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Related Experiment Video

Updated: Dec 22, 2025

Examining the Characteristics of Episodic Memory using Event-related Potentials in Patients with Alzheimer's Disease

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Altered Time Awareness in Dementia.

Maï-Carmen Requena-Komuro¹, Charles R Marshall^1,2, Rebecca L Bond¹

¹Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom.

Frontiers in Neurology

|May 7, 2020

Summary

This summary is machine-generated.

Altered time awareness is common in dementia, with distinct patterns observed in frontotemporal dementia syndromes and Alzheimer's disease. This study identifies specific temporal symptoms linked to different dementia types.

Keywords:

Alzheimer's disease clockwatching frontotemporal dementia primary progressive aphasia semantic dementia time perception voxel-based morphometry

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Area of Science:

Neuroscience
Gerontology
Psychology

Background:

Time awareness is crucial for self-continuity.
Disrupted time awareness is a feature of frontotemporal dementia (FTD) and Alzheimer's disease (AD).
Systematic comparison of temporal awareness deficits across FTD syndromes and AD is lacking.

Purpose of the Study:

To systematically compare temporal awareness symptoms across major FTD syndromes, typical AD, logopenic aphasia, and healthy controls.
To identify clinical syndromic signatures of altered time awareness.
To explore neurobiological correlates of temporal awareness disturbances using voxel-based morphometry.

Main Methods:

A semi-structured caregiver survey assessed time-related behavioral alterations in 71 FTD patients, 28 AD patients, 9 logopenic aphasia patients, and 32 healthy controls.
Logistic regression analyzed symptom prevalence across diagnostic groups, controlling for age, gender, and disease severity.
Voxel-based morphometry investigated associations between altered time awareness and gray matter structure.

Main Results:

All patient groups showed significantly more temporal awareness symptoms than healthy individuals.
Alzheimer's disease and logopenic aphasia patients most frequently had disturbed event ordering or interval estimation.
Semantic dementia patients showed increased temporal rigidity and clockwatching; behavioral variant FTD patients exhibited all symptoms and a propensity to relive past events.
Reliving past events correlated with preserved left temporo-parietal gray matter, including the hippocampus.

Conclusions:

Distinct patterns of disturbed temporal awareness characterize different dementia syndromes, differentiating FTD from AD.
This study provides the first cross-syndrome assessment of temporal awareness symptoms in FTD.
Findings support the development of validated questionnaires, further neurobiological investigation, and targeted interventions for temporal awareness deficits in dementia.