Optimization of fMRI methods to determine laterality of cortical activation during ankle movements of children with unilateral cerebral palsy

Functional Neuroplasticity and Motor Skill Change Following Gross Motor Interventions for Children With Diplegic Cerebral Palsy

BACKGROUND

Gross motor intervention designs for children with diplegic cerebral palsy (DCP) require an improved understanding of the children's potential for neuroplasticity.

OBJECTIVE

To identify relations between functional neuroplasticity and motor skill changes following gross motor interventions for children with DCP.

METHODS

There were 17 participants with DCP (ages 8-16 years; 6 females; Gross Motor Function Classification System Level I [n = 9] and II [n = 8]). Each completed a 6-week gross motor intervention program that was directed toward achievement of individualized motor/physical activity goals. Outcomes were assessed pre/post and 4 to 6 months post-intervention (follow-up). An active ankle dorsiflexion task was completed during functional magnetic resonance imaging. The ratio of motor cortical activation volume in each hemisphere was calculated using a laterality index. The Challenge was the primary gross motor skill measure. Change over time and relations among outcomes were evaluated.

RESULTS

Challenge scores improved post-intervention (4.57% points [SD 4.45], P = .004) and were maintained at follow-up (0.75% [SD 6.57], P = 1.000). The laterality index for dominant ankle dorsiflexion increased (P = .033), while non-dominant change was variable (P = .534). Contralateral activation (laterality index ≥+0.75) was most common for both ankles. Challenge improvements correlated with increased ipsilateral activity (negative laterality index) during non-dominant dorsiflexion (r = -.56, P = .045). Smaller activation volume during non-dominant dorsiflexion predicted continued gross motor gains at follow-up (R² = .30, P = .040).

CONCLUSIONS

Motor cortical activation during non-dominant ankle dorsiflexion is a modest indicator of the potential for gross motor skill change. Further investigation of patterns of neuroplastic change will improve our understanding of effects.

CLINICALTRIALS.GOV REGISTRY

NCT02584491 and NCT02754128.

Weaker Connectivity of the Cortical Networks Is Linked with the Uncharacteristic Gait in Youth with Cerebral Palsy

Cerebral palsy (CP) is the most prevalent pediatric neurologic impairment and is associated with major mobility deficiencies. This has led to extensive investigations of the sensorimotor network, with far less research focusing on other major networks. The aim of this study was to investigate the functional connectivity (FC) of the main sensory networks (i.e., visual and auditory) and the sensorimotor network, and to link FC to the gait biomechanics of youth with CP. Using resting-state functional magnetic resonance imaging, we first identified the sensorimotor, visual and auditory networks in youth with CP and neurotypical controls. Our analysis revealed reduced FC among the networks in the youth with CP relative to the controls. Notably, the visual network showed lower FC with both the sensorimotor and auditory networks. Furthermore, higher FC between the visual and sensorimotor cortices was associated with larger step length (r = 0.74, p_FDR = 0.04) in youth with CP. These results confirm that CP is associated with functional brain abnormalities beyond the sensorimotor network, suggesting abnormal functional integration of the brain’s motor and primary sensory systems. The significant association between abnormal visuo-motor FC and gait could indicate a link with visuomotor disorders in this patient population.

Functional connectivity and quality of life in young adults with cerebral palsy: a feasibility study

BACKGROUND

Cerebral Palsy (CP) is a group of disorders that affect the development of movement and posture. CP results from injuries to the immature brain during the prenatal, perinatal, or postnatal stage of development. Neuroimaging research in CP has focused on the structural changes of the brain during early development, but little is known about brain's structural and functional changes during late adolescence and early adulthood, a period in time when individuals experience major changes as they transition into adulthood. The work reported here served as a feasibility study within a larger program of research (MyStory Study). We aimed to determine whether it would be feasible to scan and obtain good quality data without the use of sedation during a resting state condition for functional connectivity (FC) analyses in young adults with CP. Second, we aimed to identify the FC pattern(s) that are associated with depressive mood ratings, indices of pain and fatigue, and quality of life in this group.

METHODS

Resting state functional images were collected from 9 young people with CP (18-29 years). We applied a stringent head motion correction and quality control methods following preprocessing.

RESULTS

We were able to scan and obtain good quality data without the use of sedation from this group of young individuals with CP who demonstrated a range of gross motor ability. The functional connectivity networks of interest were identified in the data using standard seed regions. Our analyses further revealed that higher well-being scores were associated with higher levels of FC between the Medial Pre-Frontal Cortex and the right Lateral Parietal regions, which are implicated in prosocial and emotion regulations skills. The implications of this association are discussed.

