Emma Devenney

Frontotemporal Dementia Associated With the C9ORF72 Mutation: A Unique Clinical Profile

IMPORTANCE While advances have been made in characterizing the C9ORF72 clinical phenotype, the hallmark features that discriminate between carriers and noncarriers remain unclear. OBJECTIVES To determine the frequency of the C9ORF72 mutation in a frontotemporal dementia (FTD) cohort and to define the clinical, neuropsychological, behavioral, and imaging features of C9ORF72 mutation carriers in comparison with noncarriers in a well-defined behavioral-variant (bv)-FTD cohort. DESIGN, SETTING, AND PARTICIPANTS A prospective cohort study of patients assessed during a 5-year period from January 1, 2008, to December 31, 2012, at an FTD specialist referral center (FRONTIER). A total of 114 consecutive patients with FTD, FTD-amyotrophic lateral sclerosis (ALS), and corticobasal syndrome were assessed at FRONTIER. Patients with bvFTD who carried the C9ORF72 mutation (n = 10) were compared with noncarriers (n = 19) and a healthy control group (n = 35). These were matched for age, sex, and education history. Blood sampling for gene analysis was performed after informed consent was obtained. MAIN OUTCOMES AND MEASURES Clinical, behavioral, cognitive, and neuropsychological deficits, cortical atrophy on a magnetic resonance imaging visual rating scale, and family history as quantified by the Goldman Scale. RESULTS In a cohort of 114 FTD cases, 14 patients expressed the C9ORF72 mutation, representing a frequency rate of 34% in bvFTD and 17% in FTD-ALS. Family histories of ALS (P = .001) and psychiatric disorders (P = .02) were significantly more common in mutation carriers. The C9ORF72 carriers were also more likely to experience psychotic symptoms (P = .03). The degree of brain atrophy was significantly less in the C9ORF72 cohort, and in many the progression was slow. Presenting features of C9ORF72 carriers were compared against International Consensus Diagnostic Criteria for bvFTD, and most cases failed to satisfy criteria for probable bvFTD. CONCLUSIONS AND RELEVANCE The C9ORF72 mutation appears to be a common cause of bvFTD. Many of the C9ORF72 carriers have a family history of ALS or psychiatric illness. Psychotic features emerged as the most discriminating clinical feature between mutation carriers and noncarriers. Progression is often slow and brain atrophy is less pronounced than in nonmutation cases of bvFTD. These findings have clinical relevance for both diagnosis and selection of patients for genetic testing.

Neuropsychiatric changes precede classic motor symptoms in ALS and do not affect survival

Objectives: To investigate patient susceptibility to neuropsychiatric symptoms in the context of progression of more classic motor symptoms in amyotrophic lateral sclerosis (ALS) and to examine the impact of neuropsychiatric symptoms on survival. Methods: The study cohort consisted of 219 patients with ALS (limb onset = 159; bulbar onset = 60), with neuropsychiatric symptoms measured using the Motor Neuron Disease Behavioural Scale and more classic ALS symptoms assessed by the Amyotrophic Lateral Sclerosis Functional Rating Scale–Revised. For detection of symptom susceptibility (neuropsychiatric vs classic motor), a Rasch analysis was applied (n = 219). Cox proportional hazard regression models were used for the survival analysis (n = 115 patients), which incorporated neuropsychiatric and classic motor symptoms. Results: Rasch analysis demonstrated that neuropsychiatric symptoms appeared earlier than classic motor features of ALS. However, differences in neuropsychiatric scores did not affect survival: patients with abnormalities in neuropsychiatric domains did not exhibit a different rate of survival than those without (χ2, 3.447, p = 0.328, −2 log-likelihood 377.341). Conclusions: Neuropsychiatric symptoms appear before classic motor features in ALS, which corroborates the notion that ALS and frontotemporal dementia lie on a disease continuum. The early detection of neuropsychiatric symptoms will be critical to inform clinical decisions and alleviate carer burden. Importantly, subtle neuropsychiatric symptoms alone do not affect survival in ALS, which in turn confirms their pervasive nature in ALS.

Tracking the progression of social cognition in neurodegenerative disorders

Background and purpose Behavioural-variant frontotemporal dementia (bvFTD) and Alzheimers disease (AD) patients experience behavioural and emotion recognition alterations, yet understanding of how socioemotional processing is affected with disease progression is minimal. Additionally, evidence suggests that bvFTD patients with limited brain atrophy on neuroimaging at presentation (bvFTD-la) have a more benign course than those with marked atrophy (bvFTD-ma). Longitudinal investigation of these patients, however, is lacking. Methods We investigated general cognition, emotion recognition and sarcasm detection in 20 bvFTD (8 with limited brain atrophy) and 17 AD patients longitudinally and used mixed models analyses to determine the level and rates of decline across groups over time. Results At baseline, all patient groups performed worse than controls on general cognition and emotion recognition measures. The bvFTD-ma group showed significant impairment on the sarcasm detection task compared with controls. Longitudinally, an overall effect of time was present for general cognition (p<0.001); however, the rate of decline did not differ across groups. Trends for interactions between time and diagnosis were observed for both emotion recognition tasks (p=0.055; p=0.062), with the bvFTD-ma group declining more rapidly than AD or bvFTD-la groups. On the sarcasm detection task, the bvFTD-ma and AD patients declined, whereas bvFTD-la patients remained stable over time (p=0.002). Conclusions Tasks of sarcasm detection represent a clinically useful tool to differentiate between bvFTD and AD at baseline. Furthermore, tasks of socioemotional functioning can track progression within bvFTD and identify bvFTD patients more likely to show a faster rate of decline.

