Movement Scales Research Articles

Closed-Loop Wearable Device Network of Intrinsically-Controlled, Bilateral Coordinated Functional Electrical Stimulation for Stroke.

Innovative functional electrical stimulation has demonstrated effectiveness in enhancing daily walking and rehabilitating stroke patients with foot drop. However, its lack of precision in stimulating timing, individual adaptivity, and bilateral symmetry, resulted in diminished clinical efficacy. Therefore, a closed-loop wearable device network of intrinsically controlled functional electrical stimulation (CI-FES) system is proposed, which utilizes the personal surface myoelectricity, derived from the intrinsic neuro signal, as the switch to activate/deactivate the stimulation on the affected side. Simultaneously, it decodes the myoelectricity signal of the patient's healthy side to adjust the stimulation intensity, forming an intrinsically controlled loop with the inertial measurement units. With CI-FES assistance, patients' walking ability significantly improved, evidenced by the shift in ankle joint angle mean and variance from 105.53° and 28.84 to 102.81° and 17.71, and the oxyhemoglobin concentration tested by the functional near-infrared spectroscopy. In long-term CI-FES-assisted clinical testing, the discriminability in machine learning classification between patients and healthy individuals gradually decreased from 100% to 92.5%, suggesting a remarkable recovery tendency, further substantiated by performance on the functional movement scales. The developed CI-FES system is crucial for contralateral-hemiplegic stroke recovery, paving the way for future closed-loop stimulation systems in stroke rehabilitation is anticipated.

Factor analysis and validation of the Bush Francis catatonia rating scale-Spain version

Background and objectivesThe aim of this study was to assess the reliability and validity of the Bush Francis Catatonia Screening Instrument and Bush Francis Catatonia Rating Scale Spain Version (BFCSI-SV and BFCRS-SV) using the ICD-11 and DSM-5 diagnostic criteria as well as other catatonia scales. MethodsOne hundred patients were admitted to the inpatient psychiatry unit at Hospital Universitari Germans Trias I Pujol and two psychiatrists administered the BFCRS-SV to the first 10 patients to assess inter-rater reliability. The BFCRS-SV, BFCSI-SV, Modified Rogers Scale (MRS), Abnormal Involuntary Movement Scales, Barnes Akathisia Rating Scale, and Modified Simpson-Angus Scale were then employed. ResultsThe results showed that 27% of patients had catatonia using the DSM-5 diagnostic criteria. Additionally, 51% of patients had 2 or more BFCRSI-SV items (Sensitivity: 100%; Specificity: 67.12%). The alpha coefficient values were 0.80 and 0.84 for the BFCSI-SV and BFCRS-SV, respectively, and the intraclass correlation coefficient values were 0.902 and 0.903. The area under the ROC curve was 0.971 and 0.96, and the instruments had a strong positive correlation with the DSM-5 score, ICD-11 score, and MRS. The study identified a three-factor model comprising the inhibition, excitement, and parakinetic dimensions. ConclusionsOverall, the results suggest that the BFCSI-SV and BFCRS-SV are valid and reliable tools for the diagnosis of catatonia, especially when using a cut-off score of 5 or higher for the BFCSI-SV and 7 or higher for the BFCRS-SV.

Use of eye tracking to improve the identification of attention-deficit/hyperactivity disorder in children

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder of childhood. Although it requires timely detection and intervention, existing continuous performance tests (CPTs) have limited efficacy. Research suggests that eye movement could offer important diagnostic information for ADHD. This study aimed to compare the performance of eye-tracking with that of CPTs, both alone and in combination, and to evaluate the effect of medication on eye movement and CPT outcomes. We recruited participants into an ADHD group and a healthy control group between July 2021 and March 2022 from among children aged 6–10 years (n = 30 per group). The integration of eye-tracking with CPTs produced higher values for the area under the receiver operating characteristic (AUC, 0.889) compared with using CPTs only (AUC, 0.769) for identifying patients with ADHD. The use of eye-tracking alone showed higher performance compare with the use of CPTs alone (AUC of EYE: 0.856, AUC of CPT: 0.769, p = 0.029). Follow-up analysis revealed that most eye-tracking and CPT indicators improved significantly after taking an ADHD medication. The use of eye movement scales could be used to differentiate children with ADHD, with the possibility that integrating eye movement scales and CPTs could improve diagnostic precision.

Establishing a natural history of X-linked dystonia parkinsonism.

