Edinburgh Cognitive and Behavioural ALS Screen (ECAS) in the assessment of early onset dementia
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Date
04/12/2021Author
De Icaza Valenzuela, Mónica Mariana
Metadata
Abstract
Early onset dementia is the gradual cognitive decline that interferes with
independence in everyday activities, when it occurs in people younger than 65
years old (Fadil et al., 2009; American Psychiatric Association, 2013). The
Edinburgh Cognitive and Behavioural ALS Screen (ECAS) was originally
developed to assess cognitive and behavioural changes observed in
amyotrophic lateral sclerosis (ALS) (Abrahams et al. 2014); as between 10-
15% of ALS patients develop frontotemporal dementia, and an additional 35%
develop a milder cognitive impairment of frontotemporal dysfunction
(Goldstein and Abrahams, 2013; Strong et al., 2017). The ECAS includes the
domains of language, fluency, and executive functions for the assessment of
ALS, but it also includes the domains of memory and visuospatial abilities to
differentiate changes from other pathologies, such as Alzheimer’s Disease
(AD) (Abrahams et al. 2014). In addition, the ECAS includes a behavioural
interview. In this thesis I explore whether the ECAS is a sensitive test to the
types of cognitive and behavioural changes in people with early onset
dementia without Amyotrophic Lateral Sclerosis (ALS).
In the first study my objectives were: to investigate the relationship between
the ECAS and the Addenbrooke’s Cognitive Examination (ACE-III); to
investigate the effects of age, education, and IQ on the ECAS, and create
appropriate cut-off scores to determine abnormality. I assessed 80 healthy
participants divided into four groups according to age and education. The
ECAS and the ACE-III had a significant correlation indicating good convergent
validity. IQ, followed by age, were the strongest predictors of the total ECAS
score. While IQ predicted 46% of the ACE-III variance, it only predicted 24%
of the ECAS variance. I created abnormality cut-off scores adjusted for age
and education. This research was published in De Icaza Valenzuela et al.
(2018).
In the second study my aim was to determine the sensitivity of the ECAS to
behavioural variant frontotemporal dementia (bvFTD) without ALS, AD,
primary progressive aphasia (PPA) without ALS, posterior cortical atrophy
(PCA) and mild cognitive impairment (MCI). I also validated the ECAS against
a comprehensive neuropsychological assessment, and compared it with the
ACE-III, for each diagnosis. We additionally performed a qualitative thematic
analysis of the ECAS behavioural interviews to determine the differences in
themes between the diagnoses of bvFTD and AD. The study included 16
people with bvFTD (without ALS), 32 with AD, 12 with MCI, 13 with PPA, 6
with PCA and 48 healthy controls. The ECAS was more sensitive than the
ACE-III to detect bvFTD, AD, MCI and PPA; with equal sensitivity to detect
PCA. The anterior functions (comprising executive, fluency and language
scores) composite score was sensitive to bvFTD; while the posterior
functions (comprising memory and visuospatial scores) composite score
was sensitive to AD. The ECAS was able to detect cognitive impairment as
determined by a comprehensive neuropsychological assessment in most of
the patients. A cut-off of 4 or more behavioural domains affected differentiated
well between bvFTD and AD, while different themes emerged between the
groups in the qualitative analysis of the behavioural interview.
Finally, for the third study my objectives were: to investigate the relationship
between the ECAS and functional severity of dementia; to validate the
behavioural interview of the ECAS with other behavioural screens used to
assess FTD; and to determine whether the ECAS scores changed over time
in bvFTD, AD, MCI, PPA, and PCA. For this purpose, I did a longitudinal study
and analysed the correlations between the ECAS with the Clinical Dementia
Rating Scale (CDR-FTLD), the Frontal Behavioural Inventory (FBI), and the
Frontotemporal Dementia Rating Scale (FRS). I assessed 56 patients on the
first assessment, 29 on the second assessment and 13 on the third
assessment. The ECAS total score had good convergent validity with the
CDR-FTLD severity classification, while the ECAS behavioural screen had
convergent validity with the FBI, FRS and CDR-FTLD. I created an impairment
cut-off score of 96 to differentiate the groups of questionable versus mild
dementia based on the CDR-FTLD. The CDR-FTLD, FIQ, FBI, and FRS
predicted 71.3% of the variance of the ECAS Total Score. The variance of the
ECAS behavioural score was predicted 74.7% by the FBI, FIQ and age. FRS
was the single variable to predict attrition by 20.4%. In our study there was no
significant difference of ECAS scores between assessments.
The ECAS proved to be a valid test to assess the cognitive and behavioural
impairments in people with early onset dementia without ALS. It was more
sensitive than the ACE-III at detecting dementia in most of the patient groups,
with the exception of the PCA group where they had equal sensitivity. The
ECAS had also equal sensitivity to detect bvFTD, PPA and PCA as an
extensive neuropsychological assessment. It could therefore be used as a first
assessment in early onset dementia clinics.