Publications by authors named "Louise Gagnon"

23 Publications

  • Page 1 of 1

Reversing frontal disinhibition rescues behavioural deficits in models of CACNA1A-associated neurodevelopment disorders.

Mol Psychiatry 2021 Jun 14. Epub 2021 Jun 14.

CHU Ste-Justine Research Center, Montreal, QC, Canada.

CACNA1A deletions cause epilepsy, ataxia, and a range of neurocognitive deficits, including inattention, impulsivity, intellectual deficiency and autism. To investigate the underlying mechanisms, we generated mice carrying a targeted Cacna1a deletion restricted to parvalbumin-expressing (PV) neurons (PV;Cacna1a) or to cortical pyramidal cells (PC) (Emx1;Cacna1a). GABA release from PV-expressing GABAergic interneurons (PV-INs) is reduced in PV;Cacna1a mutants, resulting in impulsivity, cognitive rigidity and inattention. By contrast, the deletion of Cacna1a in PCs does not impact cortical excitability or behaviour in Emx1;Cacna1a mutants. A targeted Cacna1a deletion in the orbitofrontal cortex (OFC) results in reversal learning deficits while a medial prefrontal cortex (mPFC) deletion impairs selective attention. These deficits can be rescued by the selective chemogenetic activation of cortical PV-INs in the OFC or mPFC of PV;Cacna1a mutants. Thus, Cacna1a haploinsufficiency disrupts perisomatic inhibition in frontal cortical circuits, leading to a range of potentially reversible neurocognitive deficits.
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http://dx.doi.org/10.1038/s41380-021-01175-1DOI Listing
June 2021

Quality and Reliability of Publicly Accessible Information on Laser Treatments for Urinary Incontinence: What Is Available to Our Patients?

J Minim Invasive Gynecol 2020 Nov - Dec;27(7):1524-1530. Epub 2020 Jan 9.

Faculty of Medicine, University of Toronto (Ms. Perruzza and Mr. Butti); Department of Obstetrics and Gynecology, Division of Urogynecology, Sunnybrook Health Sciences Centre (Drs. Jolliffe, McCaffrey, Kung, Gagnon, and Lee), University of Toronto, Toronto, Ontario.. Electronic address:

Study Objective: To determine the quality and reliability of the top 20 internet search results for laser treatment of stress urinary incontinence (SUI).

Design: Review of 20 websites.

Setting: N/A.

Patients: None.

Interventions: An internet search with the most popular search engine, Google, was undertaken to identify the top 20 websites for laser treatment of SUI. The DISCERN instrument, Journal of the American Medical Association (JAMA) benchmarks, and Health on the Net Foundation Code of Conduct certification, which are standardized, validated tools for the analysis of website quality, credibility, and transparency, were used independently by 7 healthcare workers. The readability of the information was assessed by a single reviewer using the Flesch-Kincaid Grade Level and Automated Readability Index. The intraclass correlation coefficient was calculated to document the reliability among website assessors.

Measurements And Main Results: Of the 20 websites reviewed, 15 were created by private clinics, 2 by online newspaper or newsletter sites, and 3 by laser medical device manufacturers. None of the websites met all of the JAMA criteria: 1 had attained authorship, 1 had clear attribution, none had adequate disclosure, and 2 achieved currency. None of the websites took part in the Health on the Net Foundation Code of Conduct certification program. The mean DISCERN score (to determine the quality of websites) was 40 (out of 80), with the lowest average scores within the DISCERN tool primarily associated with clarity around sources of information, website bias, posting dates, risks of treatment, and shared treatment decision-making. The intraclass correlation coefficient was calculated for the DISCERN tool (0.72; 95% confidence interval, 0.48-0.87) and JAMA benchmarks (0.85; 95% confidence interval, 0.73-0.93). The mean Flesch-Kincaid Grade Level was 13.2 (±3.1) and the Automated Readability Index scores ranged from 7.6 to 22.8 (mean 13.5 ± 3.5).

Conclusion: There is a lack of good quality, reliable, and unbiased information available to patients on laser treatment of SUI on the most commonly searched websites. Information is presented at a reading level that is above that of the average reader, which may indicate that patients will have trouble comprehending the information.
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http://dx.doi.org/10.1016/j.jmig.2020.01.001DOI Listing
February 2021

Psychosocial Features of Neurofibromatosis Type 1 in Children and Adolescents.

J Child Neurol 2018 03 10;33(3):225-232. Epub 2018 Jan 10.

2 Department of Pediatric, Centre Hospitalier Universitaire Sainte-Justine, Montreal, Quebec, Canada.

Neurofibromatosis type 1 (NF1) is a common neurologic condition associated with a wide variety of developmental deficits that have an important impact on children and adolescents.

Objective: This article aims to document the psychosocial features of NF1 and to report the interventions described to address the needs of pediatric patients with NF1.