X-linked dystonia parkinsonism is a neurodegenerative movement disorder that affects men whose mothers originate from the island of Panay, Philippines. Current evidence indicates that the most likely cause is an expansion in the TAF1 gene that may be amenable to treatment. To prepare for clinical trials of therapeutic candidates for X-linked dystonia parkinsonism, we focused on the identification of quantitative phenotypic measures that are most strongly associated with disease progression. Our main objective is to establish a comprehensive, quantitative assessment of movement dysfunction and bulbar motor impairments that are sensitive and specific to disease progression in persons with X-linked dystonia parkinsonism. These measures will set the stage for future treatment trials. We enrolled patients with X-linked dystonia parkinsonism and performed a comprehensive oromotor, speech and neurological assessment. Measurements included patient-reported questionnaires regarding daily living activities and both neurologist-rated movement scales and objective quantitative measures of bulbar function and nutritional status. Patients were followed for 18 months from the date of enrollment and evaluated every 6 months during that period. We analysed a total of 87 men: 29 were gene-positive and had symptoms at enrollment, seven were gene-positive and had no symptoms at enrollment and 51 were gene-negative. We identified measures that displayed a significant change over the study. We used principal variables analysis to identify a minimal battery of 21 measures that explains 67.3% of the variance over the course of the study. These measures included patient-reported, clinician-rated and objective quantitative outcomes that may serve as endpoints in future clinical trials.

Evaluating the prevalence and spatial distribution of giraffes injured by non‐target poaching

AbstractIllegal harvest (poaching) is a geographically widespread threat to animal populations. Wire snares are a common poaching technique used in the Global South and are indiscriminate with respect to species, age, and sex of individual animals that they capture. When caught, relatively large mammals frequently break free from the snares, suffering injuries in the process. The prevalence of snaring injuries as well as the ecological and conservation implications of such patterns have not been widely investigated for many animal populations. We evaluated the prevalence and spatial distribution of giraffes (Giraffa camelopardalis) with snaring injuries in Murchison Falls National Park, Uganda, a system experiencing high rates of wire snare poaching. We conducted photographic spatial encounter surveys along five fixed road transects. We photographed detected giraffes, recorded whether a snaring injury was present, and identified individuals via autonomous image processing of pelage patterns. We fitted a spatial capture‐recapture (SCR) model to the encounter history data to estimate abundance and predict the spatial distribution of injured giraffes. We detected 1306 (sub) adult giraffes from the surveys and predicted 1939 (±80) via the SCR model. We encountered 26 giraffes with snaring injuries, corresponding to a population‐level snaring rate of 1.4%. Individuals with higher movement scales were more at risk of being snared. Though not fatal across the three‐month duration of this study, the injuries likely lead to secondary infections, disability, and potentially death in the long term. We explore the implications of bearing snaring injuries for ecology, behavior, and conservation of affected species.

Testing angular velocity as a new metric for metabolic demands of slow-moving marine fauna: a case study with Giant spider conchs Lambis truncata

BackgroundQuantifying metabolic rate in free-living animals is invaluable in understanding the costs of behaviour and movement for individuals and communities. Dynamic body acceleration (DBA) metrics, such as vectoral DBA (VeDBA), are commonly used as proxies for the energy expenditure of movement but are of limited applicability for slow-moving species. It has recently been suggested that metrics based on angular velocity might be better suited to characterise their energetics. We investigated whether a novel metric—the ‘Rate of change of Rotational Movement (RocRM)’, calculated from the vectoral sum of change in the pitch, roll and yaw/heading axes over a given length of time, is a suitable proxy for energy expenditure.ResultsWe found that RocRM can be used as an alternative energy expenditure proxy in a slow-moving benthic invertebrate. Eleven Giant spider conchs Lambis truncata (collected in the Red Sea) were instrumented with multiple channel (Daily Diary) tags and kept in sealed chambers for 5 h while their oxygen consumption, V̇O2, was measured. We found RocRM to be positively correlated with V̇O2, this relationship being affected by the time-step (i.e. the range of the calculated differential) of the RocRM. Time steps of 1, 5, 10 and 60 s yielded an explained variability of between 15 and 31%. The relationship between V̇O2 and VeDBA was not statistically significant, suggesting RocRM to provide more accurate estimations of metabolic rates in L. truncata.ConclusionsRocRM proved to be a statistically significant predictor of V̇O2 where VeDBA did not, validating the approach of using angular-based metrics over dynamic movement-based ones for slower moving animals. Further work is required to validate the use of RocRM for other species, particularly in animals with minimally dynamic movement, to better understand energetic costs of whole ecosystems. Unexplained variability in the models might be a consequence of the methodology used, but also likely a result of conch activity that does not manifest in movement of the shell. Additionally, density plots of mean RocRM at each time-step suggest differences in movement scales, which may collectively be useful as a species fingerprint of movement going forward.

