Preterm birth is associated with dystonic features and reduced cortical parvalbumin immunoreactivity in mice.

BACKGROUND: Preterm birth is a common cause of dystonia. Though dystonia is often associated with striatal dysfunction after neonatal brain injury, cortical dysfunction may best predict dystonia following preterm birth. Furthermore, abnormal sensorimotor cortex inhibition is associated with genetic and idiopathic dystonias. To investigate cortical dysfunction and dystonia following preterm birth, we developed a new model of preterm birth in mice. METHODS: We induced preterm birth in C57BL/6J mice at embryonic day 18.3, ~24 h early. Leg adduction variability and amplitude, metrics we have shown distinguish between dystonia from spasticity during gait in people with CP, were quantified from gait videos of mice. Parvalbumin-positive interneurons, the largest population of cortical inhibitory interneurons, were quantified in the sensorimotor cortex and striatum. RESULTS: Mice born preterm demonstrate increased leg adduction amplitude and variability during gait, suggestive of clinically observed dystonic gait features. Mice born preterm also demonstrate fewer parvalbumin-positive interneurons and reduced parvalbumin immunoreactivity in the sensorimotor cortex, but not the striatum, suggesting dysfunction of cortical inhibition. CONCLUSIONS: These data may suggest an association between cortical dysfunction and dystonic gait features following preterm birth. We propose that our novel mouse model of preterm birth can be used to study this association. IMPACT: Mouse models of true preterm birth are valuable for studying clinical complications of prematurity. Mice born preterm demonstrate increased leg adduction amplitude and variability during gait, suggestive of clinically observed dystonic gait features. Mice born preterm demonstrate fewer parvalbumin-positive interneurons and reduced parvalbumin immunoreactivity in the sensorimotor cortex, suggesting dysfunction of cortical inhibition. Mice born preterm do not demonstrate changes in parvalbumin immunoreactivity in the striatum. Cortical dysfunction may be associated with dystonic gait features following preterm birth.

Dystonia in individuals with spastic cerebral palsy and isolated periventricular leukomalacia.

AIM: To determine the prevalence of dystonia in individuals with periventricular leukomalacia (PVL) and spastic cerebral palsy (CP), but without basal ganglia and thalamic injury (BGTI) on brain magnetic resonance imaging (MRI). METHOD: This was a retrospective study of individuals with spastic CP and PVL on MRI evaluated between 2005 and 2018 in a CP center. Individuals with non-PVL brain lesions on MRI, including BGTI, were excluded. Dystonia was assessed via blinded review of neurological exam videos by pediatric movement disorders specialists. RESULTS: Eighty-five participants (45 males, 40 females; mean age at videotaping 12 years [standard deviation 5 years 6 months], range 4-26 years) met inclusion and exclusion criteria. Of these participants, 50 (59%) displayed dystonia in their exam videos. The most common locations of dystonia were the fingers and hip adductors. The prevalence of dystonia was unaffected by the gestational age or severity of PVL, and was affected by Gross Motor Function Classification System level. INTERPRETATION: Dystonia is common in individuals with spastic CP and PVL, even without BGTI on MRI. Our findings suggest vigilance for dystonia in individuals with spastic CP should remain high, even without MRI evidence of BGTI. WHAT THIS PAPER ADDS: Individuals with spastic cerebral palsy and isolated periventricular leukomalacia on magnetic resonance imaging commonly display dystonia. Common sites of dystonia are in the fingers and hip adductors.

Determinants of gait dystonia severity in cerebral palsy.

AIM: To determine the movement features governing expert assessment of gait dystonia severity in individuals with cerebral palsy (CP). METHOD: In this prospective cohort study, three movement disorder neurologists graded lower extremity dystonia severity in gait videos of individuals with CP using a 10-point Likert-like scale. Using conventional content analysis, we determined the features experts cited when grading dystonia severity. Then, using open-source pose estimation techniques, we determined gait variable analogs of these expert-cited features correlating with their assessments of dystonia severity. RESULTS: Experts assessed videos from 116 participants (46 with dystonia aged 15 years [SD 3] and 70 without dystonia aged 15 years [SD 2], both groups ranging 10-20 years old and 50% male). Variable limb adduction was most commonly cited by experts when identifying dystonia, comprising 60% of expert statements. Effect on gait (regularity, stability, trajectory, speed) and dystonia amplitude were common features experts used to determine dystonia severity, comprising 19% and 13% of statements respectively. Gait variables assessing adduction variability and amplitude (inter-ankle distance variance and foot adduction amplitude) were significantly correlated with expert assessment of dystonia severity (multiple linear regression, p < 0.001). INTERPRETATION: Adduction variability and amplitude are quantifiable gait features that correlate with expert-determined gait dystonia severity in individuals with CP. Consideration of these features could help optimize and standardize the clinical assessment of gait dystonia severity in individuals with CP.

