Development of GO Move: A Website for Children With Unilateral Cerebral Palsy

It is unknown if an online tool is wanted by therapists and parents of individuals with unilateral cerebral palsy (UCP) to support implementation of goal-directed home programs, and if wanted, the recommended features for the tool. The objective was to explore the experiences of therapists and parents who have implemented home programs, seek guidance on translating a paper-based home program toolbox into a mobile website, and develop the website. Qualitative descriptive methodology guided data collection using semi-structured interviews and thematic analysis, validated with field notes and member checking. A team science, iterative approach was used to integrate the themes into the development of the mobile website. Five primary themes including recommendations for the functionality, features, content, and naming of the mobile website were identified. Parents and therapists value home programs. Participants provided recommendations regarding content and features, and the GO Move mobile website was developed based on the recommendations.

Characterizing the mechanisms of social connection

Understanding how individuals form and maintain strong social networks has emerged as a significant public health priority as a result of the increased focus on the epidemic of loneliness and the myriad protective benefits conferred by social connection. In this review, we highlight the psychological and neural mechanisms that enable us to connect with others, which in turn help buffer against the consequences of stress and isolation. Central to this process is the experience of rewards derived from positive social interactions, which encourage the sharing of perspectives and preferences that unite individuals. Sharing affective states with others helps us to align our understanding of the world with another's, thereby continuing to reinforce bonds and strengthen relationships. These psychological processes depend on neural systems supporting reward and social cognitive function. Lastly, we also consider limitations associated with pursuing healthy social connections and outline potential avenues of future research.

RAB1A haploinsufficiency phenocopies the 2p14-p15 microdeletion and is associated with impaired neuronal differentiation

Hereditary spastic parapareses (HSPs) are clinically heterogeneous motor neuron diseases with variable age of onset and severity. Although variants in dozens of genes are implicated in HSPs, much of the genetic basis for pediatric-onset HSP remains unexplained. Here, we re-analyzed clinical exome-sequencing data from siblings with HSP of unknown genetic etiology and identified an inherited nonsense mutation (c.523C>T [p.Arg175Ter]) in the highly conserved RAB1A. The mutation is predicted to produce a truncated protein with an intact RAB GTPase domain but without two C-terminal cysteine residues required for proper subcellular protein localization. Additional RAB1A mutations, including two frameshift mutations and a mosaic missense mutation (c.83T>C [p.Leu28Pro]), were identified in three individuals with similar neurodevelopmental presentations. In rescue experiments, production of the full-length, but not the truncated, RAB1a rescued Golgi structure and cell proliferation in Rab1-depleted cells. In contrast, the missense-variant RAB1a disrupted Golgi structure despite intact Rab1 expression, suggesting a dominant-negative function of the mosaic missense mutation. Knock-down of RAB1A in cultured human embryonic stem cell-derived neurons resulted in impaired neuronal arborization. Finally, RAB1A is located within the 2p14-p15 microdeletion syndrome locus. The similar clinical presentations of individuals with RAB1A loss-of-function mutations and the 2p14-p15 microdeletion syndrome implicate loss of RAB1A in the pathogenesis of neurodevelopmental manifestations of this microdeletion syndrome. Our study identifies a RAB1A-related neurocognitive disorder with speech and motor delay, demonstrates an essential role for RAB1a in neuronal differentiation, and implicates RAB1A in the etiology of the neurodevelopmental sequelae associated with the 2p14-p15 microdeletion syndrome.

Social feedback promotes positive social sharing, trust, and closeness

Positive social sharing is an interpersonal emotion regulation strategy that enhances positive affect and social belonging, particularly when met with positive social feedback. Despite the ubiquity of positive social sharing both in person and online, what drives this behavior is not well understood. We hypothesized that positive social feedback serves as a reward that reinforces sharing behavior and strengthens social bonds. Participants made trial-by-trial choices about whether to share social media photos with peers who returned positive ("likes") or negative ("dislikes") feedback. Unbeknownst to participants, peer conditions were manipulated to yield varying amounts of positive and negative feedback. Social bonding was subsequently measured using a trust game and subjective closeness ratings. Participants shared more with peers who provided greater rates of positive feedback. This effect generalized to trust decisions and subjective feelings of closeness and varied individually as a function of interpersonal emotion regulation in daily life. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Control preference persists with age

The opportunity to exert control in one's environment is desirable, and individuals are willing to seek out control, even at a financial cost. Additionally, control-related activation of reward regions in the brain and the positive affect associated with the opportunity to exert control suggest that control is rewarding. The present study explores whether there are age-related differences in the preference for control. Older and younger adults chose whether to maintain control and play a guessing game themselves or to cede this control to the computer. Maintaining and ceding control were associated with different amounts of monetary reward that could be banked upon a successful guess. This required participants to weigh the value associated with control compared to monetary rewards. We found that older adults preferred control and traded monetary reward for control, similar to younger adults. The results suggest that the preference for exerting control may be preserved across age. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Delineation of a novel neurodevelopmental syndrome associated with PAX5 haploinsufficiency

PAX5 is a transcription factor associated with abnormal posterior midbrain and cerebellum development in mice. PAX5 is highly loss-of-function intolerant and missense constrained, and has been identified as a candidate gene for autism spectrum disorder (ASD). We describe 16 individuals from 12 families who carry deletions involving PAX5 and surrounding genes, de novo frameshift variants that are likely to trigger nonsense-mediated mRNA decay, a rare stop-gain variant, or missense variants that affect conserved amino acid residues. Four of these individuals were published previously but without detailed clinical descriptions. All these individuals have been diagnosed with one or more neurodevelopmental phenotypes including delayed developmental milestones (DD), intellectual disability (ID), and/or ASD. Seizures were documented in four individuals. No recurrent patterns of brain magnetic resonance imaging (MRI) findings, structural birth defects, or dysmorphic features were observed. Our findings suggest that PAX5 haploinsufficiency causes a neurodevelopmental disorder whose cardinal features include DD, variable ID, and/or ASD.

Retrospective analysis of a clinical exome sequencing cohort reveals the mutational spectrum and identifies candidate disease-associated loci for BAFopathies

PURPOSE

BRG1/BRM-associated factor (BAF) complex is a chromatin remodeling complex that plays a critical role in gene regulation. Defects in the genes encoding BAF subunits lead to BAFopathies, a group of neurodevelopmental disorders with extensive locus and phenotypic heterogeneity.

METHODS

We retrospectively analyzed data from 16,243 patients referred for clinical exome sequencing (ES) with a focus on the BAF complex. We applied a genotype-first approach, combining predicted genic constraints to propose candidate BAFopathy genes.