GIS modeling of lithic procurement in highlands: Archaeological and actualistic approach in the Andes

The purpose of this work is to model human movements and lithic procurement costs in high-altitude environments on the basis of geographical aspects. Using GIS we analyzed movement costs that can be applied as of early occupation times in the Southern Andes. We compared curves used to analyze pedestrian movements and contrasted actualistic and ethnographic information in the Andes. We adapted the Tobler Offpath Hiking algorithm to GIS and estimated movement costs in the process of exploiting lithic resources that can be considered within local, non-local and extra-regional categories in Andean topographies as a function of isochrons or times of movement. We propose “local” to be the range of space which can be accessed in one 8-hour movement day. On this scale we establish a ranking regarding the costs of accessing the sources of raw material. The resulting movement scales can be useful for works in comparable environments and in different stages of occupation of high-altitude spaces.

Safety and Effectiveness of SEP−363856 in Schizophrenia: Results of a 6-Month, Open-Label Extension Study

SEP-363856 is a novel psychotropic agent without dopamine D2 receptor occupancy. Although its mechanism of action has not been fully elucidated, preclinical data suggest that agonism at trace amine receptor 1 (TAAR1) and the serotonin 5-H1A receptor contributes to its efficacy. In a double-blind (DB), placebo-controlled study, SEP-363856 demonstrated significant efficacy in the treatment of an exacerbation of schizophrenia (Koblan et al, NEJM 2020; 82:1497-1506). We present results of a 6-month extension study whose aim was to evaluate the safety and effectiveness of longer-term treatment with SEP-363856. Patients with an acute exacerbation of schizophrenia who completed a 4-week, DB, placebo-controlled, flexible-dose (50 or 75 mg) study of SEP-363856 were given the option to enroll in an extension study in which they were treated, open-label (OL), with flexible doses (25/50/75 mg/d) of SEP-363856 for 26-weeks. The primary outcomes were safety measures; effectiveness outcomes were secondary and included the PANSS total score and the Brief Negative Symptom Scale (BNSS) total score. A total of 193 patients completed the 4-week DB study, and 156 (80.8%) were dosed in the OL extension study and received at least one dose of SEP-363856 (safety population). Study completer rate was 66.9%; reasons for discontinuation consisted of adverse event (11.5%), withdrawal of consent (10.2%), lack of efficacy (5.1%), and other (6.4%). 15 patients experienced an SAE: schizophrenia (n=11); acute psychosis (N=1); uterine hemorrhage and suicidal ideation (N=1 each); there were no deaths in the study. Individual AEs with an incidence =2% were schizophrenia (12.2%), headache (11.5%), insomnia (8.3%), anxiety (5.1%), somnolence (4.5%), nasopharyngitis (4.5%), nausea (3.8%), irritability (3.2%), influenza (3.2%), weight decreased (3.2%), and prolactin increased (2.6%). On movement scales, minimal mean change from OL-baseline to Week 26 occurred on the Barnes total score (-0.1), AIMS total score (0.0) and SAS score (-0.1). Mean month 6 change from DB baseline in weight was -0.3 kg. No clinically meaningful median changes were observed at week 26 in metabolic laboratory parameters (total and LDL cholesterol, triglycerides, hemoglobin A1c) or in prolactin levels. During 6 months of OL treatment, one patient had an increase in QTcF =60 msec; no patients had a QTcF interval =480 msec. Treatment with SEP-363856 was associated with significant improvement from OL baseline to week 26 in PANSS total score (-22.6) and BNSS total score (-11.3). Treatment with SEP-363856 was associated with continued improvement from open-label baseline in the PANSS total (-22.6) and BNSS total (-11.3) scores. The most frequently reported adverse events (= 5%) were schizophrenia, headache, insomnia and anxiety. SEP-363856 had minimal effects on weight, lipids, glycemic indices, prolactin, and was associated with minimal risk of extrapyramidal symptom. Sunovion Pharmaceuticals Inc.