Adults with Cerebral Palsy Require Ongoing Neurologic Care: A Systematic Review.

Cerebral palsy (CP) neurologic care and research efforts typically focus on children. However, most people with CP are adults. Adults with CP are at increased risk of new neurologic conditions, such as stroke and myelopathy, that require ongoing neurologic surveillance to distinguish them from baseline motor impairments. Neurologic factors could also contribute to the motor function decline, chronic pain, and chronic fatigue that are commonly experienced by adults with CP. Based on a systematic literature review, we suggest (1) guidelines for neurologic surveillance and neurologist referral and (2) clinical research questions regarding the evolving neurologic risks for adults with CP. ANN NEUROL 2021;89:860-871.

Diagnostic preferences include discussion of etiology for adults with cerebral palsy and their caregivers.

AIM: To determine the views of individuals with cerebral palsy (CP) and their caregivers (CP community members) about carrying a CP diagnosis, an etiological diagnosis, or both diagnoses together. METHOD: We surveyed CP community members across two registries querying their views on carrying a CP diagnosis, one type of etiological diagnosis (specifically, a genetic diagnosis), or both. Open-ended responses were analyzed using a conventional content analysis approach. RESULTS: Of 197 respondents (108 adults with CP and 89 caregivers), most (75%) valued knowing the cause of their CP. Of those with a diagnostic preference, most preferred carrying both CP and etiological diagnoses together (68%). When compared with carrying an etiological diagnosis alone, significantly more respondents felt a CP diagnosis helped anticipate symptom evolution (84% vs 54%), explain symptoms to others (86% vs 48%), access services (86% vs 48%), and join support communities (78% vs 50%) (p <  0.01, χ2 test). INTERPRETATION: Most CP community members surveyed want to know the cause of their CP and would prefer carrying both CP and etiological diagnoses together. Clinical practice should evolve to meet these community needs.

Gait features of dystonia in cerebral palsy.

AIM: To determine the features cited by motor phenotyping experts when identifying dystonia in people with cerebral palsy (CP). METHOD: Dystonia identification in CP, particularly when comorbid with spasticity, can be difficult. The dystonia diagnostic criterion standard remains subjective visual identification by expert consensus. For this qualitative study, we conducted an inductive thematic analysis of consensus-building discussions between three pediatric movement disorder physicians as they identified the presence or absence of dystonia in gait videos of 40 participants with spastic CP and periventricular leukomalacia. RESULTS: Unanimous consensus about the presence or absence of dystonia was achieved for 34 out of 40 videos. Two main themes were present during consensus-building discussions as videos were evaluated for dystonia: (1) unilateral leg or foot adduction that was variable over time, and (2) difficulty in identifying dystonia. Codes contributing to the first theme were more likely to be cited by a discussant when they felt dystonia was present (as opposed to absent) in a video (χ2 test, p=0.004). DISCUSSION: These results describe the gait features cited by experts during consensus-building discussion as they identify dystonia in ambulatory people with CP. Qualitative thematic analysis of these discussions could help codify the subjective process of dystonia diagnosis.

Striatal cholinergic interneuron numbers are increased in a rodent model of dystonic cerebral palsy.

