The association between isometric strength and cognitive function in adults with cerebral palsy.

Background: The literature supports quantifying the maximum force/tension generated by one's forearm muscles such as the hand grip strength (HGS) to screen for physical and cognitive frailty in older adults. Thus, we postulate that individuals with cerebral palsy (CP), who are at higher risk for premature aging, could benefit from tools that objectively measure muscle strength as a functional biomarker to detect frailty and cognitive decline. This study assesses the clinical relevancy of the former and quantifies isometric muscle strength to determine its association with cognitive function in adults with CP. Methods: Ambulatory adults with CP were identified from a patient registry and were enrolled into this study. Peak rate of force development (RFD) and maximum voluntary isometric contraction of the quadriceps were measured using a commercial isokinetic machine, while HGS was collected with a clinical dynamometer. Dominant and non-dominant side were identified. Standardized cognitive assessments, including the Wechsler Memory and Adult Intelligence Scales IV, Short Test of Mental Status, and the Patient-Reported Outcomes Measurement Information System (PROMIS®) were used to evaluate cognitive function. Results: A total of 57 participants (32 females; mean age 24.3 [SD 5.3]; GMFCS levels I-IV) were included in the analysis. Although dominant and non-dominant RFD and HGS measures were associated with cognitive function, non-dominant peak RFD showed the strongest associations with cognitive function. Conclusion: RFD capacity may reflect age-related neural and physical health and could be a better health indicator than HGS in the CP population.

Associations of Circulating Insulin-Growth Factor-1 With Cognitive Functions and Quality of Life Domains in Ambulatory Young Adults With Cerebral Palsy: A Pilot Study.

Objective: Adults with cerebral palsy (CP) often have impaired cognitive functions. CP also has deteriorations in multiple quality-of-life (QoL) domains. The bio-psycho-social health psychology model posits that biological factor interacts with social and psychological functions. However, the biological determinant of psycho-social and functional outcomes in CP has been scarcely examined. Circulating Insulin-like growth factor-1 (IGF-1) is associated with cognitive deficits in older adults, we thus aimed to examine the associations of circulating IGF-1 with: (1) objectively measured cognitive functions, (2) self-reported cognitive functions, and (3) QoL measures in adults diagnosed with CP. Methods: Seventy-two adults with CP and varying degrees of cognitive functions were recruited from an accredited clinical motion analysis laboratory at a regional Children's Hospital. Circulating IGF-1 was measured using post-fasting serum. The Wechsler Adult Intelligence Scale (WAIS) tests were administered to assess multiple cognitive functions, whereas the Patient-Reported Outcomes Measurement Information System (PROMIS) was used to measure multiple domains of self-reported health, including cognitive complaints and eight QoL domains. Results: Sixty-eight participants had complete data [mean age = 25 (SD = 5.3), female = 52.8%]. Controlling for covariates, circulating IGF-1 was associated with multiple cognitive domains, including positively with declarative memory and executive function and inversely with visual-spatial and motor skills, and processing speed, while no association with subjective memory complaint was detected. Circulating IGF-1 was also inversely associated with four QoL domains, including depressive symptoms, executive function, physical function, and social roles and activities. Conclusions: In CP, circulating IGF-1 might be a useful biological determinant of objective cognitive functions and several quality-of-life domains commonly impaired in CP.

Increased plasma brain-derived neurotrophic factor (BDNF) as a potential biomarker for and compensatory mechanism in mild cognitive impairment: a case-control study.