Similar Long-Term Clinical Outcomes of Deep Brain Stimulation With Different Electrode Targets for Primary Meige Syndrome: One Institution’s Experience of 17 Cases

ObjectiveDeep brain stimulation (DBS) is considered an effective and safe treatment for patients with primary Meige syndrome (MS). Both the subthalamic nucleus (STN) and globus pallidus pars internus (Gpi) have been shown to be optional targets for electrode implantation to improve clinical symptoms, but the relationship between clinical outcomes and target is still unclear. The current study aims to compare the clinical outcomes of DBS with different electrode targets for primary MS. Materials and MethodsWe performed a retrospective study to assess the clinical outcomes for 17 consecutive patients with primary MS in Wuhan Union Hospital from January 2016 to September 2019. Six patients were treated by Gpi-DBS and 11 patients were treated by STN-DBS. All patients were assessed before surgery and at the last follow-up after surgery. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) including the movement and disability scales was used to evaluate the dystonia severity of the eyes, the mouth, speech, and swallowing. The median follow-up duration was 30.1 ± 13.1 months (range 6 months–52 months). ResultsIn our study, DBS improved the BFMDRS-M scores by 70.52 ± 7.45% and the BFMDRS-D scores by 70.51 ± 8.38% for patients with MS. STN-DBS and Gpi-DBS had similar effects not only on the BFMDRS-M and BFMDRS-D scores, but also on the subitems including eyes, mouth, speech, and swallowing. The stimulation voltage for the Gpi was significantly higher than that for the STN. The improvements were similar in the general anesthesia and local anesthesia groups (p > 0.05). ConclusionThe curative effects of STN-DBS and Gpi-DBS on patients with primary MS are similar. Both the STN and Gpi could be effective targets of DBS for primary MS.

Physiological movement disorder-like features during typical motor development.

To compare physiological age-relatedness between dyskinesia (dystonia/choreoathetosis), dystonia and ataxia rating scale scores in healthy children. Three movement disorders specialists quantified dyskinetic-like features in healthy children (n=52; 4-16 years) using the Dyskinesia Impairment Scale (DIS=DIS-choreoathetosis (DIS-C)+DIS-dystonia (DIS-D)). We compared the age-related regression coefficients of the DIS with data processed from previous studies on dystonia and ataxia rating scales (Burke-Fahn-Marsden Movement and Disability Scales (BFMMS and BFMDS) and Scale for Assessment and Rating of Ataxia (SARA), International Cooperative Ataxia Rating Scale (ICARS) and Brief Ataxia Rating Scale (BARS)). Dyskinetic scores were obtained in 79% (DIS); 65% (DIS-D) and 17% (DIS-C) versus dystonic and ataxic scores in 98% (BFMMS) and 89% (SARA/ICARS/BARS) of the children. Age-related DIS and DIS-D scores (B=-0.90 and 0.77; p<0.001) were correlated with age-related BFMMS scores (B=-0.49; p<0.001; r=0.87; p<0.001), whereas DIS-C scores were age-independent. Ataxic scores revealed stronger age-related regression coefficients than dyskinetic and dystonic scores (4-8 years; p<0.05). In healthy children, comparison between physiological dyskinesia, dystonia and ataxia rating scale scores revealed: 1. inverse age-relatedness for dystonic and ataxic scores, but not for choreoathetotic scores, 2. interrelated dystonic DIS-D and BFMMS scores, 3. the strongest age-related expression by ataxic scores. In healthy children, these physiological movement disorder-like features are interpreted as an expression of the developing underlying motor centres.

Post-stroke rehabilitation training with a brain-computer interface: a clinical and neuropsychological study