Neonatal brain injury leading to cerebral palsy (CP) is the most common cause of childhood dystonia, a painful and functionally debilitating movement disorder. Rare monogenic etiologies of dystonia have been associated with striatal cholinergic interneuron (ChI) pathology. However it is unclear whether striatal ChI pathology is also associated with dystonia following neonatal brain injury. We used unbiased stereology to estimate striatal ChI and parvalbumin-positive GABAergic interneuron (PVI) numbers in a rodent model of neonatal brain injury that demonstrates electrophysiological markers of dystonia and spasticity. Striatal ChI numbers are increased following neonatal brain injury while PVI numbers are unchanged. These numbers do not correlate with electrophysiologic measures of dystonia severity. This suggests that striatal ChI pathology, though present, may not be the primary pathophysiologic contributor to dystonia following neonatal brain injury. Increased striatal ChI numbers could instead represent a passenger or protective phenomenon in the setting of dystonic CP.

Sex may influence motor phenotype in a novel rodent model of cerebral palsy.

Cerebral palsy (CP) is the most common cause of childhood motor disability, manifesting most often as spasticity and/or dystonia. Spasticity and dystonia are often co-morbid clinically following severe injury at term gestation. Currently available animal CP models have not demonstrated or differentiated between these two motor phenotypes, limiting their clinical relevance. We sought to develop an animal CP model displaying objectively identifiable spasticity and dystonia. We exposed rat pups at post-natal day 7-8 (equivalent to human 37 post-conceptional weeks) to global hypoxia. Since spasticity and dystonia can be difficult to differentiate from each other in CP, objective electrophysiologic markers of motor phenotypes were assessed. Spasticity was inferred using an electrophysiologic measure of hyperreflexia: soleus Hoffman reflex suppression with 2 Hz tibial nerve stimulation. Dystonia was assessed during voluntary isometric hindlimb withdrawal at different levels of arousal by calculating tibialis anterior and triceps surae electromyographic co-activation as a surrogate of overflow muscle activity. Hypoxia affected spasticity and dystonia measures in a sex-dependent manner. Males had attenuated Hoffman reflex suppression suggestive of spasticity but no change in antagonist muscle co-activation. In contrast, females demonstrated increased co-activation suggestive of dystonia but no change in Hoffman reflex suppression. Therefore, there was an unexpected segregation of electrophysiologically-defined motor phenotypes based on sex with males predominantly demonstrating spasticity and females predominantly demonstrating dystonia. These results require human clinical confirmation but suggest that sex could play a critical role in the motor manifestations of neonatal brain injury.

Treatable Movement Disorders of Infancy and Early Childhood.

Movement disorders in childhood can be difficult to diagnose early. Disease processes present variably and can mimic each other. It is particularly important to remain vigilant for the subset of these movement disorders that are treatable. These disorders can be managed with (1) treatments specific to the disease that substantially reduce symptoms; (2) treatments that can prevent progression; (3) treatments that can hasten recovery; or (4) surveillance and management of the associated, sometimes life-threatening, comorbidities. Here, we present a practical and phenomenology-oriented framework for diagnosing and managing these treatable movement disorders of infancy and early childhood.

Deep brain stimulation for monogenic dystonia.

PURPOSE OF REVIEW: Deep brain stimulation (DBS) has recently emerged as an important management option in children with medically refractory dystonia. DBS is most commonly used, best studied, and thought to be most efficacious for a select group of childhood or adolescent onset monogenic dystonias (designated with a standard 'DYT' prefix). We review how to clinically recognize these types of dystonia and the relative efficacy of DBS for key monogenic dystonias. RECENT FINDINGS: Though used for dystonia in adults for several years, DBS has only lately been used in children. Recent evidence shows that patients with shorter duration of dystonia often experience greater benefit following DBS. This suggests that early recognition of the appropriate dystonic phenotypes and consideration of DBS in these patients may improve the management of dystonia. SUMMARY: DBS should be considered early in patients who have medically refractory dystonia, especially for the monogenic dystonias that have a high response rate to DBS. It is important to differentiate between these monogenic dystonias and dystonias of other causes to properly prognosticate for these patients and to determine whether DBS is an appropriate management option.

Factors Associated With Discharge After Initial Emergency Treatment of Pediatric Migraine.