RESULTS

We identified 127 patients carrying pathogenic variants, likely pathogenic variants, or de novo variants of unknown clinical significance in 11 known BAFopathy genes. Those include 34 patients molecularly diagnosed using ES reanalysis with new gene-disease evidence (n = 21) or variant reclassifications in known BAFopathy genes (n = 13). We also identified de novo or predicted loss-of-function variants in 4 candidate BAFopathy genes, including ACTL6A, BICRA (implicated in Coffin-Siris syndrome during this study), PBRM1, and SMARCC1.

CONCLUSION

We report the mutational spectrum of BAFopathies in an ES cohort. A genotype-driven and pathway-based reanalysis of ES data identified new evidence for candidate genes involved in BAFopathies. Further mechanistic and phenotypic characterization of additional patients are warranted to confirm their roles in human disease and to delineate their associated phenotypic spectrums.

Muscle Selection and Dosing in a Phase 3, Pivotal Study of AbobotulinumtoxinA Injection in Upper Limb Muscles in Children With Cerebral Palsy

Background: Guidelines recommend botulinum toxin-A in pediatric upper limb spasticity as part of routine practice. Appropriate dosing is a prerequisite for treatment success and it is important that injectors have an understanding on how to tailor dosing within a safe and effective range. We report upper limb dosing data from a phase 3 study of abobotulinumtoxinA injections in children with cerebral palsy.

Methods: This was a double-blind, repeat-treatment study (NCT02106351). In Cycle 1, children were randomized to abobotulinumtoxinA at 2 U/kg control dose or clinically relevant 8 U/kg or 16 U/kg doses. Doses were divided between the primary target muscle group (PTMG, wrist or elbow flexors) and additional muscles tailored to clinical presentation. During Cycles 2–4, children received doses of 8 U/kg or 16 U/kg and investigators could change the PTMG and other muscles to be injected. Injection of muscles in the other upper limb and lower limbs was also permitted in cycles 2–4, with the total body dose not to exceed 30 U/kg or 1,000 U (whichever was lower) in the case of upper and lower limb treatment.

Results: 212 children were randomized, of which 210 received ≥1 abobotulinumtoxinA injection. Per protocol, the elbow and wrist flexors were the most commonly injected upper limb muscles. Across all 4 cycles, the brachialis was injected in 89.5% of children (dose range 0.8–6 U/kg), the brachioradialis in 83.8% (0.4–3 U/kg), the flexor carpi ulnaris in 82.4% (0.5–3 U/kg) and the flexor carpi radialis in 79.5% (0.5–4 U/kg). Other frequently injected upper limb muscles were the pronator teres(70.0%, 0.3–3 U/kg). adductor pollicis (54.3%, 0.3-1 U/kg), pronator quadratus (44.8%, 0.1–2 U/kg), flexor digitorum superficialis (39.0%, 0.5-4 U/kg), flexor digitorum profundus (28.6%, 0.5–2 U), flexor pollicis brevis/opponens pollicis (27.6%, 0.3-1 U/kg) and biceps (27.1%, 0.5–6 U/kg). AbobotulinumtoxinA was well-tolerated at these doses; muscular weakness was reported in 4.3% of children in the 8 U/kg group and 5.7% in the 16 U/kg group.

Conclusions: These data provide information on the pattern of injected muscles and dose ranges used in this study, which were well-tolerated. Per protocol, most children received injections into the elbow and wrist flexors. However, there was a wide variety of other upper limb muscles injected as physicians tailored injection patterns to clinical need.

Finding positive meaning in memories of negative events adaptively updates memory

Finding positive meaning in past negative memories is associated with enhanced mental health. Yet it remains unclear whether it leads to updates in the memory representation itself. Since memory can be labile after retrieval, this leaves the potential for modification whenever its reactivated. Across four experiments, we show that positively reinterpreting negative memories adaptively updates them, leading to the re-emergence of positivity at future retrieval. Focusing on the positive aspects after negative recall leads to enhanced positive emotion and changes in memory content during recollection one week later, remaining even after two months. Consistent with a reactivation-induced reconsolidation account, memory updating occurs only after a reminder and twenty four hours, but not a one hour delay. Multi-session fMRI showed adaptive updates are reflected in greater hippocampal and ventral striatal pattern dissimilarity across retrievals. This research highlights the mechanisms by which updating of maladaptive memories occurs through a positive emotion-focused strategy.

Improved Hand Function in Children With Cerebral Palsy With Repeat Doses of Augmented Pediatric Constraint-Induced Movement Therapy

Date Presented 04/13/21

Children with unilateral cerebral palsy participating in repeat doses of pediatric constraint-induced movement therapy camp augmented with the Hocoma Armeo®Spring demonstrated significant improvements in hand function and bimanual performance for both doses and showed a generalized upward trend in hand function over time.

Primary Author and Speaker: Heather Roberts

Additional Authors and Speakers: Sara P. Johnston, David Plutschack

Neural responses to negative events and subsequent persistence behavior differ in individuals recovering from opioid use disorder compared to controls

Background: Negative emotion is associated with substance craving and use in individuals recovering from substance use disorders, including prescription opioid use disorder (POUD). Decisions to abandon or persist towards a goal after negative emotion-eliciting events, and neural responses that shape such decisions, may be important in maintaining recovery from POUD.Objectives: We examined differences in neural responses to negative events and subsequent persistence decisions in individuals recovering from POUD without a history of a substance use disorder. Methods: 20 individuals with POUD (POUD group: 4 females, abstinent 2-3 weeks after admission to an inpatient treatment facility post-detoxification, no other substance use disorder), and 20 individuals with no substance use history (control group: 6 females) completed a persistence-after-setbacks task during functional magnetic resonance imaging. Participants advanced along a path toward a reward; after encountering each negative event (i.e., progress-erasing setback), participants made decisions to persist or abandon the path. Persistence decision rates were compared between groups and blood-oxygen-level-dependent signal to negative events was analyzed within a striatum region of interest (ROI) as well as whole-brain.Results: The POUD group persisted less (t(38) = 2.293, p = .028, d = .725) and showed lower striatum (left ventral putamen) signal to negative events compared to the control group (p < .05, corrected for striatum ROI).Conclusions: In POUD, neural and behavioral responses to negative events differ from controls. These differences are a target for research to address whether POUD treatment increases persistence and striatum responses to negative events and improves recovery outcomes.

Efficacy and safety of abobotulinumtoxinA for upper limb spasticity in children with cerebral palsy: a randomized repeat-treatment study

AIM

To assess the efficacy and safety of repeat abobotulinumtoxinA injections in reducing upper limb spasticity in children with cerebral palsy (CP).

METHOD

This was a double-blind, repeat-cycle study (NCT02106351) in children with CP (2-17y). Children were randomized to receive 2U/kg (control), 8U/kg, or 16U/kg abobotulinumtoxinA injections into the target muscle group (wrist or elbow flexors) and additional muscles alongside occupational therapy via a home-exercise therapy program (HETP; minimum five 15min sessions/wk). Children received 8U/kg or 16U/kg plus HETP in cycles 2 to 4.

