From urges to tics in children with Tourette syndrome: associations with supplementary motor area GABA and right motor cortex physiology.

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. To determine whether cortical physiological properties correlate with urges and tics, we evaluated, in 8-12-year-old right-handed TS children (n = 17), correlations of urge and tic severity scores and compared both to cortical excitability (CE) and short- and long-interval cortical inhibition (SICI and LICI) in both left and right M1. We also modeled these M1 transcranial magnetic stimulation measures with SMA gamma-amino butyric acid (GABA) levels in TS and typically developing control children (n = 16). Urge intensity correlated strongly with tic scores. More severe urges correlated with lower CE and less LICI in both right and left M1. Unexpectedly, in right M1, lower CE and less LICI correlated with less severe tics. We found that SMA GABA modulation of right, but not left, M1 CE and LICI differed in TS. We conclude that in young children with TS, lower right M1 CE and LICI, modulated by SMA GABA, may reflect compensatory mechanisms to diminish tics in response to premonitory urges.

Adult Neurology Rotations for Child Neurology Residents: Exploring the Resident Perspective.

BACKGROUND: In 2014 the Accreditation Council for Graduate Medical Education modified adult training requirements for child neurology certification to reduce the number of hospital-based rotations and require inclusion of outpatient clinic and electives. We aimed to identify how these training requirements are being met and explored its impact on residents. METHODS: A REDCap questionnaire surveying resident opinion on impact of adult training on resident education, professional development, and wellness was e-mailed to 79 program directors in the United States for distribution in 2020. Results were analyzed using descriptive statistics and t test calculations. Qualitative analysis of narrative responses involved theme identification. RESULTS: A total of 116 child neurology residents participated (30.2% PGY-3, 37.9% PGY-4, and 31.9% PGY-5 residents); 20.9% had all adult rotations during the PGY-3 year, and 79.1% had adult rotations spread throughout residency. Adult training had a small positive impact on resident autonomy and a negative impact on resident wellness regardless of training structure. However, residents with 12 months of adult training during PGY-3 year scored worse on burnout, mood changes, work-life balance, and social well-being (P < 0.05). Some themes identified included residents feeling unsafe due to lack of supervision, that education was not prioritized, and that adult patient care lacked relevance to long-term career goals. CONCLUSIONS: Adult neurology training was found to negatively affect child neurology resident wellness, with a larger negative impact when adult training was completed in 12 months during PGY-3 year. Other identified areas where change could be implemented include improving feelings of resident safety and prioritizing quality and relevance of education.

Adult Neurology Rotations for Child Neurology Residents: A Survey of Program Directors.

BACKGROUND AND OBJECTIVES: We aimed to identify how child neurology and neurodevelopmental disabilities residency program directors (PDs) implemented revised Accreditation Council for Graduate Medical Education requirements for adult neurology training for child neurology residents. Before 2014, the American Board of Psychiatry and Neurology certification for child neurology required an adult year, with no specified rotation requirements. At that point, programs scheduled a median of 10 months of adult neurology rotations during the third postgraduate year (PGY-3). In 2014, the adult neurology requirements were modified to include 6 months of hospital-based, 3 months of outpatient, and 3 months of other elective (may include neurophysiology, neuropathology, and/or neuroradiology) rotations. However, the effects of these changes on child neurology residency training nationally have not been characterized. METHODS: A 16-item online survey was emailed to 79 PDs in the United States in September 2020. Survey responses were collected from September to October 2020. Descriptive statistics were calculated, and associations with departmental affiliation (pediatrics/neurology), graduate medical education (GME) funding source, and program size were compared using nonparametric tests. RESULTS: The response rate was 72% (53 pediatric neurology, 3 neurodevelopmental disabilities). The median adult months per year of training were as follows: 9 PGY-3, 2 PGY-4, and 1 PGY-5. Nearly all had both hospital inpatient and consult rotations with night and/or weekend shifts; 57% included neurocritical care and 36% epilepsy monitoring units. 48% of programs scheduled night and weekend shifts (including 25% that scheduled 24-hour calls) for residents on outpatient and elective rotations. Few programs required adult neurophysiology (20%), neuropathology (32%), or neuroradiology (25%). Programs with children's hospital GME funding (for either 2 or 3 years) tended to be larger (p = 0.008). Otherwise, departmental affiliation, funding source, and program size were not associated with rotation timing. DISCUSSION: Most child neurology residency programs still consolidate adult training in the PGY-3 year and often schedule additional hospital shifts during outpatient and elective months. However, there is a small shift toward adult neurology rotations occurring in the PGY-4 and PGY-5. Departmental affiliation, funding source, and program size do not consistently affect training practices. Few programs mandate adult neurophysiology, neuropathology, or neuroradiology rotations.