To evaluate the clinical efficacy of BCI-supported mental practice and to reveal specific cognitive impairment which determine mental practice ineffectiveness and inability to perform MI. Fifty-five hemiplegic patients after first-time stroke (median age 54. 0 [44.0; 61.0], time from onset 6.0 [3.0; 13.0] month) were randomized into two groups - BCI and sham-controlled. Severity of arm paresis was measured by Fugl-Meyer Assessment of Motor Recovery after Stroke (FMA) and Action Research Arm Test (ARAT). Twelve patients from the BCI group were examined using neuropsychological testing. After assessment, patients were trained to imagine kinesthetically a movement under control of BCI with the feedback presented via an exoskeleton. Patients underwent 12 training sessions lasting up to 30 min. In the end of the study, the scores on movement scales, electroencephalographic results obtained during training sessions were analyzed and compared to the results of neuropsychological testing. Evaluation of the UL clinical assessments indicated that both groups improved on ARAT and FMA (sections A-D, H, I) but only the BCI group showed an improvement in the ARAT's grasp score (p=0.012), pinch score (p=0.012), gross movement score (p=0,002). The significant correlation was revealed between particular neuropsychological tests (Taylor Figure test, choice reaction test, Head test) and online accuracy rate. These results suggest that adding BCI control to exoskeleton-assisted physical therapy can improve post-stroke rehabilitation outcomes. Neuropsychological testing can be used for screening before mental practice admission and promote personalized rehabilitation.

Passive elongation of muscle fascicles in human muscles with short and long tendons.

This study tested the hypothesis that the ratio of changes in muscle fascicle and tendon length that occurs with joint movement scales linearly with the ratio of the slack lengths of the muscle fascicles and tendons. We compared the contribution of muscle fascicles to passive muscle‐tendon lengthening in muscles with relatively short and long fascicles. Fifteen healthy adults participated in the study. The medial gastrocnemius, tibialis anterior, and brachialis muscle‐tendon units were passively lengthened by slowly rotating the ankle or elbow. Change in muscle fascicle length was measured with ultrasonography. Change in muscle‐tendon length was calculated from estimated muscle moment arms. Change in tendon length was calculated by subtracting change in fascicle length from change in muscle‐tendon length. The median (IQR) contribution of muscle fascicles to passive lengthening of the muscle‐tendon unit, measured as the ratio of the change in fascicle length to the change in muscle‐tendon unit length, was 0.39 (0.26–0.48) for the medial gastrocnemius, 0.51 (0.29–0.60) for tibialis anterior, and 0.65 (0.49–0.90) for brachialis. Brachialis muscle fascicles contributed to muscle‐tendon unit lengthening significantly more than medial gastrocnemius muscle fascicles, but less than would be expected if the fascicle contribution scaled linearly with the ratio of muscle fascicle and tendon slack lengths.

Quantity of Movement as a Measure of Engagement for Dementia: The Influence of Motivational Disorders.

Engagement in activities is crucial to improve quality of life in dementia. Yet, its measurement relies exclusively on behavior observation and the influence that behavioral and psychological symptoms of dementia (BPSD) have on it is overlooked. This study investigated whether quantity of movement, gauged with a wrist-worn accelerometer, could be a sound measure of engagement and whether apathy and depression negatively affected engagement. Fourteen participants with dementia took part in 6 sessions of activities: 3 of cognitive games (eg, jigsaw puzzles) and 3 of robot play (Pleo). Results highlighted significant correlations between quantity of movement and observational scales of engagement and a strong negative influence of apathy and depression on engagement. Overall, these findings suggest that quantity of movement could be used as an ancillary measure of engagement and underline the need to profile people with dementia according to their concurrent BPSD to better understand their engagement in activities.

Differences in neural pathways are related to the short- or long-term benefits of constraint-induced movement therapy in patients with chronic stroke and hemiparesis: a pilot cohort study

BackgroundNo previous studies have determined how the post-stroke integrity of non-corticospinal neural pathways relates to the efficacy of constraint-induced movement therapy (CIMT).ObjectivesWe aimed to clarify the relationship between several non-corticospinal neural pathway integrities and the short- and long-term benefits of CIMT.MethodsThis was a pilot cohort study (UMIN registration number: R00027136UMIN000023566), for which we enrolled 13 patients with chronic stroke and hemiparesis who had undergone CIMT. We assessed patients’ motor function improvement by comparing the Fugl-Meyer Assessment (FMA) scores, as well as the Amount of Use (AOU) and Quality of Movement (QOM) scales of the Motor Activity Log before, immediately after (short-term), and 6 months after (long-term) CIMT. We assessed neural pathway integrity by calculating fractional anisotropy (FA) in diffusion tensor images acquired before CIMT. We then assessed correlations between FA and short- and long-term post-CIMT motor function improvements.ResultsThe patients showed significant improvements in all functional assessments at both short- and long-term follow-ups. Immediate FMA score improvements were significantly correlated with FA of the affected anterior limb of the internal capsule (ALIC), body of the corpus callosum, column and body of the fornix (CBF), cingulate cortex (CgC), cerebral peduncle (CP), and posterior limb of the internal capsule. Six-month FMA score improvements were significantly correlated with FA of the affected ALIC, CgC, CBF, CP, and superior frontooccipital fasciculus.ConclusionsThe integrity of the affected corticospinal and non-corticospinal motor pathways was associated with CIMT-induced motor learning at least 6 months after CIMT.