Methods: A literature review was conducted concerning the social life, mental health, and quality of life (QOL) of children and adolescents with NF1 as well as the psychosocial interventions addressed to this population.

Results: Compared to unaffected children and adolescents of the general population, pediatric patients with NF1 have an increased risk of having social difficulties, mental health disorders, behavioral and emotional problems, as well as diminished QOL. Only 3 articles describe interventions within the NF1 population to address these difficulties.

Conclusion: There is a need to develop and assess psychosocial interventions for patients with NF1.
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http://dx.doi.org/10.1177/0883073817749367DOI Listing
March 2018

CACNA1A haploinsufficiency causes cognitive impairment, autism and epileptic encephalopathy with mild cerebellar symptoms.

Eur J Hum Genet 2015 Nov 4;23(11):1505-12. Epub 2015 Mar 4.

Department of Pediatrics, Neurology Service, CHU Ste-Justine, U. de Montréal, Montreal, Quebec, Canada.

CACNA1A loss-of-function mutations classically present as episodic ataxia type 2 (EA2), with brief episodes of ataxia and nystagmus, or with progressive spinocerebellar ataxia (SCA6). A minority of patients carrying CACNA1A mutations develops epilepsy. Non-motor symptoms associated with these mutations are often overlooked. In this study, we report 16 affected individuals from four unrelated families presenting with a spectrum of cognitive impairment including intellectual deficiency, executive dysfunction, ADHD and/or autism, as well as childhood-onset epileptic encephalopathy with refractory absence epilepsy, febrile seizures, downbeat nystagmus and episodic ataxia. Sequencing revealed one CACNA1A gene deletion, two deleterious CACNA1A point mutations including one known stop-gain and one new frameshift variant and a new splice-site variant. This report illustrates the phenotypic heterogeneity of CACNA1A loss-of-function mutations and stresses the cognitive and epileptic manifestations caused by the loss of CaV2.1 channels function, presumably affecting cerebellar, cortical and limbic networks.
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http://dx.doi.org/10.1038/ejhg.2015.21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4613477PMC
November 2015

Neuropsychological functioning in children with temporal lobe epilepsy and hippocampal atrophy without mesial temporal sclerosis: a distinct clinical entity?

Epilepsy Behav 2015 Mar 16;44:17-22. Epub 2015 Jan 16.

Centre de Recherche du CHU Sainte-Justine, 3175 Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1C5, Canada; Centre de Recherche en Neuropsychologie et Cognition (CERNEC), Département de Psychologie, Université de Montréal, 90 Avenue Vincent-d'Indy, Montréal, QC H2V 2S9, Canada. Electronic address:

Unilateral hippocampal atrophy (HA) is considered as a precursor of mesial temporal sclerosis (MTS) in some patients with temporal lobe epilepsy. However, in other cases, it has been suggested that HA without MTS may constitute a distinct epileptic entity. Hippocampal atrophy without MTS was defined as HA without T2-weighted hyperintensity, loss of internal architecture, or associated lesion seen on the MRI data. To date, no study has focused on the cognitive pattern of children with epilepsy with HA without MTS. The objectives of the present study were to characterize the cognitive profile of these children and to investigate the presence (or the absence) of material-specific memory deficits in these young patients, as found in patients with MTS. Toward this end, 16 young patients with epilepsy with either left or right HA without MTS completed a set of neuropsychological tests, assessing overall intelligence, verbal memory and nonverbal memory, and some aspects of attention and executive functions. Results showed normal intellectual functioning without specific memory deficits in these patients. Furthermore, comparison between patients with left HA and patients with right HA failed to reveal a material-specific lateralized memory pattern. Instead, attention and executive functions were found to be impaired in most patients. These results suggest that HA may constitute a distinct epileptic entity, and this information may help health-care providers initiate appropriate and timely interventions.
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http://dx.doi.org/10.1016/j.yebeh.2014.12.023DOI Listing
March 2015

Superior estimation abilities in two autistic spectrum children.

Cogn Neuropsychol 2010 May 13;27(3):261-76. Epub 2010 Oct 13.

Hôpital Rivière-des-Prairies, Centre d'Excellence en Troubles Envahissants du Développement de l'Université de Montréal, Montréal, Canada.

