Felicity V. C. Leslie

Distinguishing Subtypes in Primary Progressive Aphasia: Application of the Sydney Language Battery

Background/Aims: Primary progressive aphasia (PPA) comprises three main subtypes, varying in clinical features, patterns of brain atrophy, and underlying pathology. Differentiation of these variants is important for treatment and planning; however, simple, effective cognitive tests to aid diagnosis are lacking. This study introduces a new language battery - the SYDBAT (Sydney Language Battery) - to assist clinicians. Methods: Fifty-seven PPA patients and 54 age- and education-matched healthy controls were compared on naming, repetition, word comprehension, and semantic association subtests. Results: Significant group differences were found for all tasks, reflecting different language profiles for each group. Using discriminative function analysis, 80% of PPA cases were correctly classified from three SYDBAT scores, from which a simple diagnostic algorithm was defined. Conclusion: The SYDBAT is a fast and simple tool which provides a valuable adjunct to clinicians diagnosing PPA.

The impact of dementia severity on caregiver burden in frontotemporal dementia and Alzheimer disease.

Caregiver burden is greater in frontotemporal dementia (FTD) than in Alzheimer disease (AD). However, little is known of the impact of the 3 main clinical variants of FTD— behavioral-variant frontotemporal dementia (bvFTD), semantic dementia (SemDem), and progressive nonfluent aphasia (PNFA)—or the role of disease severity in caregiver burden. The Zarit Burden Inventory was used to measure caregiver burden of bvFTD (n=17), SemDem (n=20), PNFA (n=20), and AD (n=19) patients. Symptom duration, caregiver age, and relationship type were matched across groups. Moreover, a number of caregiver (mood, social network) and patient variables (functional disability, behavioral changes, relationship with caregiver, and dementia stage) were addressed to investigate their impact on caregiver burden. Caregivers of bvFTD patients reported the highest burden, whereas SemDem and PNFA caregivers reported burden similar to AD. A regression analysis revealed that caregiver burden in FTD, regardless of subtype, was explained by a model combining disease staging, relationship changes, and caregiver depression. Burden increased with disease severity in FTD. This study is the first to show that caregivers of SemDem, PNFA, and AD patients show similar burden, while confirming that bvFTD caregivers show higher burden than AD caregivers. More importantly, this study demonstrates that burden worsens with disease progression in FTD.

The Mini-Addenbrooke's Cognitive Examination: A New Assessment Tool for Dementia

Background/Aims: We developed and validated the Mini-Addenbrookes Cognitive Examination (M-ACE) in dementia patients. Comparisons were also made with the Mini Mental State Examination (MMSE). Method: The M-ACE was developed using Mokken scaling analysis in 117 dementia patients [behavioural variant frontotemporal dementia (bvFTD), n = 25; primary progressive aphasia (PPA), n = 49; Alzheimers disease (AD), n = 34; corticobasal syndrome (CBS), n = 9] and validated in an independent sample of 164 dementia patients (bvFTD, n = 23; PPA, n = 82; AD, n = 38; CBS, n = 21) and 78 controls, who also completed the MMSE. Results: The M-ACE consists of 5 items with a maximum score of 30. Two cut-offs were identified: (1) ≤25/30 has both high sensitivity and specificity, and (2) ≤21/30 is almost certainly a score to have come from a dementia patient regardless of the clinical setting. The M-ACE is more sensitive than the MMSE and is less likely to have ceiling effects. Conclusion: The M-ACE is a brief and sensitive cognitive screening tool for dementia. Two cut-offs (25 or 21) are recommended.

Grief and joy: emotion word comprehension in the dementias.

OBJECTIVE Word comprehension deficits in neurodegenerative conditions are most striking in the syndrome of semantic dementia. Tests of word comprehension typically examine concrete and abstract nonemotion words. Whether or not understanding of words describing emotion concepts (e.g., insulted, fascinated) is also impaired in the dementias has not been systematically investigated. METHOD Patients with semantic dementia (SD; n = 8), behavioral-variant frontotemporal dementia (bvFTD; n = 8), Alzheimers disease (AD; n = 12), as well as healthy controls (n = 15) completed newly designed emotion word comprehension tasks. Participants also undertook the Graded Synonyms Test, an abstract and concrete nonemotion word comprehension measure. RESULTS Degradation of knowledge about negative and positive emotion words was most impaired in SD. Correlation analyses in the SD group also showed that knowledge of emotion words correlated with the understanding of abstract nonemotion words. The bvFTD group was impaired only when making associations for emotion words. The AD cohort did not differ from controls on any measures of word comprehension. CONCLUSIONS Impairment in word knowledge is greatest in the syndrome of SD, compared with bvFTD and AD, and includes concrete words, abstract words as well as emotion words. Importantly, word comprehension deficits affect positive and negative emotions.

Semantic deficits in amyotrophic lateral sclerosis.

Abstract Our objective was to investigate, and establish neuroanatomical correlates of, semantic deficits in amyotrophic lateral sclerosis (ALS) and amyotrophic lateral sclerosis-frontotemporal dementia (ALS-FTD), compared to semantic dementia (SD) and controls. Semantic deficits were evaluated using a naming and semantic knowledge composite score, comprising verbal and non-verbal neuropsychological measures of single-word processing (confrontational naming, comprehension, and semantic association) from the Sydney Language Battery (SYDBAT) and Addenbrookes Cognitive Examination – Revised (ACE-R). Voxel based morphometry (VBM) analysis was conducted using the region of interest approach. In total, 84 participants were recruited from a multidisciplinary research clinic in Sydney. Participants included 17 patients with ALS, 19 with ALS-FTD, 22 with SD and 26 age- and education-matched healthy controls. Significant semantic deficits were observed in ALS and ALS-FTD compared to controls. The severity of semantic deficits varied across the clinical phenotypes: ALS patients were less impaired than ALS-FTD patients, who in turn were not as impaired as SD patients. Anterior temporal lobe atrophy significantly correlated with semantic deficits. In conclusion, semantic impairment is a feature of ALS and ALS-FTD, and reflects the severity of temporal lobe pathology.