BACKGROUND: Previous meta-analyses examining the continuum of Alzheimer's disease (AD) concluded significantly decreased peripheral brain-derived neurotrophic factor (BDNF) in AD. However, across different meta-analyses, there remain inconsistent findings on peripheral BDNF levels in individuals with mild cognitive impairment (MCI). This issue has been attributed to the highly heterogenous clinical and laboratory factors. Thus, BDNF's level, discriminative accuracy for identifying all-cause MCI and its subtypes, and its associations with other biomarkers and neurocognitive domains, remain largely unknown. METHODS: To address this heterogeneity, we compared a healthy control cohort (n=56, 45 female) to an MCI cohort (n=40, 28 female), to determine whether plasma BDNF, hs-CRP, and DHEA-S can differentiate healthy from MCI individuals, including two MCI subtypes (amnestic [aMCI] and non-amnestic [non-aMCI]). The associations between BDNF with other biomarkers and neurocognitive tests were examined. Adults with cerebral palsy were included as sensitivity analyses. RESULTS: Compared to healthy controls, BDNF was significantly higher in all-cause MCI, aMCI, and non-aMCI. Furthermore, BDNF had good (AUC=0.84, 95% CI=0.74 to 0.95, p<0.001) and excellent discriminative accuracies (AUC=0.92, 95% CI=0.84 to 1.00, p<0.001) for all-cause MCI and non-amnestic MCI, respectively. BDNF was significantly and positively associated with plasma hs-CRP (ß=0.26, 95% CI=0.02 to 0.50, p=0.038), despite attenuated association upon controlling for BMI (ß=0.15, 95% CI=-0.08 to 0.38, p=0.186). Multiple inverse associations between BDNF and detailed neurocognitive tests were also detected. CONCLUSIONS: These findings suggest BDNF is increased as a compensatory mechanism in preclinical dementia, supporting the neurotrophic and partially the inflammatory hypotheses of cognitive impairment.

Radiographic and plantar pressure assessment of pes planovalgus severity in children with cerebral palsy.

BACKGROUND: Pes planovalgus is common in children with cerebral palsy. Although severity influences treatment, there still lacks standard clinical measurements to objectively quantify pes planovalgus in this population. The comparison of pedobarographic data and radiographic measurements to clinical evaluation has not been reported in this population. METHODS: 395  feet were identified from a population of ambulatory pediatric patients with cerebral palsy. Each patient initially underwent clinical evaluation by an experienced physical therapist who classified feet as: 136 controls, 116 mild, 100 moderate, and 43 severe pes planovalgus. Quantitative measurements were then calculated from antero-posterior and lateral radiographs of the foot. Pedobarographic analysis included the arch index, center of pressure index, and a newly defined medial index. FINDINGS: A multivariate analysis was performed on the radiographic and pedobarographic measurements collected. It identified seven variables that improved objective classification of pes planovalgus severity when utilized together. These include the foot progression angle, initial contact force, arch index, medial index, antero-posterior talonavicular coverage, lateral calcaneal pitch and lateral Meary's angle. While the lateral calcaneal pitch angle statistically differed amongst all severity classes, no pedobarographic value statistically differed between all severity classes. INTERPRETATION: Overall, the combination of radiographic and pedobarographic measurements provides valuable information for objectively classifying severity of pes planovalgus in children with cerebral palsy by utilizing these values together rather than independently. In a clinical setting, radiographs and pedobarographic data may be obtained to enhance assessment of severity and guide treatment.

Commonalities in biomarkers and phenotypes between mild cognitive impairment and cerebral palsy: a pilot exploratory study.

Clinically, individuals with cerebral palsy (CP) experience symptoms of accelerated biological aging. Accumulative deficits in both molecular underpinnings and functions in young adults with CP can lead to premature aging, such as heart disease and mild cognitive impairment (MCI). MCI is an intermediate stage between healthy aging and dementia that normally develops at old age. Owing to their intriguingly parallel yet "inverted" disease trajectories, CP might share similar pathology and phenotypes with MCI, conferring increased risk for developing dementia at a much younger age. Thus, we examined this hypothesis by evaluating these two distinct populations (MCI= 55, CP = 72). A total of nine measures (e.g., blood biomarkers, neurocognition, Framingham Heart Study Score (FHSS) were compared between the groups. Compared to MCI, upon controlling for covariates, delta FHSS, brain-derived neurotrophic factor (BDNF) levels, and systolic blood pressure were significantly lower in CP. Intriguingly, high-sensitivity CRP, several metabolic outcomes, and neurocognitive function were similar between the two groups. This study supports a shared biological underpinning and key phenotypes between CP and MCI. Thus, we proposed a double-hit model for the development of premature aging outcomes in CP through shared biomarkers. Future longitudinal follow-up studies are warranted to examine accelerated biological aging.

