Publications by authors named "Paul S Horn"

Objective: Tuberous sclerosis complex (TSC) results from overactivity of the mechanistic target of rapamycin (mTOR). Sirolimus and everolimus are mTOR inhibitors that treat most facets of TSC but are understudied in infants. We sought to understand the safety and potential efficacy of preventative sirolimus in infants with TSC.

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Treatment studies in knockout rodent models have found that minocycline and lovastatin each improve synaptic, neurological, and behavioral functioning, and open-label chronic dosing studies in human patients with fragile X syndrome (FXS) have demonstrated modest clinical improvements. Findings from blinded studies are mixed, and there is a limited understanding of electrophysiological target engagement that would facilitate cross-species translational studies. Smaller-scale, acute (e.

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Estimating meaningful change thresholds (MCT) on clinical outcome assessments is an important consideration when evaluating treatments. In fragile X syndrome (FXS) research, there has been no consensus on how to define MCT's on several commonly used outcome measures. The purpose of the current study was to determine clinically relevant MCT's of caregiver-rated assessments using data from a phase 3 clinical trials of arbaclofen (Berry-Kravis et al.

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Introduction: Autistic children and adolescents frequently experience emotion dysregulation, or difficulties with appropriately modifying their emotional reactions. Caregivers of autistic teens frequently seek psychotherapy support for navigating challenges associated with emotion dysregulation. During the COVID-19 pandemic, access to clinical services became limited, with interventions halted or transitioned into a telehealth format.

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Background: Only 5% of aquaporin-4-positive neuromyelitis optica spectrum disorder (AQP4+ NMOSD) cases emerge during childhood. Poorer outcomes have been suggested in black/African American (AA) adults with NMOSD; however, conflicting and limited data exist for pediatric-onset NMOSD. This study evaluates racial, ethnic, and socioeconomic disparities in pediatric AQP4+ NMOSD outcomes.

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Article Synopsis
  • The study investigates how different areas of the cerebral cortex exhibit varying daily rhythms of high-frequency oscillations (HFOs) in patients with drug-resistant epilepsy.
  • Stereotactic electroencephalography (EEG) was used to analyze HFOs across different brain regions, while filtering out data affected by seizures or artifacts.
  • Five distinct clusters were identified based on HFO patterns, which aligned with specific resting-state brain networks, suggesting a link between time-of-day variations in brain activity and functional connectivity.
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  • The study aimed to assess cognitive changes after surgery that involved removing areas of the brain with significant high-gamma power modulations (HGM) during a visual naming task, even though these areas were not identified as language-critical during standard electrical stimulation mapping.
  • Researchers analyzed the cognitive outcomes of 37 drug-resistant epilepsy patients one year after surgery, highlighting the effects of lesioning HGM language sites on various neuropsychological assessments, specifically measuring reliable change indices (RCIs).
  • Results showed that lesioning even one HGM language site was associated with significant declines in scores for vocabulary, working memory, and verbal learning, indicating that these areas play an important role in cognitive function, despite being categorized as non-language sites through electrical mapping.
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Background: Newer biomarkers of Hepatitis B virus (HBV) infection and treatment response have not been well-characterized in individuals with HBV/HIV coinfection.

Methods: Pre-genomic RNA (pgRNA) and quantitative HBsAg (qHBsAg) were used to evaluate the associations with baseline characteristics. Participants included two separate groups - 236 with HBV/HIV coinfection enrolled in a cross-sectional cohort in Ghana and 47 from an HBV nucleoside/nucleotide treatment trial comparing tenofovir to adefovir in the United States.

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  • Ninety percent of patients with tuberous sclerosis complex (TSC) experience seizures, and about half have epilepsy that doesn't respond to medication.
  • A study explored how the size and number of seizure onset zones (SOZ) affect surgical outcomes in TSC patients who underwent epilepsy surgery.
  • The findings revealed that larger SOZ sizes and having more than one SOZ were linked to poorer surgical outcomes, suggesting that these characteristics could help predict the success of surgery in reducing seizures.
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Missed medical appointments are a common problem across specialties. The discontinuity of care leads to unplanned health care utilization, increased costs, and poor health outcomes. Previous studies evaluating pediatric epilepsy have shown significant socioeconomic barriers to care.

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Autistic youth experience several behavioral and emotional characteristics that can predispose them to emotion dysregulation (ED). Current literature examining ED in autism spectrum disorder (ASD) is limited to parent- and self-reported measures, indicating a need for biological or physiological methods to better assess emotion regulation in ASD. Utilizing the autonomic nervous system, specifically heart rate variability (HRV), may be a promising method to objectively measure ED in ASD, given it is one of the body's primary means of regulating physiological arousal.

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Fragile X syndrome (FXS) is an X-linked disorder that often leads to intellectual disability, anxiety, and sensory hypersensitivity. While sound sensitivity (hyperacusis) is a distressing symptom in FXS, its neural basis is not well understood. It is postulated that hyperacusis may stem from temporal lobe hyperexcitability or dysregulation in top-down modulation.

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Purpose: Major depressive disorder (MDD) disproportionately affects those living with autism spectrum disorder (ASD) and is associated with significant impairment and treatment recidivism.

Methods: We studied the use of accelerated theta burst stimulation (ATBS) for the treatment of refractory MDD in ASD (3 treatments daily x 10 days). This prospective open-label 12-week trial included 10 subjects with a mean age of 21.