Anecdotal reports of superior estimation abilities in autistic individuals (e.g., Sacks, 1985) have never been confirmed empirically. We present here case studies of 2 children with autistic spectrum diagnoses and report remarkable abilities in estimation for several quantifiable dimensions. K.T. and G.T. were tested at 9 years of age for estimation of rank, numerosity, time, weight, length, surface, distance, and precise enumeration for small numbers. Their performances were compared to those of 6 age- and IQ- matched comparison children. K.T. demonstrated a superior level of performance in estimating rank (e.g., which set has larger numerosity?) but his performance in other tasks was average. G.T. displayed outstanding performance in estimating numerosity, time, weight, surface, length, and distance, with average performance in other tasks. These results show that certain autistic spectrum individuals may develop superior and highly specialized abilities in estimation. We discuss these findings in relation to the role of "veridical mapping" in the development of special ability (Mottron, Dawson, & Soulieres, 2009; Mottron, Dawson, Soulieres, Hubert, & Burack, 2006a). Veridical mapping is the detection of isomorphism within a code, between two codes, or between one code and isomorphic elements of the world. Within this framework, it is proposed that estimation abilities, like absolute pitch, rely on the ability to map a verbal code with a specific magnitude of a psychophysical dimension.
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http://dx.doi.org/10.1080/02643294.2010.519228DOI Listing
May 2010

Near-infrared spectroscopy as an alternative to the Wada test for language mapping in children, adults and special populations.

Epileptic Disord 2007 Sep 20;9(3):241-55. Epub 2007 Sep 20.

Centre de Recherche du Centre Hospitalier Sainte-Justine, Montréal, Qc, Canada.

The intracarotid amobarbital test (IAT) is the most widely used procedure for pre-surgical evaluation of language lateralization in epileptic patients. However, apart from being invasive, this technique is not applicable in young children or patients who present mental retardation and/or language deficits. Functional magnetic resonance imaging (fMRI) is increasingly employed as a non-invasive alternative. Again, this method is more difficult to use with young children, especially hyperactive ones, since they have to remain motionless during data acquisition. The aim of this study was to determine whether near-infrared spectroscopy (NIRS) can be used as an alternative technique to investigate language lateralization in children and special populations. Unlike Wada test, NIRS is non-invasive, and it is more tolerant to movement artefacts than fMRI. In the present study, NIRS data were acquired in four epileptic children, a 12-year-old boy with pervasive developmental disorder and a 3-year-old, healthy child, as well as three healthy and two epileptic adults, while they performed a verbal fluency task and a control task. When applicable, the results were compared to the subjects' fMRI and/or IAT findings. Clear laterality of speech was obtained in all participants, including the two non-epileptic children, and NIRS results matched fMRI and IAT findings. These results, if replicable in larger samples, are encouraging and suggest that NIRS has the potential to become a viable, non-invasive alternative to IAT and fMRI in the determination of speech lateralization in children and clinical populations that cannot be submitted to more invasive techniques.
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http://dx.doi.org/10.1684/epd.2007.0118DOI Listing
September 2007

Quantification judgement in high functioning autism: superior or different?

J Autism Dev Disord 2004 Dec;34(6):679-89

Département de Psychologie, Université de Montréal, Canada.

This study examined the hypothesis of superior quantification abilities of persons with high functioning autism (HFA). Fourteen HFA individuals (mean age: 15 years) individually matched with 14 typically developing (TD) participants (gender, chronological age, full-scale IQ) were asked to quantify as accurately and quickly as possible numerosities, represented by the number of squares (2-9) presented in random configurations. In addition, the visual angles of stimuli presentation were manipulated in order to induce a local (large visual angle) and a global (small visual angle) bias on participants' quantification performance (accuracy and naming time). Findings revealed no effect of local and global bias of stimuli presentation in the two groups' performance, and no superior quantification abilities in HFA participants. However, analyses of the naming time slopes for identification by HFA participants of small consecutive numerosities (2-5), suggested their use of counting processes instead of subitizing (or immediate apprehension of numerosities) as in TD participants. Possible explanations for these results are discussed with reference to models of locally-oriented information processing in autism.
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http://dx.doi.org/10.1007/s10803-004-5288-9DOI Listing
December 2004

Processing of metaphoric and non-metaphoric alternative meanings of words after right- and left-hemispheric lesion.

Brain Lang 2003 Nov;87(2):217-26

Département de Psychologie, Université de Montréal, Montréal, Canada.

This study examines the specificity of the contribution of the right hemisphere to the processing of metaphoric meaning of words. Ten right- and 10 left-hemisphere-damaged subjects, and 20 normal control subjects were submitted to: (1) a word-triad task where they had to associate alternative metaphoric and non-metaphoric words to a target word, and to (2) a word-dyad task where they had to decide whether or not there was a semantic relationship between two words. The two tasks aimed at differentiating between the subjects' preference for a given semantic meaning versus a genuine semantic deficit for a particular meaning. Results revealed that both right- and left-hemisphere-damaged groups presented a genuine semantic deficit for the processing of metaphoric meaning. The absence of a double dissociation between the two brain-damaged groups does not support the hypothesis of a specific contribution of the right-hemisphere to the processing of metaphoric meaning of words.
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http://dx.doi.org/10.1016/s0093-934x(03)00057-9DOI Listing
November 2003
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