Peak sagittal plane spine kinematics in female gymnasts with and without a history of low back pain.

BACKGROUND: Female gymnasts have a greater prevalence of back pain compared to other female athletes. There is little evidence that female artistic gymnasts with and without back pain demonstrate different movement patterns during gymnastics skills. The purpose of this study was to determine if there were differences in back movements during back walkovers and back handsprings among female artistic gymnasts. METHODS: Female artistic gymnasts (8-18 years old) with and without back pain wore inertial sensors on their torso, arms, and legs while performing back walkovers (N = 14) and back handsprings (N = 15) on the floor and balance beam at their training gymnastics facilities. FINDINGS: Gymnasts with back pain had similar spine peak extension, peak flexion, and range of motion during back walkovers and back handsprings compared to gymnasts without back pain. Additionally, no differences in sagittal plane spine kinematics were found between the groups at any specific time point during either the back walkover or back handspring skills. However, a large portion of the data collected was excluded during quality assurance, thus our final sample sizes are small. INTERPRETATION: These findings suggest that gymnasts with back pain have similar sagittal plane movements to those without back pain. The relationship between back pain and gymnastics training load/intensity is currently unclear. We suggest future studies to investigate common artistic gymnastics skills and back pain prevalence with more participants, full-body motion analysis with kinetic measurement capabilities, and longitudinally for those demonstrating back pain.

Self-reported physical function is associated with walking speed in adults with cerebral palsy.

PURPOSE: To understand the relationship of walking speed to self-reported pain, fatigue, and physical function in adults with CP. METHODS: Design: Cross-sectional study. SETTING: Accredited clinical motion analysis laboratory in a regional children's hospital. PARTICIPANTS: 72 ambulatory patients ⩾ 18 years of age, diagnosed with CP, who previously had ⩾ 1 prior instrumented gait analysis at our facility. MAIN OUTCOME MEASURES: PROMIS-57 pain interference/intensity, physical function, and fatigue measures and walking speed. RESULTS: Physical function was significantly lower than able-bodied normal values by 1-2 standard deviations (40.3 ± 8.5). Pain interference (51.4 ± 9.0) and fatigue (50.2 ± 9.2) were not significantly different when compared to able-bodied normal values. Only physical function was statistically correlated with walking speed (p< 0.001), while pain interference (p= 0.39), pain intensity (p= 0.36), and fatigue (p= 0.75) were not. Pain interference, pain intensity, and fatigue were not statistically significant factors in the multiple regression of walking speed. Fatigue could significantly predict physical function, pain interference, and pain scores (p= 0.032, p< 0.001, p< 0.01, respectively), however, fatigue did not directly predict walking speed (p= 0.747). CONCLUSIONS: Self-reported physical function correlates with objectively measured walking speed in young adults with CP while patient-reported pain and fatigue did not, contrary to what would be predicted by the literature.

Prevalence of metabolic syndrome and cardiovascular disease risk factors in adults with cerebral palsy.

AIM: To investigate the prevalence of metabolic syndrome and cardiovascular disease (CVD) risk factors and the association between common metabolic markers and Gross Motor Function Classification System (GMFCS) levels in ambulatory adults with cerebral palsy (CP). METHOD: Metabolic markers and GMFCS levels were evaluated in a cross-sectional study of 70 ambulatory adults with CP (34 males, 36 females; mean age 24y 5mo [SD 5y 4mo], range 18y 6mo-48y 8mo) to determine the prevalence of metabolic syndrome and CVD risk factors, and were compared to age-matched, population norms from the National Health and Nutrition Examination Survey (NHANES) registry. The Framingham Heart Study (FHS) CVD risk estimation was also used to evaluate an individual's risk for CVD. RESULTS: Metabolic syndrome was identified in 17.1% of the cohort, higher than the 10% in the NHANES registry. The FHS CVD 30-year lipid and body mass index (BMI)-based risk factor results showed that 20% to 40% of the cohort was at greater risk of developing CVD (BMI-based: 39.7% 'full' CVD risk factor; lipid-based: 26.5% 'full' CVD risk factor) as compared to the FHS normative population data. There was a positive correlation between GMFCS level, waist circumference (r=0.28, p=0.02), and waist-to-hip ratio (r=0.28, p=0.02). INTERPRETATION: Adults with CP are at higher risk of CVD and metabolic syndrome compared to the general population, which is probably because of impaired mobility.

