Voluntary Imitation in Alzheimer’s Disease Patients

Abstract

Although Alzheimer’s disease (AD) primarily manifests as cognitive deficits, the implicit sensorimotor processes that underlie social interactions, such as automatic imitation, seem to be preserved in mild and moderate stages of the disease, as is the ability to communicate with other persons. Nevertheless, when AD patients face more challenging tasks, which do not rely on automatic processes but on explicit voluntary mechanisms and require the patient to pay attention to external events, the cognitive deficits resulting from the disease might negatively affect patients’ behavior. The aim of the present study was to investigate whether voluntary motor imitation, i.e., a volitional mechanism that involves observing another person’s action and translating this perception into one’s own action, was affected in patients with AD. Further, we tested whether this ability was modulated by the nature of the observed stimulus by comparing the ability to reproduce the kinematic features of a human demonstrator with that of a computerized-stimulus. AD patients showed an intact ability to reproduce the velocity of the observed movements, particularly when the stimulus was a human agent. This result suggests that high-level cognitive processes involved in voluntary imitation might be preserved in mild and moderate stages of AD and that voluntary imitation abilities might benefit from the implicit interpersonal communication established between the patient and the human demonstrator.

Postural Stabilization Strategies to Motor Contagion Induced by Action Observation Are Impaired in Parkinson’s Disease

“…This behavior could be the consequence either of an inability to inhibit automatic imitative tendencies or of the cognitive load requested by the task. We favor the first hypothesis since the cognitive load requested by the task was limited as indicated by the preserved ability to perform similar tasks in patients with cognitive deficits due to Alzheimer’s disease ( 77 ). However, since we did not insert a control condition displaying a “scrambled” animation, not a biological motion, but requiring attentional load ( 9 ), in our experimental protocol, future studies are needed to better discern between these two explanations.…”

Mirror neurons and their relationship with neurodegenerative disorders

“…In the second experiment (Bisio et al, ), the authors tested voluntary imitation in AD and how this ability was influenced by the nature of the observed stimulus. To this end they compared the capability to reproduce the kinematic features of a human model with that of a dot moving on a screen.…”

Influence of Transcranial Direct Current Stimulation on Psychomotor Symptoms in Major Depression

“…The tasks used in this trial were modified from our previous studies [15][16][17] and are more precisely described by Bennabi et al [18]. All participants were seated in a darkened room in front of a large rear projection screen (170 × 230 cm) placed 10 cm beyond the end of the participant's extended arm.…”

“…Given the limited number of studies on this matter and their inconsistent results, this trial aimed to further investigate the psychomotor effects of tDCS in MDD by applying a simple imitation paradigm. This task is an objective and reliable method to assess motor activity, and it represents a promising and innovative manner to investigate the kinematic features of movements in natural conditions and in perception-action coupling [15][16][17]. It is considered a rater-independent and more precise and objective measurement method than the subjective rating scales.…”