RESULTS

During cycle 1, 210 children (126 males, 84 females; mean age [SD] 9y [4y 5mo], range 2-17y; n=70/group) had at least one upper limb abobotulinumtoxinA injection and 209 complied with the HETP. At week 6 of cycle 1, children in the 8U/kg or 16U/kg groups had significantly lower Modified Ashworth scale scores versus the 2U/kg group (primary outcome: treatment differences of -0.4 [p=0.012] and -0.7 [p<0.001] respectively). All groups improved on Physician Global Assessment and children in all groups achieved their treatment goals at least as expected. Therapeutic benefits were sustained during cycles 2 to 4; muscular weakness was the only treatment-related adverse event reported in at least one child/group (4.3% and 5.7% vs 1.4% respectively).

INTERPRETATION

Treatment with 8U/kg or 16U/kg abobotulinumtoxinA significantly reduced upper limb spasticity versus the 2U/kg control dose. Therapeutic benefits of abobotulinumtoxinA plus HETP were sustained with repeat treatment cycles.

WHAT THIS PAPER ADDS

AbobotulinumtoxinA injections significantly reduced upper limb spasticity in children with cerebral palsy. Children treated with abobotulinumtoxinA and targeted home exercises showed global improvement and goal attainment. Benefits were sustained over 1 year with repeat cycles of abobotulinumtoxinA and home exercises. AbobotulinumtoxinA injections into the upper limb were well tolerated over 1 year.

The Protective Effects of Perceived Control During Repeated Exposure to Aversive Stimuli

The ability to perceive and exercise control is a major contributor to our mental and physical wellbeing. When faced with uncontrollable aversive stimuli, organisms develop heightened anxiety and become unwilling to exert effort to avoid the stimuli. In contrast, when faced with controllable aversive stimuli, organisms demonstrate behavioral vigor via avoidance attempts toward trying to seek and exercise control over the environment. As such, controllability confers protective effects against reduced avoidance motivation trigged by aversive environments. These observations beg the question of whether controllability can be potent enough to reverse passivity following repeated exposure to uncontrollable aversive stimuli and how this protective effect is encoded neurally. Human participants performed a Control in Aversive Domain (CAD) task where they were first subjected to a series of repeated uncontrollable aversive stimuli (i.e., aversive tones) across several contexts that were followed by a series of controllable aversive stimuli in a novel context. Faced with persistent uncontrollability, participants significantly reduced their avoidance attempts over time and biased toward giving up. However, the subsequent presence of controllability rescued participants' avoidance behavior. Strikingly, participants who responded more strongly to the protective effects of control also had greater ventromedial prefrontal cortical (vmPFC) activation-a region previously observed to be associated with encoding the subjective value of control. Taken together, these findings highlighted the protective effect conferred by perceived control against passivity and offered insights into the potential role of the vmPFC in controllable environments, with implications for understanding the beneficial influence of perceived control on adaptive behavior.

Germline mutation in POLR2A: a heterogeneous, multi-systemic developmental disorder characterized by transcriptional dysregulation

De novo germline variation in POLR2A was recently reported to associate with a neurodevelopmental disorder. We report twelve individuals harboring putatively pathogenic de novo or inherited variants in POLR2A, detail their phenotypes, and map all known variants to the domain structure of POLR2A and crystal structure of RNA polymerase II. Affected individuals were ascertained from a local data lake, pediatric genetics clinic, and an online community of families of affected individuals. These include six affected by de novo missense variants (including one previously reported individual), four clinical laboratory samples affected by missense variation with unknown inheritance-with yeast functional assays further supporting altered function-one affected by a de novo in-frame deletion, and one affected by a C-terminal frameshift variant inherited from a largely asymptomatic mother. Recurrently observed phenotypes include ataxia, joint hypermobility, short stature, skin abnormalities, congenital cardiac abnormalities, immune system abnormalities, hip dysplasia, and short Achilles tendons. We report a significantly higher occurrence of epilepsy (8/12, 66.7%) than previously reported (3/15, 20%) (p value = 0.014196; chi-square test) and a lower occurrence of hypotonia (8/12, 66.7%) than previously reported (14/15, 93.3%) (p value = 0.076309). POLR2A-related developmental disorders likely represent a spectrum of related, multi-systemic developmental disorders, driven by distinct mechanisms, converging at a single locus.

Constraint Induced Movement Therapy Camp for Children with Hemiplegic Cerebral Palsy Augmented by Use of an Exoskeleton to Play Games in Virtual Reality

AIM

To determine the acceptability and effects of a pediatric constraint induced movement therapy (P-CIMT) camp for children with hemiplegic cerebral palsy (hCP) augmented by use of an exoskeleton to play games in virtual reality (VR).

METHOD

31 children with hCP attended a P-CIMT camp 6 hours per day for 10 days over 2 successive weeks (60 hours) that included 30 minutes of unilateral training with the Hocoma Armeo^®Spring Pediatric that combines the assistance of an exoskeleton and VR games. The primary outcome measure was the Assisting Hand Assessment (AHA); secondary outcome measures were the Melbourne Assessment of Uni-lateral Hand Function (MUUL), and the Canadian Occupational Performance Measure (COPM). Assessments were completed at pre-intervention, post-intervention, and 6 months following intervention.

RESULTS

Participants demonstrated clinically and statistically significant improvement in bimanual performance (AHA) (p < .001) and COPM Performance (p < .001) and Satisfaction with performance (p < .001). Improvement in unilateral performance (MUUL) was statistically (p < .001) but not clinically significant.

CONCLUSIONS

A P-CIMT camp augmented by the Hocoma Armeo^®Spring Pediatric was feasible and accepted by participants. Bimanual hand function and occupational performance improved immediately following intervention, and the treatment effects persisted 6 months following intervention.