On the right side? A longitudinal study of left- versus right-lateralized semantic dementia

The typical presentation of semantic dementia is associated with marked, left predominant anterior temporal lobe atrophy and with changes in language. About 30% of individuals, however, present with predominant right anterior temporal lobe atrophy, usually accompanied by behavioural changes and prosopagnosia. Here, we aimed to establish whether these initially distinct clinical presentations evolve into a similar syndrome at the neural and behavioural level. Thirty-one patients who presented with predominant anterior temporal lobe atrophy were included. Based on imaging, patients were categorized as either predominant left (n = 22) or right (n = 9) semantic dementia. Thirty-three Alzheimers disease patients and 25 healthy controls were included for comparison. Participants completed the Addenbrookes Cognitive Examination, a Face and Emotion Processing Battery and the Cambridge Behavioural Inventory, and underwent magnetic resonance imaging annually. Longitudinal neuroimaging analyses showed greater right temporal pole atrophy in left semantic dementia than Alzheimers disease, whereas right semantic dementia showed greater orbitofrontal and left temporal lobe atrophy than Alzheimers disease. Importantly, direct comparisons between semantic dementia groups revealed that over time, left semantic dementia showed progressive thinning in the right temporal pole, whereas right semantic dementia showed thinning in the orbitofrontal cortex and anterior cingulate. Behaviourally, longitudinal analyses revealed that general cognition declined in all patients. In contrast, patients with left and right semantic dementia showed greater emotion recognition decline than Alzheimers disease. In addition, left semantic dementia showed greater motivation loss than Alzheimers disease. Correlational analyses revealed that emotion recognition was associated with right temporal pole, right medial orbitofrontal and right fusiform integrity, while changes in motivation were associated with right temporal pole cortical thinning. While left and right semantic dementia show distinct profiles at presentation, both phenotypes develop deficits in emotion recognition and behaviour. These findings highlight the pervasive socio-emotional deficits in frontotemporal dementia, even in patients with an initial language presentation. These changes reflect right anterior temporal and orbitofrontal cortex degeneration, underscoring the role of these regions in social cognition and behaviour.

Cerebellar integrity in the amyotrophic lateral sclerosis-frontotemporal dementia continuum.

Amyotrophic lateral sclerosis (ALS) and behavioural variant frontotemporal dementia (bvFTD) are multisystem neurodegenerative disorders that manifest overlapping cognitive, neuropsychiatric and motor features. The cerebellum has long been known to be crucial for intact motor function although emerging evidence over the past decade has attributed cognitive and neuropsychiatric processes to this structure. The current study set out i) to establish the integrity of cerebellar subregions in the amyotrophic lateral sclerosis-behavioural variant frontotemporal dementia spectrum (ALS-bvFTD) and ii) determine whether specific cerebellar atrophy regions are associated with cognitive, neuropsychiatric and motor symptoms in the patients. Seventy-eight patients diagnosed with ALS, ALS-bvFTD, behavioural variant frontotemporal dementia (bvFTD), most without C9ORF72 gene abnormalities, and healthy controls were investigated. Participants underwent cognitive, neuropsychiatric and functional evaluation as well as structural imaging using voxel-based morphometry (VBM) to examine the grey matter subregions of the cerebellar lobules, vermis and crus. VBM analyses revealed: i) significant grey matter atrophy in the cerebellum across the whole ALS-bvFTD continuum; ii) atrophy predominantly of the superior cerebellum and crus in bvFTD patients, atrophy of the inferior cerebellum and vermis in ALS patients, while ALS-bvFTD patients had both patterns of atrophy. Post-hoc covariance analyses revealed that cognitive and neuropsychiatric symptoms were particularly associated with atrophy of the crus and superior lobule, while motor symptoms were more associated with atrophy of the inferior lobules. Taken together, these findings indicate an important role of the cerebellum in the ALS-bvFTD disease spectrum, with all three clinical phenotypes demonstrating specific patterns of subregional atrophy that associated with different symptomology.