OBJECTIVE: Migraine treatment varies widely in the pediatric emergency department (ED). Factors associated with discharge after only initial emergency treatment were examined. METHODS: A retrospective chart analysis was conducted on patients 6 to 18 years old who presented to the St. Louis Children's Hospital ED between January 1, 2008, and December 31, 2011, with a discharge diagnosis of migraine (n = 700 visits). Associations between patient characteristics, initial treatments, and rates of discharge after only initial treatment were examined using a generalized linear model and receiver operating characteristic curves. RESULTS: If exclusively oral or intranasal (PO/IN) medications were given initially (n = 285), ibuprofen alone was associated with lower discharge rates compared with other PO/IN medication regimens (P < 0.05). The only other variable associated with discharge was arrival pain score (P < 0.05). When ibuprofen alone was administered, pain scores equal to or lower than 5/10 were associated with the greatest sensitivity and specificity for discharge. With administration of other PO/IN regimens, pain scores equal to or lower than 8/10 were associated with the greatest sensitivity and specificity for discharge. If intravenous (IV) medications were given initially (n = 415), ketorolac given with an antinausea medication was associated with higher discharge rates compared with independent administration of these medications (P < 0.05). Intravenous medications were associated with higher discharge rates compared with PO/IN medications (P < 0.001). CONCLUSIONS: Arrival pain score may be used to help select initial migraine treatment in the pediatric ED. Initial use of PO/IN regimens including triptans or an antiemetic and concurrent administration of IV ketorolac with an antiemetic may be associated with higher rates of discharge after initial treatment alone.

Long-term increase in coherence between the basal ganglia and motor cortex after asphyxial cardiac arrest and resuscitation in developing rats.

BACKGROUND: The basal ganglia are vulnerable to injury during cardiac arrest. Movement disorders are a common morbidity in survivors. Yet, neuronal motor network changes post-arrest remain poorly understood. METHODS: We compared function of the motor network in adult rats that, during postnatal week 3, underwent 9.5 min of asphyxial cardiac arrest (n = 9) or sham intervention (n = 8). Six months after injury, we simultaneously recorded local field potentials (LFP) from the primary motor cortex (MCx) and single neuron firing and LFP from the rat entopeduncular nucleus (EPN), which corresponds to the primate globus pallidus pars interna. Data were analyzed for firing rates, power, and coherence between MCx and EPN spike and LFP activity. RESULTS: Cardiac arrest survivors display chronic motor deficits. EPN firing rate is lower in cardiac arrest survivors (19.5 ± 2.4 Hz) compared with controls (27.4 ± 2.7 Hz; P < 0.05). Cardiac arrest survivors also demonstrate greater coherence between EPN single neurons and MCx LFP (3-100 Hz; P < 0.001). CONCLUSIONS: This increased coherence indicates abnormal synchrony in the neuronal motor network after cardiac arrest. Increased motor network synchrony is thought to be antikinetic in primary movement disorders. Characterization of motor network synchrony after cardiac arrest may help guide management of post-hypoxic movement disorders.

Mice born preterm develop gait dystonia and reduced cortical parvalbumin immunoreactivity.

Preterm birth leading to cerebral palsy (CP) is the most common cause of childhood dystonia, a movement disorder that is debilitating and often treatment refractory. Dystonia has been typically associated with dysfunction of striatal cholinergic interneurons, but clinical imaging data suggests that cortical injury may best predict dystonia following preterm birth. Furthermore, abnormal sensorimotor cortex inhibition has been found in many studies of non-CP dystonias. To assess the potential for a cortical etiology of dystonia following preterm birth, we developed a new model of preterm birth in mice. Noting that term delivery in mice on a C57BL/6J background is embryonic day 19.1 (E19.1), we induced preterm birth at the limits of pup viability at embryonic day (E) 18.3, equivalent to human 22 weeks gestation. Mice born preterm demonstrate display clinically validated metrics of dystonia during gait (leg adduction amplitude and variability) and also demonstrate reduced parvalbumin immunoreactivity in the sensorimotor cortex, suggesting dysfunction of cortical parvalbumin-positive inhibitory interneurons. Notably, reduced parvalbumin immunoreactivity or changes in parvalbumin-positive neuronal number were not observed in the striatum. These data support the association between cortical dysfunction and dystonia following preterm birth. We propose that our mouse model of preterm birth can be used to study this association and potentially also study other sequelae of extreme prematurity.

Uncertainties Regarding Cerebral Palsy Diagnosis: Opportunities to Clarify the Consensus Definition.