Defining the clinical, molecular and imaging spectrum of adaptor protein complex 4-associated hereditary spastic paraplegia

Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to prototypical yet poorly understood forms of childhood-onset and complex hereditary spastic paraplegia: SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). Here, we report a detailed cross-sectional analysis of clinical, imaging and molecular data of 156 patients from 101 families. Enrolled patients were of diverse ethnic backgrounds and covered a wide age range (1.0-49.3 years). While the mean age at symptom onset was 0.8 ± 0.6 years [standard deviation (SD), range 0.2-5.0], the mean age at diagnosis was 10.2 ± 8.5 years (SD, range 0.1-46.3). We define a set of core features: early-onset developmental delay with delayed motor milestones and significant speech delay (50% non-verbal); intellectual disability in the moderate to severe range; mild hypotonia in infancy followed by spastic diplegia (mean age: 8.4 ± 5.1 years, SD) and later tetraplegia (mean age: 16.1 ± 9.8 years, SD); postnatal microcephaly (83%); foot deformities (69%); and epilepsy (66%) that is intractable in a subset. At last follow-up, 36% ambulated with assistance (mean age: 8.9 ± 6.4 years, SD) and 54% were wheelchair-dependent (mean age: 13.4 ± 9.8 years, SD). Episodes of stereotypic laughing, possibly consistent with a pseudobulbar affect, were found in 56% of patients. Key features on neuroimaging include a thin corpus callosum (90%), ventriculomegaly (65%) often with colpocephaly, and periventricular white-matter signal abnormalities (68%). Iron deposition and polymicrogyria were found in a subset of patients. AP4B1-associated SPG47 and AP4M1-associated SPG50 accounted for the majority of cases. About two-thirds of patients were born to consanguineous parents, and 82% carried homozygous variants. Over 70 unique variants were present, the majority of which are frameshift or nonsense mutations. To track disease progression across the age spectrum, we defined the relationship between disease severity as measured by several rating scales and disease duration. We found that the presence of epilepsy, which manifested before the age of 3 years in the majority of patients, was associated with worse motor outcomes. Exploring genotype-phenotype correlations, we found that disease severity and major phenotypes were equally distributed among the four subtypes, establishing that SPG47, SPG50, SPG51 and SPG52 share a common phenotype, an 'AP-4 deficiency syndrome'. By delineating the core clinical, imaging, and molecular features of AP-4-associated hereditary spastic paraplegia across the age spectrum our results will facilitate early diagnosis, enable counselling and anticipatory guidance of affected families and help define endpoints for future interventional trials.

Reward-Driven Arousal Impacts Preparation to Perform a Task via Amygdala-Caudate Mechanisms

Preparing for a challenging task can increase physiological arousal, in particular when potential incentives are large (e.g., a solo musical performance in front of an audience). Here, we examine how potential reward and its influence on arousal, measured by pupil dynamics, are represented in the brain while preparing for a challenging task. We further ask how neural representations during preparation relate to actual performance. Trials resulting in performance failure were characterized by increased pupil dilation as a function of increasing reward magnitude during preparation. Such failure trials were also associated with activation of the right amygdala representing pupil dilation, and the left caudate representing reward magnitude. Notably, increases in functional connectivity between amygdala and caudate preceded performance failure. These findings highlight increased connectivity between neural regions representing reward and arousal in circumstances where reward-driven arousal impairs performance.

Duration of Symptom Relief Between Injections for AbobotulinumtoxinA (Dysport®) in Spastic Paresis and Cervical Dystonia: Comparison of Evidence From Clinical Studies

Background: Botulinum toxin-A is a well-established treatment for adult and pediatric spastic paresis and cervical dystonia. While guidelines and approved labels indicate that treatment should not occur more frequently than every 12 weeks, studies and real-world evidence show that the timing of symptom recurrence between treatments may vary. Methods: We report retreatment criteria and response duration (retreatment intervals) from four pivotal, double-blind, placebo-controlled studies with open-label extensions involving patients treated with abobotulinumtoxinA (aboBoNTA) for upper limb (NCT01313299) or lower limb (NCT01249404) spastic paresis in adults, lower limb spastic paresis in children (NCT01249417), and cervical dystonia in adults (NCT00257660). We review results in light of recently available preclinical data. Results: In spastic paresis, 24.0-36.9% of upper limb patients treated with aboBoNTA and 20.1-32.0% of lower limb patients did not require retreatment before 16 weeks. Moreover, 72.8-93.8% of aboBoNTA-treated pediatric patients with lower limb spastic paresis did not require retreatment before 16 weeks (17.7-54.0% did not require retreatment before 28 weeks). In aboBoNTA-treated patients with cervical dystonia, 72.6-81.5% did not require retreatment before 16 weeks. Conclusion: AboBoNTA, when dosed as recommended, offers symptom relief beyond 12 weeks to many patients with spastic paresis and cervical dystonia. From recently available preclinical research, the amount of active neurotoxin administered with aboBoNTA might be a factor in explaining this long duration of response.

Neural and non-neural contributions to ankle spasticity in children with cerebral palsy

AIM

To assess the neural and non-neural contributions to spasticity in the impaired ankle of children with cerebral palsy (CP).

METHOD

Instrumented tapping of the Achilles tendon was done isometrically to minimize non-neural contributions and elicit neural contributions. Robot-controlled ankle stretching was done at various velocities, including slow stretching, with minimized neural contributions. Spasticity was assessed as having neural (phasic and tonic stretch reflex torque, tendon reflex gain, contraction rate, and half relaxation rate) and non-neural origin (elastic stiffness and viscous damping) in 17 children with CP (six females and 11 males; mean age [SD] 10y 8mo [3y 11mo], range 4y-18y) and 17 typically developing children (six females and 11 males; mean age [SD] 12y 7mo [2y 9mo], range 7y-18y). All torques were normalized to weight×height.

RESULTS

Children with CP showed increased phasic and tonic stretch reflex torque (p=0.004 and p=0.001 respectively), tendon reflex gain (p=0.02), contraction rate (p=0.038), half relaxation rate (p=0.02), elastic stiffness (p=0.01), and viscous damping (p=0.01) compared to typically developing children.

INTERPRETATION

Controlled stretching and instrumented tendon tapping allow the systematic quantification of various neural and non-neural changes in CP, which can be used to guide impairment-specific treatment.

WHAT THIS PAPER ADDS

Ankle spasticity is associated with increased phasic and tonic stretch reflexes, tendon reflex gain, and contraction and half relaxation rates. Ankle spasticity is also associated with increased elastic stiffness and viscous damping.

Efficacy of Repeat AbobotulinumtoxinA (Dysport®) Injections in Improving Gait in Children with Spastic Cerebral Palsy

Purpose: This secondary analysis of a randomized, double-blind study plus open-label extension (NCT01249417/NCT01251380) evaluated the efficacy of abobotulinumtoxinA versus placebo in improving gait pattern in children with dynamic equinus due to cerebral palsy (CP) as assessed by the observational gait scale (OGS). Methods: Ambulatory children with CP (N = 241, aged 2-17) and dynamic equinus were randomized to treatment with abobotulinumtoxinA (10 or 15U/kg/leg) or placebo injected into the gastrocsoleus. All children received abobotulinumtoxinA in the open-label phase. Results: In the double-blind phase, abobotulinumtoxinA significantly improved OGS total scores versus placebo at Week 4 (treatment effect vs. placebo: 10U/kg/leg: 1.5 [0.7, 2.3], p = .0003; 15U/kg/leg: 1.1 [0.3, 1.9], p = .01). In the open-label phase, treatment with abobotulinumtoxinA continued to improve the OGS score at the same magnitude as seen in the double-blind study. Conclusion: Repeat treatment with abobotulinumtoxinA improved gait in children with dynamic equinus.