EEG Correlates of Active Stopping and Preparation for Stopping in Chronic Tic Disorder.

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. Between-group differences in spectral power changes (3-50 Hz) were explored after source localization and multiple comparisons correction. Two epochs within the stop signal task were studied: (1) preparatory phase early in the trial before motor execution/inhibition and (2) active inhibition phase after stop signal presentation. Correlation analyses between electrophysiologic data and clinical rating scales for tic, obsessive-compulsive symptoms, and inattention/hyperactivity were performed. There were no behavioral or electrophysiological differences during active stopping. During stop preparation, CTD participants showed greater event-related desynchronization (ERD) in the RSFG (γ-band), RMFG (ß, γ-bands), and RIFG (θ, α, ß, γ-bands). Higher RSFG γ-ERD correlated with lower tic severity (r = 0.66, p = 0.04). Our findings suggest RSFG γ-ERD may represent a mechanism that allows CTD patients to keep tics under control and achieve behavioral performance similar to peers.

Altered frontal-mediated inhibition and white matter connectivity in pediatric chronic tic disorders.

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. We also used diffusion tensor imaging to investigate white matter connectivity in children with chronic tics. Twelve children with chronic tic disorder and fourteen typically developing controls underwent MRI with diffusion tensor imaging indices analysis followed by single and paired-pulse transcranial magnetic stimulation with conditioning pulse over the right pre-supplementary motor area followed by left motor cortex test pulse. Neurophysiologic and imaging data relationships to measures of tic severity and suppressibility were also evaluated in tic patients. Pre-supplementary motor area-mediated inhibition of left motor cortex was present in healthy control children but not in chronic tic disorder participants. Less inhibition correlated with worse tic suppressibility (ρ = - 0.73, p = 0.047). Imaging analysis showed increased fractional anisotropy in the right superior longitudinal fasciculus, corpus callosum, corona radiata and posterior limb of the internal capsule (p < 0.05) in tic participants, which correlated with lower self-reported tic suppressibility (ρ = - 0.70, p = 0.05). Physiologic data revealed impaired frontal-mediated motor cortex inhibition in chronic tic participants, and imaging analysis showed abnormalities in motor pathways. Collectively, the neurophysiologic and neuroanatomic data correlate with tic suppressibility, supporting the relevancy to tic pathophysiology.

Implementation of the Mini-Child Tourette Syndrome Impairment Scale: Relationships to Symptom Severity and Treatment Decisions.

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. Regression models identified factors associated with treatment decisions. Mini-CTIM-tic scores correlated with tic severity and mini-CTIM-non-tic scores correlated with attention-deficit hyperactivity disorder (ADHD) severity. Tic treatment was associated with higher child, but not parent, mini-CTIM-tic scores. Regression models identified that comorbidity treatment was predicted by ADHD severity, obsessive compulsive disorder severity, and parent but not child mini-CTIM-non-tic scores. These findings suggest children have valuable insight into their tic-related impairment, but parent assessment is important for evaluating comorbidity-related impairment. The mini-CTIM may be a useful clinical tool for assessing tic-related impairment.