Relative phase measures of intersegmental coordination describe motor control impairments in children with cerebral palsy who exhibit stiff-knee gait.

BACKGROUND: The purpose of this retrospective study was to explore lower limb intersegmental coordination as a clinically important indicator of motor control mechanisms in individuals with cerebral palsy exhibiting stiff-knee gait. We used the relative phase of thigh and foot segments around foot-off to describe motor control, given the relevance of the pre-swing phase of gait to the existence of stiff-knee gait. METHODS: Traditional gait parameters and thigh/foot intersegmental coordination were calculated using pre-and postoperative kinematic data from a cohort of 54 subjects (92 legs) with spastic cerebral palsy. All participants had stiff-knee gait, walked without assistive devices, and underwent rectus femoris transfer surgery to improve swing period knee flexion. Analyses included correlations between a) preoperative intersegmental coordination and gait variables (knee flexion range, rate and gait performance) and b) pre-to-postoperative intersegmental coordination change and change in gait variables. FINDINGS: Thigh/foot intersegmental coordination significantly (P < 0.001) correlated with knee flexion range, rate and walking speed. Postoperative intersegmental coordination was significantly more uncoupled than preoperative. Pre-to-postoperative intersegmental coordination improvement also significantly correlated with improvements in knee flexion range, rate and walking speed. Pre-to-postoperative changes in intersegmental coordination accounted for 43% and 36% of variance in knee flexion range change and knee flexion rate change respectively. INTERPRETATION: Intersegmental coordination is a clinically important factor in knee flexion limitations associated with stiff-knee gait for individuals with cerebral palsy. These findings are a foundation for further study of intersegmental coordination measures as complements to traditional instrumented gait analysis.

POSTURAL STABILITY AND KINETIC CHANGE IN SUBJECTS WITH PATELLOFEMORAL PAIN AFTER A NINE-WEEK HIP AND CORE STRENGTHENING INTERVENTION.

BACKGROUND: Idiopathic patellofemoral pain (PFP) has been linked to hip weakness and abnormal lower extremity mechanics. The effect of a strengthening intervention on balance has not been well studied among individuals with PFP. HYPOTHESIS/PURPOSE: The primary aim of this study was to evaluate changes in center of pressure displacement during the single limb squat following a nine-week physical therapy intervention among adolescent females with PFP. STUDY DESIGN: Interventional and cross-sectional. METHODS: Seven adolescent females with PFP (10 extremities) were included in the study. Center of Pressure (CoP) excursions during a single limb squat task were measured before and after a nine week of physical therapy intervention focused on strengthening of the hip and core. Seven asymptomatic females were matched to the PFP group on the basis of age and activity level, and were tested as a reference group. CoP trajectories were reduced into four variables: mean distance (MDIST), root-mean-square distance (RDIST), range (RANGE), and 95% confidence interval circle area (AREA-CC). Maximum knee flexion angle, peak knee power generation and absorption were also recorded. Linear mixed models were used to test for within and between group differences in CoP metrics. RESULTS: Pre-intervention, CoP range, knee power absorption and generation were significantly decreased in the PFP group relative to the reference group. Post-intervention, the PFP group reported a significant decrease in symptom severity. There was also a significant (p<0.05) increase in MDIST, RDIST, RANGE, AREA-CC, peak knee flexion angle, peak power absorption and power generation. There was no difference (p>0.05) in knee flexion, knee power or CoP displacement between the two groups after the physical therapy intervention. CONCLUSION: Hip and core-strengthening resulted in a significant decrease in symptom severity as well as significant reductions in CoP displacement. LEVEL OF EVIDENCE: 3.

Analysis of Reach-to-Grasp by School-Aged Children with Down Syndrome Elucidates Limitations in Upper Extremity Motor Control.