Blunted medial prefrontal cortico-limbic reward-related effective connectivity and depression

Major depressive disorder is a leading cause of disability and significant mortality, yet mechanistic understanding remains limited. Over the past decade evidence has accumulated from case-control studies that depressive illness is associated with blunted reward activation in the basal ganglia and other regions such as the medial prefrontal cortex. However it is unclear whether this finding can be replicated in a large number of subjects. The functional anatomy of the medial prefrontal cortex and basal ganglia has been extensively studied and the former has excitatory glutamatergic projections to the latter. Reduced effect of glutamatergic projections from the prefrontal cortex to the nucleus accumbens has been argued to underlie motivational disorders such as depression, and many prominent theories of major depressive disorder propose a role for abnormal cortico-limbic connectivity. However, it is unclear whether there is abnormal reward-linked effective connectivity between the medial prefrontal cortex and basal ganglia related to depression. While resting state connectivity abnormalities have been frequently reported in depression, it has not been possible to directly link these findings to reward-learning studies. Here, we tested two main hypotheses. First, mood symptoms are associated with blunted striatal reward prediction error signals in a large community-based sample of recovered and currently ill patients, similar to reports from a number of studies. Second, event-related directed medial prefrontal cortex to basal ganglia effective connectivity is abnormally increased or decreased related to the severity of mood symptoms. Using a Research Domain Criteria approach, data were acquired from a large community-based sample of subjects who participated in a probabilistic reward learning task during event-related functional MRI. Computational modelling of behaviour, model-free and model-based functional MRI, and effective connectivity dynamic causal modelling analyses were used to test hypotheses. Increased depressive symptom severity was related to decreased reward signals in areas which included the nucleus accumbens in 475 participants. Decreased reward-related effective connectivity from the medial prefrontal cortex to striatum was associated with increased depressive symptom severity in 165 participants. Decreased striatal activity may have been due to decreased cortical to striatal connectivity consistent with glutamatergic and cortical-limbic related theories of depression and resulted in reduced direct pathway basal ganglia output. Further study of basal ganglia pathophysiology is required to better understand these abnormalities in patients with depressive symptoms and syndromes.

Variability in the analysis of a single neuroimaging dataset by many teams

Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses1. The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset2-5. Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed.

The influence of relationship closeness on default-mode network connectivity during social interactions

Reciprocated trust plays a critical role in forming and maintaining relationships, and has consistently been shown to implicate neural circuits involved in reward-related processing and social cognition. Less is known about neural network connectivity during social interactions involving trust, however, particularly as a function of closeness between an investor and a trustee. We examined network reactivity and connectivity in participants who played an economic trust game with close friends, strangers and a computer. Network reactivity analyses showed enhanced activation of the default-mode network (DMN) to social relative to non-social outcomes. A novel network psychophysiological interaction (nPPI) analysis revealed enhanced connectivity between the DMN and the superior frontal gyrus and superior parietal lobule when experiencing reciprocated vs violated trust from friends relative to strangers. Such connectivity tracked with differences in self-reported social closeness with these partners. Interestingly, reactivity of the executive control network (ECN), involved in decision processes, demonstrated no social vs non-social preference, and ECN-ventral striatum connectivity did not track social closeness. Taken together, these novel findings suggest that DMN interacts with components of attention and control networks to signal the relative importance of positive experiences with close others vs strangers.

The influence of contextual factors on the subjective value of control

The propensity to perceive and exert control in our environment contributes to both our adaptive behavior and general well-being. Prior studies have shown that humans have an inherent behavioral bias toward control-conferring environments and that this bias translates into greater subjective affect and is protective of our well-being. As such, it is vital to understand contextual factors that can alter our preference for control. In our previous work, we demonstrated that the behavioral bias toward control can be captured experimentally as the subjective value of control using a novel Value of Control task. We adapted this task in two experiments to study whether one's subjective value of control is (a) tied to overestimation of success probability or outcome magnitude (Experiment 1) and (b) affected by the contextual valence of a decision (e.g., gain, loss; Experiment 2). Using a within-subjects design (Experiment 1), we found that participants showed similar behavioral bias toward control regardless of whether probability or magnitude was manipulated, suggesting that the perception of control can increase both how much a reward is subjectively worth and the probability estimation for obtaining the given reward. Using a between-subjects design (Experiment 2), we showed that when the outcome was framed as a potential loss, participants significantly lowered their subjective value of control, suggesting that outcome valence plays a role in shaping how much perceived control influences our behavior. Collectively, these findings offer further insight into the malleability of an individual's perception of control and drive to perform control-seeking behaviors. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

GATAD2B-associated neurodevelopmental disorder (GAND): clinical and molecular insights into a NuRD-related disorder

PURPOSE

Determination of genotypic/phenotypic features of GATAD2B-associated neurodevelopmental disorder (GAND).

METHODS

Fifty GAND subjects were evaluated to determine consistent genotypic/phenotypic features. Immunoprecipitation assays utilizing in vitro transcription-translation products were used to evaluate GATAD2B missense variants' ability to interact with binding partners within the nucleosome remodeling and deacetylase (NuRD) complex.

RESULTS

Subjects had clinical findings that included macrocephaly, hypotonia, intellectual disability, neonatal feeding issues, polyhydramnios, apraxia of speech, epilepsy, and bicuspid aortic valves. Forty-one novelGATAD2B variants were identified with multiple variant types (nonsense, truncating frameshift, splice-site variants, deletions, and missense). Seven subjects were identified with missense variants that localized within two conserved region domains (CR1 or CR2) of the GATAD2B protein. Immunoprecipitation assays revealed several of these missense variants disrupted GATAD2B interactions with its NuRD complex binding partners.

CONCLUSIONS

A consistent GAND phenotype was caused by a range of genetic variants in GATAD2B that include loss-of-function and missense subtypes. Missense variants were present in conserved region domains that disrupted assembly of NuRD complex proteins. GAND's clinical phenotype had substantial clinical overlap with other disorders associated with the NuRD complex that involve CHD3 and CHD4, with clinical features of hypotonia, intellectual disability, cardiac defects, childhood apraxia of speech, and macrocephaly.

Correction: GATAD2B-associated neurodevelopmental disorder (GAND): clinical and molecular insights into a NuRD-related disorder

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Corticostriatal Circuits Encode the Subjective Value of Perceived Control

The ability to perceive and exercise control over an outcome is both desirable and beneficial to our well-being. It has been shown that animals and humans alike exhibit behavioral bias towards seeking control and that such bias recruits the ventromedial prefrontal cortex (vmPFC) and striatum. Yet, this bias remains to be quantitatively captured and studied neurally. Here, we employed a behavioral task to measure the preference for control and characterize its neural underpinnings. Participants made a series of binary choices between having control and no-control over a game for monetary reward. The mere presence of the control option evoked activity in the ventral striatum. Importantly, we manipulated the expected value (EV) of each choice pair to extract the pairing where participants were equally likely to choose either option. The difference in EV between the options at this point of equivalence was inferred as the subjective value of control. Strikingly, perceiving control inflated the reward value of the associated option by 30% and this value inflation was tracked by the vmPFC. Altogether, these results capture the subjective value of perceived control inherent in decision making and highlight the role of corticostriatal circuitry in the perception of control.

