Publications by authors named "Alexe Simard"

5 Publications

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Performance of Ultrasound for Identifying Morphological Characteristics and Thickness of Cutaneous Basal Cell Carcinoma: A Systematic Review.

Dermatology 2022 Jan 13:1-19. Epub 2022 Jan 13.

Institute for Diagnostic Imaging and Research of the Skin and Soft Tissues, Santiago, Chile.

Advances in ultrasound technology and non-surgical treatments of basal cell carcinomas (BCCs) have raised the need to study the performance of high-frequency ultrasound (HFUS) in BCCs. We aimed to assess the performance of HFUS in the evaluation of BCCs to formulate recommendations for its uses and conducted a systematic review of the literature to do so. A search of Central, Medline, Embase, CINHAL, and Web of Science was performed using key/MESH terms "ultrasonography" and "basal cell carcinoma" (January 2005-December 2020). We included primary studies reporting biopsy-confirmed BCCs for which the target intervention was ultrasound assessment at 15 MHz or higher frequency. Thirty articles were included, studying a total of 1,203 biopsy-confirmed BCCs. HFUS provides accurate depth measurements, especially for BCCs >1 mm. The definition of lateral margins in vivo needs further studies; however, ex vivo margin assessment seems convincing. There is a diagnostic role for HFUS in identifying higher recurrence risk BCC subtypes, which can help in risk stratification. Performance of HFUS is significant in BCC management. Pre-surgical scans may support case selection for Mohs. HFUS can improve safety when used to plan brachytherapy treatments, help with case selection and adjunct treatment choice pre-photodynamic therapy. Finally, HFUS can help follow lesions after intervention, particularly non-surgical management, and support the decision to observe or re-intervene. HFUS can enhance clinical practice by providing useful information that cannot be deducted from the clinical examination. It would be recommended to evaluate the extent, mainly depth, and detect the aggressiveness of the BCCs.
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http://dx.doi.org/10.1159/000520751DOI Listing
January 2022

Sex differences in the developing brain impact stress-induced epileptogenicity following hyperthermia-induced seizures.

Neurobiol Dis 2021 Dec 4;161:105546. Epub 2021 Nov 4.

Centre de Recherche, Centre Hospitalier Universitaire (CHU) Sainte-Justine, Département de Pédiatrie, Université de Montréal, Québec, Canada; Département de Neurosciences, Université de Montréal, Québec, Canada; Neurosurgery Service, Department of Surgery, Université de Montréal, Québec, Canada.

Febrile seizures (FS) are common, affecting 2-5% of children between the ages of 3 months and 6 years. Complex FS occur in 10% of patients with FS and are strongly associated with mesial temporal lobe epilepsy. Current research suggests that predisposing factors, such as genetic and anatomic abnormalities, may be necessary for complex FS to translate to mesial temporal lobe epilepsy. Sex hormones are known to influence seizure susceptibility and epileptogenesis, but whether sex-specific effects of early life stress play a role in epileptogenesis is unclear. Here, we investigate sex differences in the activity of the hypothalamic-pituitary-adrenal (HPA) axis following chronic stress and the underlying contributions of gonadal hormones to the susceptibility of hyperthermia-induced seizures (HS) in rat pups. Chronic stress consisted of daily injections of 40 mg/kg of corticosterone (CORT) subcutaneously from postnatal day (P) 1 to P9 in male and female rat pups followed by HS at P10. Body mass, plasma CORT levels, temperature threshold to HS, seizure characteristics, and electroencephalographic in vivo recordings were compared between CORT- and vehicle (VEH)-injected littermates during and after HS at P10. In juvenile rats (P18-P22), in vitro CA1 pyramidal cell recordings were recorded in males to investigate excitatory and inhibitory neuronal circuits. Results show that daily CORT injections increased basal plasma CORT levels before HS and significantly reduced weight gain and body temperature threshold of HS in both males and females. CORT also significantly lowered the generalized convulsions (GC) latency while increasing recovery time and the number of electrographic seizures (>10s), which had longer duration. Furthermore, sex-specific differences were found in response to chronic CORT injections. Compared to females, male pups had increased basal plasma CORT levels after HS, longer recovery time and a higher number of electrographic seizures (>10s), which also had longer duration. Sex-specific differences were also found at baseline conditions with lower latency to generalized convulsions and longer duration of electrographic seizures in males but not in females. In juvenile male rats, the amplitude of evoked excitatory postsynaptic potentials, as well as the amplitude of inhibitory postsynaptic currents, were significantly greater in CORT rats when compared to VEH littermates. These findings not only validate CORT injections as a stress model, but also show a sex difference in baseline conditions as well as a response to chronic CORT and an impact on seizure susceptibility, supporting a potential link between sustained early-life stress and complex FS. Overall, these effects also indicate a putatively less severe phenotype in female than male pups. Ultimately, studies investigating the biological underpinnings of sex differences as a determining factor in mental and neurologic problems are necessary to develop better diagnostic, preventative, and therapeutic approaches for all patients regardless of their sex.
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http://dx.doi.org/10.1016/j.nbd.2021.105546DOI Listing
December 2021

Psychometric properties of a color-shape version of the switch task.

