of tauopathies and synucleinopathies and their differentiation from AD is possible.

Neuropsychiatric symptoms in the dementias

PURPOSE OF REVIEW

Neuropsychiatric, or non-cognitive symptoms are increasingly recognized as manifestations of dementias.

RECENT FINDINGS

In Alzheimer's disease, recent advances have included the identification of behavioral profiles, differentiation of apathy and depression, characterization of risk factors for psychosis and its links to agitation and aggression, and an analysis of depressive symptoms in the absence of major depression. Functional neuroimaging data mainly supported the role of the anterior cingulate in apathy. The orbitofrontal and anterior cingulate tangle burden were associated with agitation, and increased orbitofrontal and mid-temporal muscarinic M2 receptors with psychosis and hallucinations. Selected genetic polymorphisms of dopamine and serotonin receptors or transporters were linked with aggression, hallucinations or psychosis. When compared with other dementias, individuals with frontotemporal dementia disclosed, as expected, different behaviors and particularly aberrant social behavior. The frequency of delusions and visual hallucinations was increased in Parkinson's disease, Parkinson's disease with dementia, and dementia with Lewy bodies, suggesting common mechanisms such as Lewy body pathology and cholinergic deficiency. The latter was supported by an improvement of these symptoms by cholinesterase inhibitors.

SUMMARY

Future research directions include both clinical and basic neuroscience investigations. The detection of early neuropsychiatric symptoms might be a marker for dementia, and the possible existence of a mild neuropsychiatric impairment syndrome should be explored. More longitudinal studies with pathological confirmation will facilitate correlations with neuropsychiatric symptoms. Functional neuroimaging and behavioral neurogenetics will permit in-vivo correlations and consequently help patient management and care.