DYRK1A-related intellectual disability: a syndrome associated with congenital anomalies of the kidney and urinary tract

PURPOSE

Haploinsufficiency of DYRK1A causes a recognizable clinical syndrome. The goal of this paper is to investigate congenital anomalies of the kidney and urinary tract (CAKUT) and genital defects (GD) in patients with DYRK1A variants.

METHODS

A large database of clinical exome sequencing (ES) was queried for de novo DYRK1A variants and CAKUT/GD phenotypes were characterized. Xenopus laevis (frog) was chosen as a model organism to assess Dyrk1a's role in renal development.

RESULTS

Phenotypic details and variants of 19 patients were compiled after an initial observation that one patient with a de novo pathogenic variant in DYRK1A had GD. CAKUT/GD data were available from 15 patients, 11 of whom presented with CAKUT/GD. Studies in Xenopus embryos demonstrated that knockdown of Dyrk1a, which is expressed in forming nephrons, disrupts the development of segments of embryonic nephrons, which ultimately give rise to the entire genitourinary (GU) tract. These defects could be rescued by coinjecting wild-type human DYRK1A RNA, but not with DYRK1AR205* or DYRK1AL245R RNA.

CONCLUSION

Evidence supports routine GU screening of all individuals with de novo DYRK1A pathogenic variants to ensure optimized clinical management. Collectively, the reported clinical data and loss-of-function studies in Xenopus substantiate a novel role for DYRK1A in GU development.

TBX6 missense variants expand the mutational spectrum in a non-Mendelian inheritance disease

Congenital scoliosis (CS) is a birth defect with variable clinical and anatomical manifestations due to spinal malformation. The genetic etiology underlying about 10% of CS cases in the Chinese population is compound inheritance by which the gene dosage is reduced below that of haploinsufficiency. In this genetic model, the trait manifests as a result of the combined effect of a rare variant and common pathogenic variant allele at a locus. From exome sequencing (ES) data of 523 patients in Asia and two patients in Texas, we identified six TBX6 gene-disruptive variants from 11 unrelated CS patients via ES and in vitro functional testing. The in trans mild hypomorphic allele was identified in 10 of the 11 subjects; as anticipated these 10 shared a similar spinal deformity of hemivertebrae. The remaining case has a homozygous variant in TBX6 (c.418C>T) and presents a more severe spinal deformity phenotype. We found decreased transcriptional activity and abnormal cellular localization as the molecular mechanisms for TBX6 missense loss-of-function alleles. Expanding the mutational spectrum of TBX6 pathogenic alleles enabled an increased molecular diagnostic detection rate, provided further evidence for the gene dosage-dependent genetic model underlying CS, and refined clinical classification.

Cohesin complex-associated holoprosencephaly

Marked by incomplete division of the embryonic forebrain, holoprosencephaly is one of the most common human developmental disorders. Despite decades of phenotype-driven research, 80-90% of aneuploidy-negative holoprosencephaly individuals with a probable genetic aetiology do not have a genetic diagnosis. Here we report holoprosencephaly associated with variants in the two X-linked cohesin complex genes, STAG2 and SMC1A, with loss-of-function variants in 10 individuals and a missense variant in one. Additionally, we report four individuals with variants in the cohesin complex genes that are not X-linked, SMC3 and RAD21. Using whole mount in situ hybridization, we show that STAG2 and SMC1A are expressed in the prosencephalic neural folds during primary neurulation in the mouse, consistent with forebrain morphogenesis and holoprosencephaly pathogenesis. Finally, we found that shRNA knockdown of STAG2 and SMC1A causes aberrant expression of HPE-associated genes ZIC2, GLI2, SMAD3 and FGFR1 in human neural stem cells. These findings show the cohesin complex as an important regulator of median forebrain development and X-linked inheritance patterns in holoprosencephaly.

The social value of positive autobiographical memory retrieval

Positive memory retrieval generates pleasant feelings that can counteract negative affective states and improve mood. However, not all positive memories are created equal. Our most treasured memories are likely experiences we shared with other people (e.g., birthday party) rather than something we did alone (e.g., receiving good grades). Here, we explored whether the social context within a positive memory enhanced its subjective value and contributed to an individual's well-being. In Study 1, participants were asked how much they would be willing to pay to reexperience positive memories that occurred with socially close others (high-social), with acquaintances (low-social) or alone (nonsocial). When controlling for the memory's positivity, participants were still willing to pay 1.5 times as much for high-social than for low-social or nonsocial memories. Likewise, participants chose to reminisce about high-social memories more frequently than less social ones of equal positive feeling. In Study 2, recalling memories rich in social context recruited regions previously implicated in mentalizing and reward (e.g., caudate), which further correlated with greater ability to savor positive emotions in daily life. Finally, we examined the benefit of social context by asking participants to recall positive memories that varied in social context after acute stress exposure. In Study 3, recalling memories that included higher social context led to a greater dampening of the physiological stress response (i.e., cortisol). Taken together, these findings suggest that social context inherent in a positive memory enhances its value, providing a possible mechanism by which positive reminiscence aids stress coping and enhances well-being. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

2-Pyrrolidinone and Succinimide as Clinical Screening Biomarkers for GABA-Transaminase Deficiency: Anti-seizure Medications Impact Accurate Diagnosis