CONCLUSION

The findings of the present study demonstrate that it is feasible to conduct resting state functional connectivity in young adults with CP with different gross motor abilities without the use of sedation. Our results also highlight a neural circuitry that is associated with the self-report of quality of life and emotion regulation. These findings identify these regions/circuitries as important seeds for further investigations into mental health and wellbeing in CP.

Functional near-infrared spectroscopy to assess sensorimotor cortical activity during hand squeezing and ankle dorsiflexion in individuals with and without bilateral and unilateral cerebral palsy

Significance: Our study is the first comparison of brain activation patterns during motor tasks across unilateral cerebral palsy (UCP), bilateral cerebral palsy (BCP), and typical development (TD) to elucidate neural mechanisms and inform rehabilitation strategies. Aim: Cortical activation patterns were compared for distal upper and lower extremity tasks in UCP, BCP, and TD using functional near-infrared spectroscopy (fNIRS) and related to functional severity. Approach: Individuals with UCP ( n = 10 , 18.8 ± 6.8    years ), BCP ( n = 14 , 17.5 ± 9.6    years ), and TD ( n = 16 , 17.3 ± 9.1    years ) participated in this cross-sectional cohort study. The fNIRS was used to noninvasively monitor the hemodynamic response to task-related cortical activation. The block design involved repetitive nondominant hand squeezing and ankle dorsiflexion. Results: Individuals with UCP demonstrated the highest levels of activation for the squeeze task ( UCP > BCP q = 0.049 ; BCP > TD q < 0.001 ; and UCP > TD q = 0.001 ) and more activity in the ipsilateral versus contralateral hemisphere. Individuals with BCP showed the highest levels of cortical activation in the dorsiflexion task ( BCP > UCP q < 0.001 ; BCP > TD ). Conclusions: Grouping by CP subtype and manual function or mobility level demonstrated significant differences from TD, even for individuals with the mildest forms of CP. Hemispheric activation patterns showed hypothesized but nonsignificant trends.

Brain Metabolism During A Lower Extremity Voluntary Movement Task in Children With Spastic Cerebral Palsy

Reduced selective voluntary motor control (SVMC) is a primary impairment due to corticospinal tract (CST) injury in spastic cerebral palsy (CP). There are few studies of brain metabolism in CP and none have examined brain metabolism during a motor task. Nine children with bilateral spastic CP [Age: 6-11 years, Gross Motor Function Classification System (GMFCS) Levels II-V] completed this study. SVMC was evaluated using Selective Control Assessment of the Lower Extremity (SCALE) ranging from 0 (absent) to 10 (normal). Brain metabolism was measured using positron emission tomography (PET) scanning in association with a selective ankle motor task. Whole brain activation maps as well as ROI averaged metabolic activity were correlated with SCALE scores. The contralateral sensorimotor and superior parietal cortex were positively correlated with SCALE scores (p < 0.0005). In contrast, a negative correlation of metabolic activity with SCALE was found in the cerebellum (p < 0.0005). Subsequent ROI analysis showed that both ipsilateral and contralateral cerebellar metabolism correlated with SCALE but the relationship for the ipsilateral cerebellum was stronger (R ² = 0.80, p < 0.001 vs. R ² = 0.46, p = 0.045). Decreased cortical and increased cerebellar activation in children with less SVMC may be related to task difficulty, activation of new motor learning paradigms in the cerebellum and potential engagement of alternative motor systems when CSTs are focally damaged. These results support SCALE as a clinical correlate of neurological impairment.

Divergent Findings in Brain Reorganization After Spinal Cord Injury: A Review

Spinal cord injury (SCI) leads to a general lack of sensory and motor functions below the level of injury and may promote deafferentation-induced brain reorganization. Functional magnetic resonance imaging (fMRI) has been established as an essential tool in neuroscience research and can precisely map the spatiotemporal distribution of brain activity. Task-based fMRI experiments associated with the tongue, upper limbs, or lower limbs have been used as the primary paradigms to study brain reorganization following SCI. A review of the current literature on the subject shows one common trait: while most articles agree that brain networks are usually preserved after SCI, and that is not the case as some articles describe possible alterations in brain activation after the lesion. There is no consensus if those alterations indeed occur. In articles that show alterations, there is no agreement if they are transient or permanent. Besides, there is no consensus on which areas are most prone to activation changes, or on the intensity and direction (increase vs. decrease) of those possible changes. In this article, we present a critical review of the literature and trace possible reasons for those contradictory findings on brain reorganization following SCI. fMRI studies based on the ankle dorsiflexion, upper-limb, and tongue paradigms are used as case studies for the analyses.