Neuronal network disintegration: common pathways linking neurodegenerative diseases

Neurodegeneration refers to a heterogeneous group of brain disorders that progressively evolve. It has been increasingly appreciated that many neurodegenerative conditions overlap at multiple levels and therefore traditional clinicopathological correlation approaches to better classify a disease have met with limited success. Neuronal network disintegration is fundamental to neurodegeneration, and concepts based around such a concept may better explain the overlap between their clinical and pathological phenotypes. In this Review, promoters of overlap in neurodegeneration incorporating behavioural, cognitive, metabolic, motor, and extrapyramidal presentations will be critically appraised. In addition, evidence that may support the existence of large-scale networks that might be contributing to phenotypic differentiation will be considered across a neurodegenerative spectrum. Disintegration of neuronal networks through different pathological processes, such as prion-like spread, may provide a better paradigm of disease and thereby facilitate the identification of novel therapies for neurodegeneration.

Neural substrates of episodic memory dysfunction in behavioural variant frontotemporal dementia with and without C9ORF72 expansions

The recently discovered hexanucleotide repeat expansion, C9ORF72, has been shown to be among the most common cause of familial behavioural variant frontotemporal dementia (bvFTD) and to be present in a significant minority of apparently sporadic cases. While mounting evidence points to prominent episodic memory dysfunction in bvFTD cases, recent reports have also suggested an amnestic profile in C9ORF72 mutation carriers. No study to date, however, has formally characterised the extent to which episodic memory is impaired in C9ORF72 mutation versus sporadic cases, or the underlying neural substrates of such deficits. We conducted a comparison of C9ORF72 (n = 8) and sporadic (n = 15) bvFTD cases using a battery of verbal and visual episodic memory tasks, and contrasted their performance with that of Alzheimers disease (AD, n = 15) and healthy older control (n = 15) participants. Behaviourally, the two bvFTD groups displayed comparable episodic memory profiles, irrespective of task administered, with prominent impairments evident relative to Controls. Whole-brain voxel-based morphometry analyses revealed distinct neural correlates of episodic memory dysfunction in each patient group. Widespread atrophy in medial prefrontal, medial and lateral temporal cortices correlated robustly with episodic memory dysfunction in sporadic bvFTD cases. In contrast, atrophy in a distributed set of regions in the frontal, temporal, and parietal lobes including the posterior cingulate cortex, was implicated in episodic memory dysfunction in C9ORF72 cases. Our results demonstrate that while episodic memory is disrupted to the same extent irrespective of genetic predisposition in bvFTD, distinct neural changes specific to each patient group are evident. The involvement of medial and lateral parietal regions in episodic memory dysfunction in C9ORF72 cases is of particular significance and represents an avenue of considerable interest for future studies.

Apathy is associated with poor prognosis in Amyotrophic Lateral Sclerosis

Apathy is the most commonly reported behavioural change in amyotrophic lateral sclerosis (ALS). However, the degree to which it affects prognosis and overlaps with depression in this population is unknown. The present study examined the relationship between level of apathy, mortality and survival time and whether apathy was linked to specific symptom clusters of depression.

Motor neuron disease-frontotemporal dementia: a clinical continuum

Overlap between motor neuron disease (MND) and frontotemporal dementia (FTD) occurs at clinical, genetic and pathological levels, and has been recently strengthened through the discovery of the C9orf72 genetic expansion. MND is now considered to be a multisystem disorder in which cognitive involvement may be present and, in some cases, may evolve to frank FTD. Identifying cognitive features in MND can be challenging, while, similarly, motor dysfunction in FTD may be overlooked. As such, the present review aims to decipher the variety of overlapping clinical features across the MND–FTD continuum.

A visual MRI atrophy rating scale for the amyotrophic lateral sclerosis-frontotemporal dementia continuum

Abstract Our objective was to distinguish ALS, ALS-FTD and bvFTD via a novel visual MRI cortical atrophy scale that can be employed in a clinical setting. MRI images of 100 participants (33 ALS, 11 ALS-FTD, 22 bvFTD and 34 controls) were rated in four brain areas: orbitofrontal cortex, anterior temporal pole, anterior cingulate, and motor cortex. Areas were rated on a 5- point Likert scale by two raters blinded to the diagnosis. Results demonstrated that bvFTD patients showed the highest levels of atrophy across all regions, while ALS patients had the lowest atrophy scores. ALS-FTD patients have higher atrophy ratings compared to ALS patients for the motor cortex, anterior cingulate and anterior temporal lobe, with a statistical trend for the orbitofrontal cortex. ALS-FTD patients were not significantly different from bvFTD for any of the brain regions. These findings were confirmed in a post hoc VBM analysis of the same participants. Our study demonstrates that a simple visual MRI rating scale can reliably distinguish ALS, ALS-FTD and bvFTD atrophy patterns in a clinical setting. Motor cortex, anterior cingulate and anterior temporal atrophy emerged as good diagnostic markers for ALS-FTD. Employment of this MRI rating scale can complement clinical diagnostics of patients in the ALS-FTD continuum.