Publications by authors named "David A Huddleston"

We aimed to compare tic- and non-tic-related impairment experienced by adolescent girls and boys (ages 13 through 17) with Tourette syndrome and associations with age. We extracted from the electronic health record child and parental responses to the mini-Child Tourette Syndrome Impairment Scale (mini-CTIM) and other questionnaire data reflective of tic- and non-tic-related impairment of adolescents with Tourette syndrome presenting to our clinic over a 12-month period. We identified a total of 132 (49 female, 83 male) unique adolescent encounters.

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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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Limited data are available regarding the impact of the coronavirus disease 2019 (COVID-19) pandemic on adolescents with Tourette syndrome (TS). We sought to compare sex differences in tic severity experienced by adolescents before and during the COVID-19 pandemic. We extracted from the electronic health record and retrospectively reviewed Yale Global Tic Severity Scores (YGTSS) from adolescents (ages 13 through 17) with TS presenting to our clinic before (36 months) and during (24 months) the pandemic.

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Tourette syndrome (TS) is a childhood-onset disorder in which tics are often preceded by premonitory sensory urges. More severe urges correlate with worse tics and can render behavioral therapies less effective. The supplementary motor area (SMA) is a prefrontal region believed to influence tic performance.

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Motor inhibition is an important cognitive process involved in tic suppression. As the right frontal lobe contains important inhibitory network nodes, we characterized right superior, middle, and inferior frontal gyral (RSFG, RMFG, RIFG) event-related oscillations during motor inhibition in youth with chronic tic disorders (CTD) versus controls. Fourteen children with CTD and 13 controls (10-17 years old) completed an anticipated-response stop signal task while dense-array electroencephalography was recorded.

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Background: Individuals with Tourette syndrome (TS) often report that they express tics as a means of alleviating the experience of unpleasant sensations. These sensations are perceived as an urge to act and are referred to as premonitory urges. Premonitory urges have been the focus of recent efforts to develop interventions to reduce tic expression in those with TS.

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The stop-signal paradigm has become ubiquitous in investigations of inhibitory control. Tasks inspired by the paradigm, referred to as stop-signal tasks, require participants to make responses on go trials and to inhibit those responses when presented with a stop-signal on stop trials. Currently, the most popular version of the stop-signal task is the 'choice-reaction' variant, where participants make choice responses, but must inhibit those responses when presented with a stop-signal.

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Attention-deficit/hyperactivity disorder, the most prevalent developmental disorder in childhood, is a biologically heterogenous condition characterized by impaired attention and impulse control as well as motoric hyperactivity and anomalous motor skill development. Neuropsychological testing often demonstrates impairments in motivation and reward-related decision making in attention-deficit/hyperactivity disorder, believed to indicate dysfunction of the dopamine reward pathway. Development of reliable, non-invasive, easily obtained and quantitative biomarkers correlating with the presence and severity of clinical symptoms and impaired domains of function could aid in identifying meaningful attention-deficit/hyperactivity disorder subgroups and targeting appropriate treatments.

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Objective: Compared to typically developing (TD) peers, children with attention deficit hyperactivity disorder (ADHD) manifest reduced short interval cortical inhibition (SICI) in the dominant motor cortex measured with transcranial magnetic stimulation (TMS). This multimodal study investigates the inhibitory neurophysiology and neurochemistry by evaluating the relationship between SICI and γ-amino butyric acid (GABA+) levels, measured with magnetic resonance spectroscopy (MRS).

Methods: Across two sites, 37 children with ADHD and 45 TD children, ages 8-12 years, participated.

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Tics are unique from most movement disorders, in that they are partially suppressible. As part of the inhibitory motor network, the pre-supplementary motor area is engaged in motor control and may be involved in tic physiology. We used dual-site transcranial magnetic stimulation to assess inhibitory connectivity between right pre-supplementary motor area and left primary motor cortex, which has previously been demonstrated in healthy adults.

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Functional impairment is an important factor in Tic Disorder treatment decisions. We evaluated the mini Child Tourette Syndrome Impairment Scale (mini-CTIM) for correlation with symptom severity and association with interventions. A total of 61 randomly selected tic encounters were retrospectively analyzed for mini-CTIM correlation with symptom severity scores and compared between patients who received treatment and those who did not.

