Daniel Saumier

McGill University | McGill · Douglas Mental Health University Institute

Epigenetic research in post-traumatic stress disorder (PTSD) is essential, given that environmental stressors and fear play such a crucial role in its development. As such, it may provide a framework for understanding individual differences in the prevalence of the disorder and in treatment response. This paper reviews the epigenetic markers associ...

Objectives In a sustained relationship, romantic betrayal is a catastrophic event that can precipitate an adjustment disorder (AD). Surprisingly, there exists no empirically validated treatment for AD, despite its high prevalence in clinical practice. Considering the promise of memory reactivation under propranolol (i.e., reconsolidation interferen...

The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) is a structured interview that assesses the frequency and severity of each symptom of posttraumatic stress disorder (PTSD) in relation to a single traumatic stressor over a 1-month period, allowing the trained interviewer to infer a current or lifetime diagnosis congruent with the 5th Edition...

Background: Neuropsychological alterations co-occur with Posttraumatic Stress Disorder (PTSD); yet, the nature and magnitude of such alterations in police officers remains unknown despite their high level of trauma exposure. Objective: The current research sought to examine (1) cognitive functioning among police officers with and without PTSD; (...

Background Traumatic stress is a global mental health problem requiring novel, easily implemented treatment solutions. We compared the effectiveness and efficiency of Reconsolidation Therapy (RT) to the well-established antidepressant paroxetine, in reducing symptoms of traumatic stress among patients from Nepal, a low-income country. Methods Fort...

Lawyers can be exposed to cases involving traumatic elements of crimes. Such exposure may result in symptoms of posttraumatic stress disorder (PTSD) and have adverse effects on the lawyers’ capacities to work. A scoping review was conducted to summarize original investigations of work-related PTSD among lawyers in terms of (a) trauma exposure conce...

Since the advent of the concept of memory reconsolidation, animal and pre-clinical studies on humans using this paradigm have proliferated. However, clinical translation of this knowledge remains scant. Through a carefully designed study involving patients undergoing endoscopy, Galarza Vallejo et al. (2019) show that intravenous administration of a...

Propranolol administered immediately after learning or after recall has been found to impair memory consolidation or reconsolidation (respectively) in animals, but less reliably so in humans. Since reconsolidation impairment has been proposed as a treatment for mental disorders that have at their core an emotional memory, it is desirable to underst...

Background: Propranolol has effectively diminished fear-based emotional memories in posttraumatic stress disorder (PTSD) and this effect has been attributed to traumatic memory reconsolidation blockade. However, propranolol may also exert cognitive effects by modulating stress and arousal. Method: Within a randomized double-blind placebo control...

Background: The reconsolidation blocker propranolol abolishes alcohol and drug-seeking behavior in rodents and attenuates conditioned emotional responses to drug-cues in humans in experimental settings. This suggests a role for its use in the treatment of substance dependence. In this translational pilot study, we explored the feasibility and effi...

Objective: In a previous, double-blind, placebo-controlled study, patients with posttraumatic stress disorder (PTSD) showed lower physiological response during script-driven traumatic imagery 1 week after receiving a single dose of propranolol given after the retrieval of a traumatic memory. We hypothesized that this effect would extend beyond 1 w...

To examine how peritraumatic distress modulates the severity of posttraumatic stress disorder (PTSD) according to the timing of the PTSD symptom assessments. A systematic literature review of English- and French-language studies having administered the Peritraumatic Distress Inventory (PDI) was conducted. Meta-analyses were performed on correlation...

The aim of the study was to assess the clinical efficacy, safety, and disease-modification effects of tramiprosate (homotaurine, ALZHEMED(TM)) in mild-to-moderate Alzheimer's disease (AD). Double-blind, placebo-controlled, randomized trial in 67 clinical centres across North America. Patients aged ≥ 50 years, with mild-to-moderate AD (Mini-Mental S...

The current investigation sought to ellucidate the nature of the visual shape information responsible for the categorical perception of face stimuli (Rossion, Schiltz, Robaye, Pirenne & Crommelinck, 2001). A series of 11 faces corresponding to a linear continuum of morphed faces whose extremities consisted of specific facial identities was produced...

Tramiprosate (homotaurine, ALZHEMEDTM) was recently investigated for its efficacy, safety and disease-modification effects in a Phase III clinical study in mild to moderate Alzheimer's disease (AD) patients (the Alphase study). The primary cognitive endpoint measure of that study was the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS...

The assessment of patient outcomes in clinical trials of new therapeutics for Alzheimer's disease (AD) continues to evolve. In addition to assessing drugs for symptomatic relief, an increasing number of trials are focusing on potential disease-modifying agents. Moreover, participants with AD are being studied earlier in their course of disease. As...

The efficacy, safety and disease-modification of tramiprosate (homotaurine)were investigated in a recently completed large-scale Phase III clinical study in patients with mild to moderate Alzheimer's disease (AD), the Alphase study. Disease-modification was assessed using longitudinal volumetric MRI (vMRI) measurements of the hippocampus in a subgr...

Previous research has demonstrated impairment in comprehension of emotional prosody in individuals diagnosed with Alzheimer's disease (AD). The present pilot study further explored the prosodic processing impairment in AD, aiming to extend our knowledge to encompass both grammatical and emotional prosody processing. As expected, impairments were se...