Broad-scale untargeted biochemical phenotyping is a technology that supplements widely accepted assays, such as organic acid, amino acid, and acylcarnitine analyses typically utilized for the diagnosis of inborn errors of metabolism. In this study, we investigate the analyte changes associated with 4-aminobutyrate aminotransferase (ABAT, GABA transaminase) deficiency and treatments that affect GABA metabolism. GABA-transaminase deficiency is a rare neurodevelopmental and neurometabolic disorder caused by mutations in ABAT and resulting in accumulation of GABA in the cerebrospinal fluid (CSF). For that reason, measurement of GABA in CSF is currently the primary approach to diagnosis. GABA-transaminase deficiency results in severe developmental delay with intellectual disability, seizures, and movement disorder, and is often associated with death in childhood. Using an untargeted metabolomics platform, we analyzed EDTA plasma, urine, and CSF specimens from four individuals with GABA-transaminase deficiency to identify biomarkers by comparing the biochemical profile of individual patient samples to a pediatric-centric population cohort. Metabolomic analyses of over 1,000 clinical plasma samples revealed a rich source of biochemical information. Three out of four patients showed significantly elevated levels of the molecule 2-pyrrolidinone (Z-score ≥2) in plasma, and whole exome sequencing revealed variants of uncertain significance in ABAT. Additionally, these same patients also had elevated levels of succinimide in plasma, urine, and CSF and/or homocarnosine in urine and CSF. In the analysis of clinical EDTA plasma samples, the levels of succinimide and 2-pyrrolidinone showed a high level of correlation (R = 0.73), indicating impairment in GABA metabolism and further supporting the association with GABA-transaminase deficiency and the pathogenicity of the ABAT variants. Further analysis of metabolomic data across our patient population revealed the association of elevated levels of 2-pyrrolidinone with administration of vigabatrin, a commonly used anti-seizure medication and a known inhibitor of GABA-transaminase. These data indicate that anti-seizure medications may alter the biochemical and metabolomic data, potentially impacting the interpretation and diagnosis for the patient. Further, these data demonstrate the power of combining broad scale genotyping and phenotyping technologies to diagnose inherited neurometabolic disorders and support the use of metabolic phenotyping of plasma to screen for GABA-transaminase deficiency.

A Reward-Based Framework of Perceived Control

Perceived control can be broadly defined as the belief in one's ability to exert control over situations or events. It has long been known that perceived control is a major contributor toward mental and physical health as well as a strong predictor of achievements in life. However, one issue that limits a mechanistic understanding of perceived control is the heterogeneity of how the term is defined in models in psychology and neuroscience, and used in experimental settings across a wide spectrum of studies. Here, we propose a framework for studying perceived control by integrating the ideas from traditionally separate work on perceived control. Specifically, we discuss key properties of perceived control from a reward-based framework, including choice opportunity, instrumental contingency, and success/reward rate. We argue that these separate reward-related processes are integral to fostering an enhanced perception of control and influencing an individual's behavior and well-being. We draw on select studies to elucidate how these reward-related elements are implicated separately and collectively in the investigation of perceived control. We highlight the role of dopamine within corticostriatal pathways shared by reward-related processes and perceived control. Finally, through the lens of this reward-based framework of perceived control, we consider the implications of perceived control in clinical deficits and how these insights could help us better understand psychopathology and treatment options.

Development of a Pediatric Goal-Centered Upper Limb Spasticity Home Exercise Therapy Program for Use in a Phase-III Trial of Abobotulinumtoxina (Dysport®)

AIMS

To create a standardized home exercise therapy program that could be implemented by international sites to provide a consistent level of therapeutic intervention for pediatric patients participating in an ongoing Phase-III, randomized, controlled trial of repeat abobotulinumtoxinA injections for pediatric upper limb spasticity (NCT02106351).

METHODS

Physical therapists, occupational therapists, and medical doctors worked collaboratively to design an exercise therapy program to be implemented in the home setting. In this article, we describe the development process and the finalized program that is currently being used in the Phase-III trial.

RESULTS

The final program is presented as a "toolbox" for therapists, and includes a standardized step-wise process for choosing the most appropriate exercises and functional activities to achieve the agreed treatment goals of each abobotulinumtoxinA injection. The core toolbox includes: a clear protocol for clinicians, information sheets, signature of commitment forms, exercise score charts, and the library of exercises and functional activities that therapists choose from to aid the patient in achieving their treatment goals.

CONCLUSIONS

Implementation of this home therapy program provides a standardized background of good practice against which to test the efficacy of abobotulinumtoxinA. Preliminary data show that the program is readily accepted by patients and their families.

Neural mechanisms of extinguishing drug and pleasant cue associations in human addiction: role of the VMPFC

The neurobiological mechanisms that underlie the resistance of drug cue associations to extinction in addiction remain unknown. Fear extinction critically depends on the ventromedial prefrontal cortex (VMPFC). Here, we tested if this same region plays a role in extinction of non-fear, drug and pleasant cue associations. Eighteen chronic cocaine users and 15 matched controls completed three functional MRI scans. Participants first learned to associate an abstract cue (the conditioned stimulus, CS) with a drug-related (CS_D+ ) or pleasant (CS_P+ ) image. Extinction immediately followed where each CS was repeatedly presented without the corresponding image. Participants underwent a second identical session 24 hours later to assess retention of extinction learning. Results showed that like fear extinction, non-fear-based extinction relies on the VMPFC. However, extinction-related changes in the VMPFC differed by cue valence and diagnosis. In controls, VMPFC activation to the CS_D+ (which was unpleasant for participants) gradually increased as in fear extinction, while it decreased to the CS_P+ , consistent with a more general role of the VMPFC in flexible value updating. Supporting a specific role in extinction retention, we further observed a cross-day association between VMPFC activation and skin conductance, a classic index of conditioned responses. Finally, cocaine users showed VMPFC abnormalities for both CSs, which, in the case of the CS_D+ , correlated with craving. These data suggest a global deficit in extinction learning in this group that may hinder extinction-based treatment efforts. More broadly, these data show that the VMPFC, when functionally intact, supports extinction learning in diverse contexts in humans.

The Neurobiology of Personal Control During Reward Learning and Its Relationship to Mood

BACKGROUND

The majority of reward learning neuroimaging studies have not focused on the motivational aspects of behavior, such as the inherent value placed on choice itself. The experience and affective value of personal control may have particular relevance for psychiatric disorders, including depression.

METHODS

We adapted a functional magnetic resonance imaging reward task that probed the value placed on exerting control over one's decisions, termed choice value, in 122 healthy participants. We examined activation associated with choice value; personally chosen versus passively received rewards; and reinforcement learning metrics, such as prediction error. Relationships were tested between measures of motivational orientation (categorized as autonomy, control, and impersonal) and subclinical depressive symptoms.

RESULTS

Anticipating personal choice activated left insula, cingulate, right inferior frontal cortex, and ventral striatum (p_{familywise error-corrected} < .05). Ventral striatal activations to choice were diminished in participants with subclinical depressive symptoms. Personally chosen rewards were associated with greater activation of the insula and inferior frontal gyrus, cingulate cortex, hippocampus, thalamus, and substantia nigra compared with rewards that were passively received. In participants who felt they had little control over their own behavior (impersonal orientation), prediction error signals in nucleus accumbens were stronger during passive trials.

CONCLUSIONS

Previous findings regarding personal choice have been verified and advanced through the use of both reinforcement learning models and correlations with psychopathology. Personal choice has an impact on the extended reward network, potentially allowing these clinically important areas to be addressed in ways more relevant to personality styles, self-esteem, and symptoms such as motivational anhedonia.

AbobotulinumtoxinA Efficacy and Safety in Children With Equinus Foot Previously Treated With Botulinum Toxin

BACKGROUND

The effects of botulinum toxin are transient, and repeat injections are required in children with lower-limb spasticity. However, the efficacy of botulinum toxin in patients who have received previous injections has remained largely unexplored.