Background and Objectives: We have established that physicians, including neurologists, variably diagnose cerebral palsy (CP) when using the most recent CP definition from 2006. We also know that child neurologists and neurodevelopmentalists view themselves to be optimally suited to diagnose CP based on their training backgrounds. Therefore, to reduce variability in CP diagnosis, our objective was to elucidate uncertainties child neurologists and neurodevelopmentalists may have regarding practical application of the 2006 definition. Methods: We conducted a cross-sectional survey of child neurologists and neurodevelopmentalists built into a discussion seminar at the 2022 Child Neurology Society (CNS) Annual Meeting, the largest professional meeting of these specialists in North America. Seminar attendees were provided the 2006 definition and asked whether they had any uncertainties about the practical application of the definition across 4 hypothetical clinical vignettes. A group of national and international CP leaders then processed these data through iterative discussions to develop recommendations for clarifying the 2006 definition. Results: The seminar was attended by 50% of all conference attendees claiming CME (202/401). Of the 164 closing survey respondents, 145 (88%) expressed uncertainty regarding the clinical application of the 2006 definition. These uncertainties focused on 1) age, both regarding the minimum and maximum ages of brain disturbance or motor symptom onset (67/164, 41%), and 2) interpretation of the term "nonprogressive" (48/164, 29%). Almost all respondents (157/164, 96%) felt that we should revise the 2006 consensus definition of CP. Discussion: To address the most common CP diagnostic uncertainties we identified, we collectively propose 4 points of clarification to the 2006 definition: 1) motor symptoms/signs should be present by 2 years old; 2) CP can and should be diagnosed as early as possible; 3) the clinical motor disability phenotype should be nonprogressive through 5 years old; and 4) a CP diagnosis should be re-evaluated if motor disability is progressive or absent by 5 years old. We anticipate that clarifying the 2006 definition of CP in this manner could address the uncertainties we identified among child neurologists and neurodevelopmentalists and reduce the diagnostic variability that currently exists.

Analysis of Gender Discrepancies in Leadership Roles and Recognition Awards in the Child Neurology Society.

BACKGROUND AND OBJECTIVES: Gender disparities have been demonstrated across several medical specialties, including neurology. Although women have comprised most of the child neurology trainees since 2007, it is not apparent whether this demographic shift is reflected in the Child Neurology Society (CNS) awards and leadership. This study aimed to evaluate the differences in gender representation among leadership positions and award recipients within the CNS. The primary outcome measure was the total number of board of director (BOD) positions or awards given by gender each year. METHODS: A retrospective review of publicly available data was conducted on CNS members, post-training award recipients, and BOD positions, including nomination records, from 1972 to 2023. Data abstracted were restricted to gender to preserve member and nominee anonymity. Gender identification and consensus were determined through a combination of strategies and study members. Data analysis included descriptive statistics, Pearson χ2 test, and the exact binomial test to compare gender proportions and the probability of being underrepresented in awards, leadership, and nominations over time. Data are presented according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. RESULTS: From 1972 to 2023, women represented 29% (44/152) of the BOD positions and 26% (61/236) of post-training award recipients presented by the CNS. Despite the increase in the proportion of women in child neurology, the overall gap in gender representation in leadership positions remains broadly stable. Only 13% (4/32) of CNS presidents have been women, a significant underrepresentation (95% CI 2.3%-52%, p < 0.004), although the representation of women in nonpresidential positions increased from 2003 to 2023. Women are also underrepresented as overall awardees (95% CI 12%-38%, p < 0.00001) except for the Philip R. Dodge Young Investigator Award, which is an investigator-initiated application. DISCUSSION: Women remain underrepresented at the highest levels of recognition in child neurology despite representing most of the field. Reasons for disparities are known to be multifactorial and likely include gender bias and structural sexism. We present several discussion topics that seek to rationalize this disparity and provide suggestions for improving diversity, equity, and inclusion for leadership roles and awards.

Multi-center improvement in screening for dystonia in young people with cerebral palsy.

