Social cognition differentiates phenocopy syndrome of behavioural variant frontotemporal dementia from behavioural variant frontotemporal dementia

Marie-Paule E van Engelen; Paulette Louwers; Jay L P Fieldhouse; Flora T Gossink; Sterre C M de Boer; Annemieke Dols; Philip Scheltens; Sigfried N T M Schouws; Yolande A L Pijnenburg; Everard G B Vijverberg; Welmoed A Krudop

doi:10.1111/psyg.13107

Social cognition differentiates phenocopy syndrome of behavioural variant frontotemporal dementia from behavioural variant frontotemporal dementia

Psychogeriatrics. 2024 Apr 2. doi: 10.1111/psyg.13107. Online ahead of print.

Authors

Marie-Paule E van Engelen^{1

2}, Paulette Louwers^{1

2}, Jay L P Fieldhouse^{1

2}, Flora T Gossink³, Sterre C M de Boer^{1

2

4}, Annemieke Dols^{5

6}, Philip Scheltens^{1

2

7}, Sigfried N T M Schouws^{8

9

10}, Yolande A L Pijnenburg^{1

2}, Everard G B Vijverberg^{1

2}, Welmoed A Krudop^{1

8}

Affiliations

¹ Alzheimer Centre Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC location VUmc, Amsterdam, The Netherlands.
² Amsterdam Neuroscience, Neurodegeneration, Amsterdam, The Netherlands.
³ Reinier van Arkel, Jeroen Bosch Hospital, Hospital and Geriatric Psychiatric Centre, Den Bosch, The Netherlands.
⁴ The University of Sydney, School of Psychology, Sydney, New South Wales, Australia.
⁵ Department of Psychiatry, University Medical Centre Utrecht, Utrecht, The Netherlands.
⁶ Department of Psychiatry, Amsterdam Neuroscience, Mood Anxiety Psychosis Sleep & Stress Program, Amsterdam UMC, Amsterdam, The Netherlands.
⁷ EQT Life Sciences Partners, Amsterdam, The Netherlands.
⁸ Department of Old Age Psychiatry and Neuropsychiatry, GGZ inGeest Specialised Mental Health Care, Location De Nieuwe Valerius, Amsterdam, The Netherlands.
⁹ Amsterdam UMC Location Vrije Universiteit Amsterdam, Psychiatry, Amsterdam, The Netherlands.
¹⁰ Amsterdam Public Health Research Institute, Mental Health, Amsterdam, The Netherlands.

PMID: 38566489
DOI: 10.1111/psyg.13107

Abstract

Background: Patients displaying clinical features of behavioural variant of frontotemporal dementia (bvFTD) but lacking both neuroimaging abnormalities and clinical progression are considered to represent the phenocopy syndrome of bvFTD (phFTD). Extensive clinical overlap between early phase bvFTD and phFTD hampers diagnostic distinction. We aimed to assess the diagnostic value of clinician-rated, self-reported and caregiver-reported symptoms for clinical distinction between phFTD and bvFTD.

Methods: There were 33 phFTD and 95 probable bvFTD patients included in the study (total N = 128). Clinician-rated, self-reported tests and caregiver-reported symptoms were compared between phFTD and bvFTD on social cognition, behaviour, mood and activities of daily living (ADL). Scores were compared between groups, followed by multiple logistic regression analysis, adjusted for age and sex. Receiver operating characteristic curves were plotted to assess diagnostic value.

Results: Using clinician-rated and self-reported tests, phFTD patients performed better on facial emotion recognition and reported more depressive symptoms. Caregiver-reported behavioural symptoms indicated higher behavioural and ADL impairment in phFTD compared to bvFTD. Facial emotion recognition provided highest diagnostic accuracy for distinction of phFTD from bvFTD (area under the curve (AUC) 0.813 95% CI 0.735-0.892, P < 0.001, sensitivity 81%, specificity 74%) followed by depressive symptoms (AUC 0.769 95% 0.674-0.864, P < 0.001 sensitivity 81%, specificity of 63%).

Conclusion: Social cognition tests are most suitable for distinction of phFTD from bvFTD. Caregiver-reported questionnaires and phFTD diagnosis seemed inversely correlated, showing more symptoms in phFTD. Further research is needed on phFTD aetiology and in caregivers taking into account disease burden to assess what explains this discrepancy between clinician-rated and caregiver-based tools.

Keywords: diagnostics; frontotemporal dementia; phenocopy FTD; social cognition.