Semantic memory is the component of long-term memory that stores our concepts about the world. The disruption of semantic memory as a result of brain damage may have profound negative consequences on an individual's ability to name objects and process concepts. This can be disrupted as a result of many forms of brain damage, particularly Alzheimer'...

As a potential disease-modifying treatment for AD, Alzhemed (tramiprosate) is a compound that binds to soluble amyloid-beta peptide (Abeta) and inhibits the formation of neurotoxic aggregates that lead to amyloid plaque deposition in the brain. The safety, tolerability, and pharmacodynamic effects of Alzhemed were assessed in a double-blind study i...

A diminished top-down influence has been proposed in autism, to account for enhanced performance in low-level perceptual tasks. Applied to perceptual categorization, this hypothesis predicts a diminished influence of category on discrimination. In order to test this hypothesis, we compared categorical perception in 16 individuals with and 16 indivi...

To examine whether the presence of domain-specific cognitive impairments would predict a response to donepezil medication in patients with mild-to-moderate Alzheimer disease (AD). The protocol was an open-label study of 30 AD subjects (mean age 74 years; education 11 years; Mini-Mental State Exam (MMSE) 23 of 30) beginning a 6-month course of treat...

As a potential disease-modifying treatment for Alzheimer disease (AD), 3-amino-1-propanesulfonic acid (3APS) is a compound that binds to amyloid beta (Abeta), a toxic protein known to aggregate, leading to amyloid plaque deposition in the brain. We assessed the safety, tolerability, and pharmacokinetic/pharmacodynamic effect of 3APS in a randomized...

Configural processing in autism was studied in Experiment 1 by using the face inversion effect. A normal inversion effect was observed in the participants with autism, suggesting intact configural face processing. A priming paradigm using partial or complete faces served in Experiment 2 to assess both local and configural face processing. Overall,...

Alzheimer's disease (AD) subjects, healthy elderly, and young adults interpreted a series of novel noun-noun expressions composed of familiar object words. Subjects interpreted each item by selecting one of three possible definitions: a definition in which the referents of each noun were associated together in a particular context (e.g., rabbit cat...

Individuals with Alzheimer's disease (AD) often have problems in recognizing common objects. This visual agnosia may stem from difficulties in establishing appropriate visual boundaries between visually similar objects. In support of this hypothesis, showed that AD subjects have difficulties in establishing visual category boundaries between contin...

Semantic and syntactic contributions to processing of mass and count nouns were assessed by examining the performance of a patient suffering from a pure semantic deficit. Semantic and syntactic processing was evaluated on grammaticality judgement and sentence-picture matching tasks, respectively, where each task involved mass and count readings of...

Reaction time (RT) tasks take various forms, and can assess psychomotor speed, (i.e., simple reaction time task), and focused attention (i.e., choice reaction time (CRT) task). If cues are provided before stimulus presentation (i.e., cued choice reaction time (CCRT) task), then a cueing effect can also be assessed. A limited number of studies have...

A visual search experiment using synthetic three-dimensional objects is reported. The target shared its constituent parts, the spatial organization of its parts, or both with the distractors displayed with it. Sharing of parts and sharing of spatial organization both negatively affected visual search performance, and these effects were strictly add...

In a series of visual search experiments involving simple 2D shapes, Arguin and Saumier (2000) showed that targets that were made of conjunctions of distractor features or that were a linear combination of distractor features were searched at significantly slower rates than single-feature linearly separable targets. The present study assessed wheth...

Our concepts about objects, states, and events are stored in a cognitive structure termed semantic memory. There are several types of neurologic disorders that may cause impairments of semantic memory. Clinical evaluations of these impairments are complex, because semantic memory is linked to other cognitive systems that, when damaged, may produce...

Current models of vision generally assume that the recognition of visual objects is achieved by encoding their component parts, as well as the spatial relations among parts. The current study examined how the processing of parts and their configurations may be affected in visual agnosia due to brain damage. Both a visual agnosic patient (AR) and he...

An ongoing issue in face recognition research is whether holistic face processing relies on the segregation of local discrete facial parts. Evidence in favor of the holistic-plus-parts view stems from a recent study reported by Arguin and Saumier (1999), who show that the priming effects of individual facial parts (i.e., eyes, nose, mouth, orcontou...

Although the principles defining HIT find support within a variety of fields, the framework is currently underspecified in several respects, which prevents it from fully achieving its purpose. We highlight a number of such shortcomings and propose avenues for a resolution of some of these issues.

Four visual search experiments are reported which used simple 2D shapes varying on the global dimensions of aspect ratio/curvature or aspect ratio/tapering. Results indicate serial self-terminating search in all conditions. Most importantly, search rates are markedly modulated by the particular forms of structural relations existing between the tar...

Dans cette étude, nous avons voulu distinguer deux aspects de la familiarité des concepts: la familiarité avec le sens des mots et la familiarité avec leur référent. La familiarité avec le sens a été mesurée en demandant aux sujets d'évaluer la facilité avec laquelle ils pourraient identifier une définition des mots présentés. La familiarité avec l...