Background and Objectives: Dystonia is a common, debilitating, and often treatment refractory motor symptom of cerebral palsy (CP), affecting 70-80% of this population based on research assessments. However, routine clinical evaluation for dystonia in CP has failed to match these expected numbers. Addressing this diagnostic gap is a medical imperative because the presence of dystonia rules in or out certain treatments for motor symptoms in CP. Therefore, our objective was to optimize rates of clinical dystonia screening to improve rates of clinical dystonia diagnosis. Methods: Using the quality improvement (QI) infrastructure of the Cerebral Palsy Research Network (CPRN), we developed and implemented interventions to increase the documentation percentage of five features of dystonia in young people with CP, aged 3-21 years old. This QI initiative was implemented by seven physiatry and pediatric movement disorders physicians at four tertiary-care pediatric hospitals between 10/10/21 and 7/1/23. We collected visit data cross-sectionally across all participating sites every 2 weeks and tracked our progress using control charts. Results: We assessed 847 unique visits, mostly for established patients (719/847, 85%) who were 9.2 years old on average (95% CI 8.8-9.5). By 4/10/22, the mean percentage of dystonia screening elements documented across all sites rose from 39% to 90% and the mean percentage of visits explicitly documenting the presence or absence of dystonia rose from 65% to 94%. By 10/23/22, the percentage of visits diagnosing dystonia rose from 57% to 74%. These increases were all sustained through the end of the study period in 7/1/23. Discussion: Using a rigorous QI-driven process across four member sites of a North American learning health network (CPRN), we demonstrated that we could increase screening for dystonia and that this was associated with increased clinical dystonia diagnosis, matching expected research-based rates. We propose that similar screening should take place across all sites caring for people with CP.

Current Practices in the Evaluation of Global Developmental Delay/Intellectual Disability: A Nationwide Survey of Child Neurologists.

Background and Objectives: Global developmental delay/intellectual disability (GDD/ID) are among the most common neurologic conditions evaluated by child neurologists in the United States. No recent neurology-specific guidelines for GDD/ID diagnostic evaluation exist, which could lead to practice variability. We assessed current practices in GDD/ID diagnostic evaluation among US child neurologists, including drivers of exome sequencing (ES). Methods: A 19-item online anonymous survey was distributed between April 2021 and September 2021 to 953 eligible child neurologists by email and/or online platforms through the American Academy of Neurology and Child Neurology Society. Multinomial logistic regression was used to determine the predictors of sending ES as a part of GDD/ID diagnostic evaluation. Results: Of 172 unique respondents, 69.2% reported almost always obtaining a chromosomal microarray while 10.5% reported almost always pursuing ES. However, 65.1% identified ES as a first-tier diagnostic test for GDD/ID. Clinical practice demographics independently associated with a higher likelihood of pursuit of ES were more years of experience (p = 0.002) and more people with GDD/ID in one's practice (p < 0.001). Inclusion of brain MRI, EEG, and metabolic laboratory values as part of GDD/ID diagnostic evaluation varied widely. Modalities to screen for treatable disorders (ES or metabolic laboratory values) were reported to be consistently used by only 24.8% of respondents. Respondents identified key barriers to the pursuit of ES including the need for genetics referral/genetic counseling and insurance coverage/out-of-pocket cost. Discussion: Among US child neurologists, there is marked practice variability in GDD/ID diagnostic evaluation across multiple types of testing, raising concern for disparities in care. There is a widespread lack of screening for treatable causes of ID, which may lead to missed diagnoses and avoidable morbidity. Despite most respondents' support for ES as a first-tier diagnostic test for GDD/ID, only a small minority routinely pursue ES as a part of their evaluation. Provider-level factors (years of experience, percent of patients with GDD/ID) and system-level barriers (access to genetics expertise, lack of insurance coverage) were determinants of the frequency of use of ES. These findings suggest the need for updated consensus guidelines and advocacy/education to improve child neurologists' ability to pursue ES for GDD/ID.

Spared nerve injury causes motor phenotypes unrelated to pain in mice.