AIMS: To identify limitations in preparatory planning (PP) and movement execution that constrain performance of reach-to-grasp (RTG) movements in school-aged children with Down syndrome (DS) and examine the effect of chronological age (CA) on performance. METHODS: Nine children with DS ages 6 to 12 years and nine with typical development (TD) participated in this pilot descriptive study. Three-dimensional kinematic analysis was applied to RTG movements performed in the context of two functional tasks. RESULTS: PP variables focused on the coordination of reach and grasp. Compared to the group with TD, the group with DS demonstrated significant limitations in anticipatory slowing down of hand transport and orientation of the hand in preparation for object contact. There was also relatively late onset of preparatory grip formation in the group with DS. In regard to movement execution, reach trajectories of the group with DS showed significantly greater deviation from the straight path. Correlations of study variables with CA were low and insignificant in both groups. CONCLUSIONS: Motor control mechanisms that mediate both PP and execution of the fundamental RTG movement are potential factors limiting upper extremity activity in school-aged children with DS. They should be addressed in future intervention-based research.

Sagittal plane coordination dynamics of typically developing gait.

BACKGROUND: Individuals who undergo an instrumented gait analysis often have an aberrant gait pattern due to neuromuscular impairments that adversely affect their coordination. Conventional instrumented gait analysis descriptors fail to capture the complex coordination dynamics of gait. This paper presents a straightforward methodology for generating descriptors of coordination dynamics based on dynamical systems theory and provides the largest reported dataset of sagittal plane coordination measures, including adjacent and non-adjacent segment pairings, from individuals free of gait pathology walking over-ground. METHODS: Tri-planar marker trajectories from 104 unimpaired subjects between the ages of 8 and 66 years were collected as they walked at a self-selected speed on a level surface. Phase portraits for the pelvis, thigh, shank, and foot and continuous relative phase diagrams for the segment pairs of pelvis-thigh, thigh-shank, shank-foot, and thigh-foot were calculated. FINDINGS: The low coefficients of variation for each coordination curve are comparable to inter-subject coefficients of variation for kinematic curves, narrow confidence intervals for relative phase angles at four essential footfall conditions, and small standard deviation bands of the continuous relative phase diagrams are evidence that these curves characterize the coordination dynamics of normal gait. INTERPRETATION: These findings support the use of this normative dataset as a reference for coordination studies in the clinic or research laboratory. Improving our understanding of gait strategies from the level of coordination and characterizing the natural variability in gait patterns offer a means to enhance our understanding of atypical gait patterns.

The role of gait analysis in treating gait abnormalities in cerebral palsy.

Individuals with cerebral palsy (CP) cannot take a normal activity like walking for granted. CP is the most common pediatric neurologic disorder, with an incidence of 3.6 per 1000 live births. The current trend in the treatment of individuals with CP is to perform a thorough evaluation including a complete patient history from birth to present, a comprehensive physical examination, appropriate radiographs, consultation with other medical specialists, and analysis of gait.

Rectus femoris transfer in children with cerebral palsy: evaluation of transfer site and preoperative indicators.

BACKGROUND: Rectus femoris transfer (RFT) is a treatment option for children with cerebral palsy (CP) who exhibit a stiff-knee gait pattern. The rectus femoris muscle is transferred to different sites to overcome problems such as tripping and falling. Indications for RFT often include preoperative decreased knee range of motion (KROM) during swing phase, reduced peak knee flexion in swing (PKFSW), abnormal rectus femoris firing patterns on electromyography recordings, and a positive Duncan-Ely test. This study investigated the effect of different RFT sites on kinematic outcome variables and evaluated the relationship between commonly used preoperative surgical indicators and postoperative changes in kinematics. METHODS: Thirty-eight patients with CP, who underwent RFT, with preoperative and postoperative instrumented gait analyses, were evaluated and divided by transfer site: semitendinosus, sartorius, and gracilis. Preoperative and postoperative comparisons were made for 5 knee kinematic variables: range of motion (KROM), peak flexion at loading response, peak extension at terminal stance, PKFSW, and peak extension at terminal swing. Analysis was performed in accordance to different transfer sites and overall postoperative change. RESULTS: When all limbs were analyzed together for the 5 outcome variables, it was found that patients experienced significant (P < 0.05) improvements in sagittal-plane kinematics in 3 of the outcome variables: KROM, PKFSW, and peak extension at terminal swing. Patients had a significant improvement in postoperative KROM when the preoperative KROM was less than 80% of normal. Electromyography pattern and Duncan-Ely test were not found to be useful indicators of surgical success. CONCLUSION: The authors recommend RFT in children with CP who exhibit a stiff-knee gait, regardless of transfer site. LEVEL OF EVIDENCE: Level 3.

