A Retrospective, Cross-Sectional Analysis of Motor Development, Cognition, and Mood in 87 Patients With Childhood-Onset Hereditary Spastic Paraplegias.

BACKGROUND: HSP is a heterogeneous group of rare genetic diseases. In childhood, little is known of the development and psychological manifestations. METHODS: Retrospective analysis of 87 patients with childhood-onset HSP. Patient consent was obtained and data regarding gross motor, fine motor, and language development; equipment usage; surgical procedures; cognition; and mood were collected at each clinic visit and by phone call and analyzed using mean, median, range, and interquartile ranges (IQRs). RESULTS: The cohort contained 18 genetic types of HSP. Participant data ranged from birth to 36 years. Follow-up was variable spanning from a single clinic visit to 24 years of longitudinal visits. The mean age in months of sitting = 7.37, median = 6, range = 5 to 48, IQR = 0; crawling mean = 9.6, median = 9, range 7 to 23, IQR = 0; pulling to stand mean = 10.7, median 9, range: 9 to 36, IQR = 0; and the age for walking was mean = 16.25, median = 15, range = 11 to 63 IQR = 6. Eighteen patients did not achieve independent ambulation. Twenty-five were noted to have initial gait abnormalities. Median age for first word spoken was 12 months. Fifty-five of 87 participants were enrolled in mainstream or honors classes. Twenty-two of 87 had attention deficit disorder. Patients reported experiencing sadness around their diagnoses, and 26 of 87 reported being diagnosed with anxiety or depression. CONCLUSIONS: In childhood-onset HSP, motor disorder is the predominant feature; however, screening for attention deficit, anxiety, and depression is indicated.

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.

Early-Onset and Severe Complex Hereditary Spastic Paraplegia Caused by De Novo Variants in SPAST.

BACKGROUND: Familial hereditary spastic paraplegia (HSP)-SPAST (SPG4) typically presents with a pure HSP phenotype. OBJECTIVE: The aim of this study was to delineate the genotypic and phenotypic spectrum of children with de novo HSP-SPAST. METHODS: This study used a systematic cross-sectional analysis of clinical and molecular features. RESULTS: We report the clinical and molecular spectrum of 40 patients with heterozygous pathogenic de novo variants in SPAST (age range: 2.2-27.7 years). We identified 19 unique variants (16/40 carried the same recurrent variant, p.Arg499His). Symptom onset was in early childhood (median: 11.0 months, interquartile range: 6.0 months) with significant motor and speech delay, followed by progressive ascending spasticity, dystonia, neurogenic bladder dysfunction, gastrointestinal dysmotility, and epilepsy. The mean Spastic Paraplegia Rating Scale score was 32.8 ± 9.7 (standard deviation). CONCLUSIONS: These results confirm that de novo variants in SPAST lead to a severe and complex form of HSP that differs from classic familial pure HSP-SPAST. Clinicians should be aware of this syndrome in the differential diagnosis for cerebral palsy. © 2022 International Parkinson and Movement Disorder Society.

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.

Evaluation of cortical plasticity in children with cerebral palsy undergoing constraint-induced movement therapy based on functional near-infrared spectroscopy.

Sensorimotor cortex plasticity induced by constraint-induced movement therapy (CIMT) in six children (10.2±2.1 years old) with hemiplegic cerebral palsy was assessed by functional near-infrared spectroscopy (fNIRS). The activation laterality index and time-to-peak/duration during a finger-tapping task and the resting-state functional connectivity were quantified before, immediately after, and 6 months after CIMT. These fNIRS-based metrics were used to help explain changes in clinical scores of manual performance obtained concurrently with imaging time points. Five age-matched healthy children (9.8±1.3 years old) were also imaged to provide comparative activation metrics for normal controls. Interestingly, the activation time-to-peak/duration for all sensorimotor centers displayed significant normalization immediately after CIMT that persisted 6 months later. In contrast to this improved localized activation response, the laterality index and resting-state connectivity metrics that depended on communication between sensorimotor centers improved immediately after CIMT, but relapsed 6 months later. In addition, for the subjects measured in this work, there was either a trade-off between improving unimanual versus bimanual performance when sensorimotor activation patterns normalized after CIMT, or an improvement occurred in both unimanual and bimanual performance but at the cost of very abnormal plastic changes in sensorimotor activity.

Motion tracking and electromyography-assisted identification of mirror hand contributions to functional near-infrared spectroscopy images acquired during a finger-tapping task performed by children with cerebral palsy.

Recent studies have demonstrated functional near-infrared spectroscopy (fNIRS) to be a viable and sensitive method for imaging sensorimotor cortex activity in children with cerebral palsy (CP). However, during unilateral finger tapping, children with CP often exhibit unintended motions in the nontapping hand, known as mirror motions, which confuse the interpretation of resulting fNIRS images. This work presents a method for separating some of the mirror motion contributions to fNIRS images and demonstrates its application to fNIRS data from four children with CP performing a finger-tapping task with mirror motions. Finger motion and arm muscle activity were measured simultaneously with fNIRS signals using motion tracking and electromyography (EMG), respectively. Subsequently, subject-specific regressors were created from the motion capture or EMG data and independent component analysis was combined with a general linear model to create an fNIRS image representing activation due to the tapping hand and one image representing activation due to the mirror hand. The proposed method can provide information on how mirror motions contribute to fNIRS images, and in some cases, it helps remove mirror motion contamination from the tapping hand activation images.

Quantification of functional near infrared spectroscopy to assess cortical reorganization in children with cerebral palsy.

Cerebral palsy (CP) is the most common motor disorder in children. Currently available neuroimaging techniques require complete body confinement and steadiness and thus are extremely difficult for pediatric patients. Here, we report the use and quantification of functional near infrared spectroscopy (fNIRS) to investigate the functional reorganization of the sensorimotor cortex in children with hemiparetic CP. Ten of sixteen children with congenital hemiparesis were measured during finger tapping tasks and compared with eight of sixteen age-matched healthy children, with an overall measurement success rate of 60%. Spatiotemporal analysis was introduced to quantify the motor activation and brain laterality. Such a quantitative approach reveals a consistent, contralateral motor activation in healthy children at 7 years of age or older. In sharp contrast, children with congenital hemiparesis exhibit all three of contralateral, bilateral and ipsilateral motor activations, depending on specific ages of the pediatric subjects. This study clearly demonstrates the feasibility of fNIRS to be utilized for investigating cortical reorganization in children with CP or other cortical disorders.

Identification of abnormal motor cortex activation patterns in children with cerebral palsy by functional near-infrared spectroscopy.

We demonstrate the utility of functional near-infrared spectroscopy (fNIRS) as a tool for physicians to study cortical plasticity in children with cerebral palsy (CP). Motor cortex activation patterns were studied in five healthy children and five children with CP (8.4+/-2.3 years old in both groups) performing a finger-tapping protocol. Spatial (distance from center and area difference) and temporal (duration and time-to-peak) image metrics are proposed as potential biomarkers for differentiating abnormal cortical activation in children with CP from healthy pediatric controls. In addition, a similarity image-analysis concept is presented that unveils areas that have similar activation patterns as that of the maximum activation area, but are not discernible by visual inspection of standard activation images. Metrics derived from the images presenting areas of similarity are shown to be sensitive identifiers of abnormal activation patterns in children with CP. Importantly, the proposed similarity concept and related metrics may be applicable to other studies for the identification of cortical activation patterns by fNIRS.