Appl Neuropsychol Adult 2020 Dec 9:1-10. Epub 2020 Dec 9.

School of Kinesiology and Exercise Science, Université de Montréal, Montreal, Canada.

The current study aims to examine the psychometric properties of a color-shape version of the switch task. In Study 1, 128 participants completed a battery of standardized measures of executive functions (EFs) as well as the switch task to determine the construct validity of three traditionally computed costs (global, switch, and mixing) and primary variables (accuracy [ACC], reaction time [RT], and inverse efficiency score [IES] of the heterogeneous condition). In Study 2, 48 participants completed the task twice, seven days apart, to evaluate its short-term test-retest reliability. Results do not support the construct validity and the test-retest reliability of switch and mixing costs. The overall higher psychometric properties of the global costs (RT and IES), and primary variables (Hetero RT and IES) suggest that they may be useful measures for clinicians to assess EFs. The latter variables show evidence of convergent validity with standardized measures of EFs and good test-rest reliability (ICC ≥ .68).
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http://dx.doi.org/10.1080/23279095.2020.1842410DOI Listing
December 2020

Practice effect associated with the serial administration of the switch task and its implications in the assessment of sports-related concussion.

J Clin Exp Neuropsychol 2020 11 11;42(9):965-973. Epub 2020 Oct 11.

School of Kinesiology and Exercise Science, Université de Montréal , Montreal, Quebec, Canada.

In the context of return to play assessment following a sports concussion, athletes may have to complete a cognitive task several times within days. The current longitudinal study aimed to examine the practice effect associated with the serial administration of the switch task. We hypothesized that the practice effect would be the greatest between the first and second assessments and that a plateau would be obtained by the third assessment. Forty healthy university students completed the switch task four times at an interval of 48-hour, with half of them doing version A on all visits (AA group), while the others alternated between A and B every other assessment (AB group). For response accuracy, performance generally improved from V1 to V2, and from V2 to V3 ( ≤.001), irrespective of group. For reaction time, a significant interaction of Visit × Group was observed. Specifically, AA group performance improved from V1 to V2, and from V2 to V3, while the AB group only improved from V2 to V3 ( ≤.01). Performance improved over the first three assessments and stabilized with no statistically significant change between the third and fourth testing sessions. Although the use of an alternative version has helped reduce the practice effect, it did not help in eliminating it. The current results highlight the need for further examination of the practice effect and its implication in clinical decision-making. Clinicians working in the sports concussion field must take the practice effect into account when they use the switch task for serial testing.
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http://dx.doi.org/10.1080/13803395.2020.1828836DOI Listing
November 2020

Favorable adverse effect profile of brivaracetam vs levetiracetam in a preclinical model.

Epilepsy Behav 2018 02 26;79:117-125. Epub 2017 Dec 26.

Centre de Recherche, Centre Hospitalier Universitaire CHU-Sainte-Justine, Québec, Canada; Département de Neurosciences, Faculté de Médecine, Université de Montréal, Québec, Canada. Electronic address:

Levetiracetam (LEV), and its newer selective analog brivaracetam (BRV), are two seizure medications that share an innovative mechanism of action targeting the Synaptic Vesicle Protein 2A (SV2A), altering neurotransmitter release and decreasing seizure frequency. Behavioral changes are the most significant adverse effects reported by patients taking LEV. We hypothesize that BRV, the more potent SV2A analog, could exert less behavioral side effects, as it requires lower doses than LEV. Using Kainic Acid (KA)-treated and control rats, we measured adverse behavioral effect profiles of LEV, BRV, or Saline, on social and nonsocial behaviors. Our data indicate that both tested drugs had no effect on locomotion, anxiety levels, fear learning, depression-like behavior, and memory retention in rats. However, when considering social interactions, we first confirmed the epilepsy-induced strong increase in aggressive behaviors and specific hippocampal neuronal loss. We furthermore observed, in Sham rats, that LEV-treated animals were 2 times faster to attack at first encounter, had 5 times more aggressive behaviors, and had significantly less social behaviors than control rats. In all circumstances, BRV rats behaved like Saline rats, suggesting that BRV treatment in rats leads to significantly less aggressive behaviors than LEV treatment at the doses used, while there are limited differential effects between these two drugs on other types of behaviors. Since increased aggressiveness has been reported in patients well controlled on LEV, this study indicates based on our findings, that BRV could represent an effective alternative to LEV to limit aggressiveness problems due to this antiepileptic drug (AED) therapy.
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http://dx.doi.org/10.1016/j.yebeh.2017.11.019DOI Listing
February 2018
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