Effectiveness of instrumented gait analysis in children with cerebral palsy--comparison of outcomes.

The aim of this study was to evaluate the impact of instrumented gait analysis on the walking performance of children with cerebral palsy at The Children's Hospital, Denver. The study population consisted of 2 groups of 10 children; an experimental group (X) and a recommendation matched control group (C). All subjects had 2 instrumented gait analyses at least 1 year apart. Group X was composed of patients who abided by the gait analysis recommendations and completed all surgical interventions. Group C included patients who chose not to follow surgical recommendations from the initial gait analysis but instead pursued alternative nonsurgical treatments. Sagittal and coronal plane kinematic outcomes for each surgical procedure were obtained from comparing sequential instrumented gait analyses, and analyzed using logistic regression. Group X was found to experience a significantly higher percentage of positive outcomes (44%) than Group C (26%). The calculated odds ratio using the Wald test indicated that patients who complied with gait analysis surgical recommendations were 3.68 times more likely to experience a positive outcome than recommendation matched patients who chose not to follow gait analysis recommendations.

Strategies for clinical motion analysis based on functional decomposition of the gait cycle.

In this article the authors have developed a strategy for clinical gait analysis that takes advantage of the functional subdivisions that naturally occur during the gait cycle. By organizing the contributions of several investigators, the authors have identified the important critical events that must occur during each phase of gait and related those features to specific gait measurements that are routinely available from modern motion analysis laboratories. In addition, the authors have provided examples of how findings from a motion laboratory can be used to suggest possible interventions that can improve or restore absent or abnormal critical events, thereby improving the overall gait performance of the patient with gait pathology. While this condensed version of motion analysis strategies is not sufficiently comprehensive to address all individuals who have gait pathology, the authors hope that it serves as a suitable introduction to this challenging field.

Gait initiation in community-dwelling adults with Parkinson disease: comparison with older and younger adults without the disease.

BACKGROUND AND PURPOSE: Initiation of gait requires transitions from relatively stationary positions to stability with movement and from double- to single-limb stances. These are deliberately destabilizing activities that may be difficult for people with early Parkinson disease (PD), even when they have no problems with level walking. We studied differences in postural stability during gait initiation between participants with early and middle stages of PD (characterized by Hoehn and Yahr as stages 1-3) and 2 other groups of participants without PD--older and younger adults. SUBJECTS: The mean ages of the 3 groups of participants were as follows: subjects with PD, 69.3 years (SD=5.7, range=59-78); older subjects without PD, 69.0 years (SD=3.9, range=65-79); and younger subjects without PD, 27.5 (SD=3.9, range=22-35). METHODS: A 3-dimensional motion analysis system was used with 2 force platforms to obtain data for center of mass (COM) and center of pressure (COP). The distance between the vertical projections of the COM and the COP (COM-COP distance) was used to reflect postural control during 5 events in gait initiation. RESULTS: By use of multivariate analysis of variance, differences in COM-COP distance were found among the 3 groups. An analysis of variance indicated differences for 4 of the 5 events in gait initiation. A Scheffe post hoc analysis demonstrated differences in gait initiation between the subjects with PD and both groups of subjects without PD (2 events) and between the subjects with PD and the younger subjects without PD (2 events). DISCUSSION AND CONCLUSION: The COM-COP distance relationship was used to measure postural control during the transition from quiet standing to steady-state gait. Differences between groups indicated that individuals with impaired postural control allow less COM-COP distance than do individuals with no known neurologic problems. The method used could prove useful in the development and assessment of interventions to improve ambulation safety and enhance the independence of people with impaired postural control.