Motor function and behaviour across the ALS-FTD spectrum

Behavioural/functional disturbances, characteristic of frontotemporal dementia (FTD), are also a feature of amyotrophic lateral sclerosis (ALS) and patients with combined ALS and FTD (FTD‐ALS).

Cognitive and Behavioral Symptoms in ALSFTD Detection, Differentiation, and Progression

Brief screening tools that detect and differentiate patients with amyotrophic lateral sclerosis and frontotemporal dementia (ALSFTD) from those more subtle cognitive or behavioral symptoms (ALS plus) and motor symptoms only (ALS pure) is pertinent in a clinical setting. The utility of 2 validated and data-driven tests (Mini-Addenbrooke’s Cognitive Examination [M-ACE] and Motor Neuron Disease Behavioral Scale [MiND-B]) was investigated in 70 ALS patients (24 ALSFTD, 19 ALS plus, and 27 ALS pure). More than 90% of patients with ALSFTD scored at or below the cutoff on the M-ACE, whereas this was seen in only about 20% of ALS patients without dementia. The MiND-B differentiated between ALS pure and ALS plus diagnostic categories. Rasch modeling of M-ACE and MiND-B items revealed early cognitive (fluency, memory recall) and behavioral (apathy) symptoms in ALSFTD. The combined use of the M-ACE and MiND-B detects patients with ALSFTD, differentiates along the ALS continuum, and offers insight into the progression of nonmotor symptomatology in ALSFTD.

Probabilistic association learning in frontotemporal dementia and schizophrenia

INTRODUCTION Recent neuropsychological studies show substantial cognitive deficits in patients with frontotemporal dementia (FTD). Schizophrenia (SC) overlaps in terms of neurobehavioural symptoms with FTD. Probabilistic association learning, which is thought to assay fronto-striatal function, is well documented to elicit impairment in SC and has not been investigated in FTD to date; this study compared FTD, SC and a healthy comparison group on probabilistic association learning to determine the extent to which FTD patients were similar in performance to SC patients. METHODS Twenty FTD patients, 24 SC patients and 26 healthy controls were assessed using the probabilistic association learning weather prediction test. FTD patients were also divided into behavioural and language variants for comparison to the healthy group. RESULTS FTD patients were impaired during probabilistic association learning in comparison to healthy controls. There was no difference in performance between the FTD and SC groups. FTD behavioural variants performed significantly worse than the healthy comparison group, while FTD language variants did not differ from the healthy comparison group. CONCLUSIONS This study provides the first evidence for impaired probabilistic association learning in FTD which is of an equivalent degree to that seen in SC. These results support recent structural neuroimaging studies showing fronto-striatal abnormalities in FTD and suggest that fronto-striatal dysfunction may contribute to cognitive deficits in a significant proportion of people with FTD.

FRONTIER Executive Screen: a brief executive battery to differentiate frontotemporal dementia and Alzheimer's disease

Background and objective Executive dysfunctions are a key clinical feature of behavioural-variant frontotemporal dementia (bvFTD). Such deficits are also found in Alzheimers disease (AD), making the differentiation between these two diseases difficult at times, particularly in the absence of extensive cognitive assessments. To address this issue, we developed the FRONTIER Executive Screen (FES), which combines three abbreviated measures of verbal fluency, inhibitory control and working memory. Methods We administered the FES to 28 patients with dementia (14 bvFTD, 14 AD) matched for disease severity and 33 age-matched and education-matched healthy controls. We also administered traditional tests of executive function to establish the concurrent validity of the FES. Results Both patient groups obtained lower FES scores (total and subscores) compared to controls. Correct classification into patient or control groups was reached in over 90% of study participants based on the FES total score. Only two patients with bvFTD obtained FES scores within 2 SDs of the control group. Receiver operating characteristic analyses on the patient groups showed that a cut-off FES total score of 7/15 achieved 71% sensitivity and 73% specificity for a diagnosis of bvFTD. In addition, the FES showed high correlations with traditional measures of executive function. Conclusions The FES is a brief (5–10 min) bedside screening measure which is simple to administer and score, and demonstrates good discriminative validity to differentiate bvFTD from AD. It is a useful addendum to general cognitive screening measures and can help with the differential diagnosis of dementia.

Intrafamilial Phenotypic Variability in the C9orf72 Gene Expansion: 2 Case Studies

The C9orf72 genetic mutation is the most common cause of familial frontotemporal dementia (FTD) and motor neuron disease (MND). Previous family studies suggest that while some common clinical features may distinguish gene carriers from sporadic patients, the clinical features, age of onset and disease progression vary considerably in affected patients. Whilst disease presentations may vary across families, age at disease onset appears to be relatively uniform within each family. Here, we report two individuals with a C9orf72 repeat expansion from two generations of the same family with markedly different age at disease onset, clinical presentation and disease progression: one who developed motor neuron and behavioural symptoms in their mid 40s and died 3 years later with confirmed TDP-43 pathology and MND; and a second who developed cognitive and mild behavioural symptoms in their mid 70s and 8 years later remains alive with only slow deterioration. This report highlights the phenotypic variability, including age of onset, within a family with the C9orf72 repeat expansion.