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Objective: Compared to typically developing (TD) peers, children with attention-deficit/hyperactivity disorder (ADHD) consistently demonstrate impaired transcranial magnetic stimulation (TMS)-evoked short interval cortical inhibition (SICI) of motor evoked potentials (MEPs) in resting motor cortex (M1). To determine whether perturbed M1 physiology also reflects clinically relevant behavioral dysfunction, we evaluated M1 physiology during a cognitive control task taxing motor response selection/inhibition.

Methods: In this case-control study, behavioral ratings, motor skill (assessed using standardized examination), and left M1 physiology were evaluated in 131 right-handed, 8- to 12-year-old children (66 ADHD: mean 10.

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We describe the development of a reproducible, child-friendly motor response inhibition task suitable for online Transcranial Magnetic Stimulation (TMS) characterization of primary motor cortex (M1) excitability and inhibition. Motor response inhibition prevents unwanted actions and is abnormal in several neuropsychiatric conditions. TMS is a non-invasive technology that can quantify M1 excitability and inhibition using single- and paired-pulse protocols and can be precisely timed to study cortical physiology with high temporal resolution.

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Fourteen healthy children (13.8 ± 2.2 years, range 10-16; M:F = 5:9) received 30 Hz intermittent theta burst transcranial magnetic stimulation (iTBS) with a stimulation intensity of 70% of resting motor threshold (RMT) with a total of 300 (iTBS300) pulses.

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Background: Although single- and paired-pulse (sp/pp) transcranial magnetic stimulation (TMS) studies are considered minimal risk in adults and children, the safety profile for theta-burst TMS (TBS) is unknown.

Objective: In this comparative analysis, we explored the rate, severity, and specific symptoms of TMS-related adverse effects (AEs) between sp/ppTMS and TBS in subjects between ages 6 and 18 years.

Method: Data from 165 participants from 2009 to 2014 were analyzed.

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Clinical trials in children with attention-deficit hyperactivity disorder (ADHD) show variability in behavioral responses to the selective norepinephrine reuptake inhibitor atomoxetine. The objective of this study was to determine whether transcranial magnetic stimulation-evoked short interval cortical inhibition might be a biomarker predicting, or correlating with, clinical atomoxetine response. At baseline and after 4 weeks of atomoxetine treatment in 7- to 12-year-old children with ADHD, transcranial magnetic stimulation short interval cortical inhibition was measured, blinded to clinical improvement.

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Background: Open label studies have shown repetitive transcranial magnetic stimulation to be effective in reducing tics.

Objectives: To determine whether 8 sessions of continuous theta burst stimulation (cTBS) over supplementary motor area (SMA) given over 2 days may reduce tics and motor cortical network activity in Tourette syndrome/chronic tic disorders.

Methods: This was a randomized (1:1), double-blind, sham-controlled trial of functional MRI (fMRI)-navigated, 30 Hz cTBS at 90% of resting motor threshold (RMT) over SMA in 12 patients ages 10-22 years.

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Children affected by attention-deficit/hyperactivity disorder demonstrate diminished intrahemispheric inhibition (short interval cortical inhibition), as measured by transcranial magnetic stimulation. This study determined whether interhemispheric inhibition (ipsilateral silent period latency) correlates with clinical behavioral rating and motor control deficits of affected children. In 114 right-handed children (aged 8-12 years; age/sex-matched; 50 affected, 64 controls), we performed comprehensive assessments of behavior, motor skills, and cognition.

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Theta Burst Stimulation (TBS) is a relatively new form of repetitive Transcranial Magnetic Stimulation (TMS) used to probe neuroplasticity in the human cortex. Thirty-Hz TBS, a variation of the originally described 50Hz TBS, has been shown to induce cortical changes in several nonmotor regions. However, its effects over the primary motor cortex have not been examined.

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Aim: Theta-burst stimulation (TBS) is a lower intensity, high-frequency repetitive transcranial magnetic stimulation technique developed recently for quantifying and modulating cerebral cortical function. Nearly all published studies have involved adults. The aim of this study was to obtain safety data as a basis for evaluating potential risks versus benefits of TBS research in children.

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