Most animal models of neuropathic pain use targeted nerve injuries quantified with motor reflexive measures in response to an applied noxious stimulus. These motor reflexive measures can only accurately represent a pain response if motor function in also intact. The commonly used spared nerve injury (SNI) model, however, damages the tibial and common peroneal nerves that should result in motor phenotypes (i.e., an immobile or "flail" foot) not typically captured in sensory assays. To test the extent of these issues, we used DeepLabCut, a deep learning-based markerless pose estimation tool to quantify spontaneous limb position in C57BL/6J mice during tail suspension following either SNI or sham surgery. Using this granular detail, we identified the expected flail foot-like impairment, but we also found SNI mice hold their injured limb closer to the body midline compared to shams. These phenotypes were not present in the Complete Freunds Adjuvant model of inflammatory pain and were not reversed by multiple analgesics with different mechanisms of action, suggesting these SNI-specific phenotypes are not directly related to pain. Together these results suggest SNI causes previously undescribed phenotypes unrelated to altered sensation that are likely underappreciated while interpreting preclinical pain research outcomes.

Brain Region Size Differences Associated With Dystonia in People With Cerebral Palsy Born Premature.

BACKGROUND: Dystonia in cerebral palsy (CP) is classically associated with deep gray matter injury at term gestation, but the patterns of injury associated with dystonia following premature birth are unclear. We examined whether there were brain regional size differences associated with dystonia in people with CP born premature. METHODS: In this retrospective cohort study, we identified subjects with CP born premature (<37 weeks gestational age) seen at a tertiary care CP center between February 1, 2017, to February 1, 2021, who had T1-weighted brain magnetic resonance imaging (MRI) done between ages one and five years available in the clinical record. We measured the following on these brain MRI images per the 2013 Kidokoro criteria: interhemispheric distance, biparietal width, lateral ventricle diameter, transcerebellar diameter, deep gray matter area, and corpus callosum thickness. We then compared the sizes of these structures between those with and without dystonia correcting for gestational age at birth and gross motor functional ability (univariate general linear models). RESULTS: Fifty-five subjects met the inclusion and exclusion criteria. Interhemispheric distance was significantly greater in those with dystonia, suggesting decreased cortical volume (P = 0.005). There was no significant difference in the other measured structures between those with and without dystonia, including deep gray matter area. CONCLUSIONS: Increased interhemispheric distance, not measures of deep gray matter size, correlate with the presence of dystonia in people with CP born premature.

Upper Extremity Dystonia Features in People With Spastic Cerebral Palsy.

Background and Objectives: Dystonia in cerebral palsy (CP) is debilitating and common, but underdiagnosed, especially when coexistent with spasticity. With dedicated research-based assessment, dystonia is found in most people with spastic CP but is only clinically diagnosed in the minority. To begin addressing the high rates of dystonia underdiagnosis in this population, we determined the key feature experts use to assess upper extremity dystonia in people with spastic CP. Methods: In this prospective cohort study, 3 pediatric movement disorder specialists assessed upper extremity dystonia in neurologic examination videos of people with spastic CP and isolated periventricular leukomalacia (PVL) on brain MRI (i.e., those with a brain injury pattern typical for spastic CP). Dystonia severity was rated using the 10-point Global Dystonia Severity Rating Scale, first by each expert independently and then again after consensus-building discussion. Conventional content analysis of these discussions revealed salient features ("codes") that experts used to assess upper extremity dystonia. Code frequency distributions were compared between dystonia severity categories using χ2 tests. Results: We identified 96 people with spastic CP with isolated PVL on brain MRI seen in the St. Louis Children's Hospital CP Center between 2005 and 2018. Of them, 26 people were able and willing to be recorded while doing a standardized set of upper extremity examination maneuvers (age 4-25 years; 28% nonambulatory, 77% White). When assessing their videos, experts cited the "hand" less often and "shoulder" more often with increasing dystonia severity (p < 0.005, χ2 test). "Mirror movements" and the "hand open/close" examination maneuver were cited significantly more frequently in videos when experts were attempting to distinguish between no dystonia and mild dystonia (p < 0.005). Discussion: Expert clinicians use distinct movement features to assess upper extremity dystonia in people with spastic CP and PVL. Attention to involuntary shoulder (vs hand) movements can help gauge dystonia severity. Differentiation between mirror movements and dystonia, particularly during the hand open/close examination maneuver, may help identify mild dystonia. These results can help guide upper extremity dystonia assessment in people with spastic CP, thus potentially helping mitigate dystonia underdiagnosis.