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Article Synopsis
  • Acquired epilepsies begin after a brain injury, leading to the gradual development of seizures, but the processes behind this progression (epileptogenesis) are not fully understood; microRNAs like miR-324-5p have been linked to regulating these processes.
  • In a study with mice, researchers tested the effects of inhibiting miR-324-5p during the epileptogenesis phase by using a specific model (IHpKa) and monitoring through EEG for 28 days.
  • The findings showed that inhibiting miR-324-5p did not prevent the onset or severity of seizures but did affect certain EEG activity patterns, suggesting that timing of treatment is crucial and that miR-324-5
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Introduction: Mutations in the 79 exons of the dystrophin gene result in muscle wasting and weakness of varying clinical severity, ranging from severe/typical Duchenne muscular dystrophy (DMD) to intermediate DMD and mild Becker muscular dystrophy (BMD), depending on the frameshift of the mutation. We previously reported that males with DMD have progressively declining appendicular lean mass (ALM) and ALM index (ALMI) with age and worsening functional motor ability compared with healthy controls. These indices have not been studied in patients with intermediate DMD and BMD phenotypes and across DMD genotypes.

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Background And Objectives: The prevalence of generalized joint hypermobility (GJH) is 5-65% in children and adolescents. The hypothesis of this study was to see whether there is an association between headache characteristics and GJH in children and adolescents with migraine.

Methods: We performed a primary retrospective case-control analysis of an established database of patients with headache aged 5-17 years.

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Purpose: The construct Quality of Life (QoL) involves a range of factors related to one's well-being. Individuals on the autism spectrum have been previously reported to have lower QoL. The purpose of the present study is to examine QoL in autistic individuals and their families and to evaluate associations between QoL and measures of functioning using the PedsQL 4.

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Objective: Transcranial Magnetic Stimulation (TMS) has emerged as a viable non-invasive method for mapping language networks. Little is known about the tolerability of transcranial magnetic stimulation language mapping in children.

Methods: Children aged 5-18 years underwent bilateral language mapping using repetitive transcranial magnetic stimulation (rTMS) to target 33 sites/hemisphere.

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Background And Purpose: We analyzed the association of neuropsychological outcomes after epilepsy surgery with the intracranial electrode type (stereo electroencephalography [SEEG] and subdural electrodes [SDE]), and electrical stimulation mapping (ESM) of speech/language.

Methods: Drug-resistant epilepsy patients who underwent comprehensive neuropsychological evaluation before and 1 year after epilepsy surgery were included. SEEG and SDE subgroups were matched by age, handedness, operated hemisphere, and seizure freedom.

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Background And Objectives: The objective of this study was to determine patient-specific factors known proximate to the presentation to emergency care associated with the development of refractory convulsive status epilepticus (RSE) in children.

Methods: An observational case-control study was conducted comparing pediatric patients (1 month-21 years) with convulsive SE whose seizures stopped after benzodiazepine (BZD) and a single second-line antiseizure medication (ASM) (responsive established status epilepticus [rESE]) with patients requiring more than a BZD and a single second-line ASM to stop their seizures (RSE). These subpopulations were obtained from the pediatric Status Epilepticus Research Group study cohort.

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The FMR1 gene is inactive in Fragile X syndrome (FXS), resulting in low levels of FMRP and consequent neurochemical, synaptic, and local circuit neurophysiological alterations in the fmr1 KO mouse. In FXS patients, electrophysiological studies have demonstrated a marked reduction in global alpha activity and regional increases in gamma oscillations associated with intellectual disability and sensory hypersensitivity. Since alpha activity is associated with a thalamocortical function with widely distributed modulatory effects on neocortical excitability, insight into alpha physiology may provide insight into systems-level disease mechanisms.

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Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by core impairments in social communication as well as restricted, repetitive patterns of behavior and/or interests. Individuals with ASD, which includes about 2% of the US population, have challenges with activities of daily living and suffer from comorbid medical and mental health concerns. There are no drugs indicated for the core impairments of ASD.

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Background: Neurofibromatosis type 1 (NF1) is a genetic neurocutaneous disorder commonly associated with motor and cognitive symptoms that greatly impact quality of life. Transcranial magnetic stimulation (TMS) can quantify motor cortex physiology, reflecting the basis for impaired motor function as well as, possibly, clues for mechanisms of effective treatment. We hypothesized that children with NF1 have impaired motor function and altered motor cortex physiology compared to typically developing (TD) control children and children with attention-deficit/hyperactivity disorder (ADHD).

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Article Synopsis
  • - The study aimed to compare the motor cortex function using transcranial magnetic stimulation (TMS) between children with Tourette syndrome and those without, exploring how these measures relate to tic severity.
  • - A total of 60 children, aged 8 to 12, participated, including 30 with Tourette syndrome, with assessments focusing on tic and urge severity, as well as co-occurring conditions like ADHD.
  • - Results showed that while there was no significant difference in motor cortex measures between the two groups, reduced cortical inhibition predicted higher tic severity in those with Tourette syndrome, but did not correlate with urge severity.
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Fragile X syndrome (FXS) is the most common inherited intellectual disability. FXS is caused by a trinucleotide repeat expansion in the 5' untranslated region of the FMR1 gene, which leads to gene methylation, transcriptional silencing, and lack of expression of Fragile X Messenger Riboprotein (FMRP). Currently available FXS therapies are inefficient, and the disease severity is highly variable, making it difficult to predict disease trajectory and treatment response.

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