METHODS

We present subgroup analyses of a phase III study conducted in ambulatory children (aged two to 17) with spastic equinus foot. Patients were randomized to single doses of abobotulinumtoxinA 10 U/kg/leg, 15 U/kg/leg, or placebo injected into the gastrocnemius-soleus complex (one or both legs). The first analysis was prespecified to review the effect of abobotulinumtoxinA in children previously treated with botulinum toxin versus those children new to the treatment; a second post hoc analysis evaluated the effect of abobotulinumtoxinA in children who changed botulinum toxin formulation.

RESULTS

Of the 241 randomized patients, 113 had previously received botulinum toxin, including 86 who had been treated with another formulation. In both analyses, muscle tone (Modified Ashworth Scale) and the Physicians Global Assessment, at week 4, improved with abobotulinumtoxinA treatment versus placebo, regardless of baseline botulinum toxin status. Placebo responses in patients new to treatment were consistently higher than in the previously treated group.

CONCLUSIONS

These results demonstrate similar abobotulinumtoxinA efficacy and safety profiles in children with spasticity who are new to botulinum toxin treatment and those children who were previously treated. The efficacy and safety of abobotulinumtoxinA treatment in these previously treated patients were comparable with the overall trial population, indicating that doses of 10 and 15 U/kg/leg are suitable starting doses for children with spasticity regardless of the previous botulinum toxin preparation used.

Toe Walking: A Neurological Perspective After Referral From Pediatric Orthopaedic Surgeons

BACKGROUND

Toe walking (TW) in children is often idiopathic in origin. Our purpose was to determine the incidence of a neurological etiology for TW in patients seen in the neurology clinic after referral from pediatric orthopaedic surgeons.

METHODS

We performed an Institutional Review Board approved retrospective review of 174 patients referred to the neurology clinic from orthopaedic surgeons at an academic pediatric tertiary care center between January 2010 and September 2015. Medical records were reviewed and data recorded including pertinent family history, birth history, age of initial ambulation, physical examination findings, and workup results including neuroimaging, neurophysiological studies, and findings of genetic testing and tissue biopsy.

RESULTS

Sixty-two percent (108/174) of patients were found to have a neurological etiology for TW. Final pathologic diagnoses were: 37% (40/108) previously undiagnosed cerebral palsy (CP), 16.7% (18/108) peripheral neuropathy, 15.7% (17/108) autism spectrum disorder, 13.9% (15/108) hereditary spastic paraparesis, 8.3% (9/108) attention deficit hyperactivity disorder, 5.6% (6/108) syndromic diagnosis, and 2.8% (3/108) spinal cord abnormality. Ankle equinus contractures were noted in idiopathic and neurological patients and did not indicate a pathologic origin. Seventy-one percent of unilateral toe walkers and 32% of bilateral but asymmetric toe walkers were diagnosed with CP (P<0.001). Twenty-six percent of 145 brain magnetic resonance imaging studies diagnosed CP. Of the 125 (72%) with spinal imaging, 3 had spinal pathology to account for TW. Fourteen percent of 87 subjects with an electromyography/nerve conduction study had abnormal results indicating a peripheral polyneuropathy.

CONCLUSIONS

An underlying pathologic diagnosis was found in 62% of patients referred to neurology for TW. A concerning birth history, delayed initial ambulation, unilateral TW, upper or lower motor neuron signs on examination, or behavioral features may suggest a pathologic diagnosis. Ankle contracture is not predictive of an abnormal diagnosis and can be found in idiopathic patients. CP, peripheral neuropathy, autism spectrum disorder, and hereditary spastic paraparesis are the most common pathologic diagnoses identified in our population.

LEVEL OF EVIDENCE

Level III-retrospective cohort.

Pavlovian-to-Instrumental Transfer of Nicotine and Food Cues in Deprived Cigarette Smokers

Introduction

Smoking-related cues can promote drug-seeking behavior and curtail attempts to quit. One way to understand the potential impact of such cues is to compare cue-elicited behaviors for smoking and other reinforcers (eg, food) using the Pavlovian-to-instrumental transfer paradigm, which measures how much control cues can exert over reward-seeking responses.

Methods

We tested the influence of appetitive cues on smokers' behavior following 12 hours of abstinence from smoking and eating. First, we equated the value of cigarette and food by assessing a Willingness-to-Pay measure for each reinforcer. Second, we evaluated behavioral differences between cues with Pavlovian-to-instrumental transfer. In two phases, participants learned (1) the association between distinct stimuli and cigarette or food outcomes and, (2) specific instrumental responses that yielded such outcomes. Motivated behavior was probed under extinction in a subsequent transfer test assessing instrumental responding in the presence of the cues.

Results

Participants showed an increase in specific responding (eg, instrumental response associated with cigarette) when faced with the corresponding appetitive cue (eg, stimulus associated with cigarette) despite absence of outcome. Notably, they made more cigarette-seeking than food-seeking instrumental responses, suggesting that cues representative of cigarette outcomes exert stronger influences on behavior than non-drug (food) cues. Using a measure of subjective preference, we also observed that greater preference for cigarette-compared to food-cues correlated with increased cigarette-seeking behavior in the test phase.

Conclusion

Taken together, these results highlight how drug and non-drug cues differentially influence reward-seeking behaviors during deprivation, which has implications for smoking cessation treatment and relapse.

Implications

This study examines the motivational influence of both drug and non-drug cues within a single sample of cigarette smokers. Our results demonstrate that the motivational properties of smoking cues differ from cues relating to other types of reward, such as food. This research informs smoking cessation programs to target the salience of nicotine cues and the maladaptive drug-seeking behaviors prompted by them.

Safety and Efficacy of Repeat Open-Label AbobotulinumtoxinA Treatment in Pediatric Cerebral Palsy

This was a prospective, repeat-treatment, open-label study (NCT01251380) of abobotulinumtoxinA for the management of lower limb spasticity in children who had completed a double-blind study. Children (2-17 years) received injections into the gastrocnemius-soleus complex, and other distal and proximal muscles as required (maximum total dose per injection cycle: 30 U/kg or 1000U). A total of 216 of the 241 double-blind patients entered the extension study and 207 received ≥1 open label injection into the gastrocnemius-soleus; 17-24% of patients also had injections into the hamstrings. The most frequent adverse events were related to common childhood infections and the most frequent treatment-related adverse event was injection site pain (n = 10). There was no evidence of a cumulative effect on adverse events. Sustained significant clinical improvements in muscle tone (Modified Ashworth Scale), spasticity (Tardieu Scale), overall clinical benefit (Physicians Global Assessment), and goal attainment (Goal Attainment Scale) were also observed across treatment cycles.