Do Irish Adolescents Have Adequate Functional Movement Skill and Confidence?

Recent research has shown that post-primary Irish youth are insufficiently active and fail to reach a level of proficiency across basic fundamental movement skills. The purpose of the current research was to gather cross-sectional data on adolescent youth, differentiated by gender, specifically to inform the development of a targeted movement-oriented intervention. Data were collected on adolescents (N = 219; mean age : 14.45 ± 0.96 years), within two, mixed-gender schools. Data collection included actual and perceived movement measurements comprised of fundamental movement skills, the functional movement screen, perceived movement confidence, and perceived functional confidence. Overall, levels of actual mastery within fundamental and functional movement were low, with significant gender differences observed. Adolescent males scored higher in the overall fundamental movement skill domain (male mean score = 70.87 ± 7.05; female mean score = 65.53 ± 7.13), yet lower within the functional movement screen (male mean score = 13.58 ± 2.59), in comparison to their female counterparts (female mean score = 14.70 ± 2.16). There were high levels of perceived confidence reported within fundamental and functional movement scales. Future intervention strategies should combat the low levels of actual movement skill proficiency, while identifying the reasons for higher perceived movement confidence within adolescents.

Allometric and temporal scaling of movement characteristics in Galapagos tortoises.

Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs. We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour - giant Galapagos tortoises (Chelonoidis spp.) - to test how movement metrics estimated on a monthly basis scaled with body size. We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex. Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates. Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one-dimensional scaling of movement, but also generates valuable insights into the movement ecology of iconic yet poorly understood Galapagos giant tortoises.

The Burke-Fahn-Marsden Dystonia Rating Scale is Age-Dependent in Healthy Children.

The Burke-Fahn-Marsden Dystonia Rating Scale is a universally applied instrument for the quantitative assessment of dystonia in both children and adults. However, immature movements by healthy young children may also show "dystonic characteristics" as a consequence of physiologically incomplete brain maturation. This could implicate that Burke-Fahn-Marsden scale scores are confounded by pediatric age. In healthy young children, we aimed to determine whether physiologically immature movements and postures can induce an age-related effect on Burke-Fahn-Marsden movement and disability scale scores. Nine assessors specializied in movement disorders (3 adult neurologists, 3 pediatric neurologists, and 3 MD/PhD students) independently scored the Burke-Fahn-Marsden movement scale in 52 healthy children (4-16 years of age; 2 boys and 2 girls per year of age). Independent of that, parents scored their children's functional motor development according to the Burke-Fahn-Marsden disability scale in another 52 healthy children (4-16 years of age; 2 boys and 2 girls per year of age). By regression analysis, we determined the association between Burke-Fahn-Marsden movement and disability scales outcomes and pediatric age. In healthy children, assessment of physiologically immature motor performances by the Burke-Fahn-Marsden movement and disability scales showed an association between the outcomes of both scales and age (until 16 years and 12 years of age, β = -0.72 and β = -0.60, for Burke-Fahn-Marsden movement and disability scale, respectively [both P < 0.001]). The Burke-Fahn-Marsden movement and disability scales are influenced by the age of the child. For accurate interpretation of longitudinal Burke-Fahn-Marsden Dystonia Rating Scale scores in young dystonic children, consideration of pediatric age-relatedness appears advisory.

Head Motion and Inattention/Hyperactivity Share Common Genetic Influences: Implications for fMRI Studies of ADHD.

Head motion (HM) is a well known confound in analyses of functional MRI (fMRI) data. Neuroimaging researchers therefore typically treat HM as a nuisance covariate in their analyses. Even so, it is possible that HM shares a common genetic influence with the trait of interest. Here we investigate the extent to which this relationship is due to shared genetic factors, using HM extracted from resting-state fMRI and maternal and self report measures of Inattention and Hyperactivity-Impulsivity from the Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour (SWAN) scales. Our sample consisted of healthy young adult twins (N = 627 (63% females) including 95 MZ and 144 DZ twin pairs, mean age 22, who had mother-reported SWAN; N = 725 (58% females) including 101 MZ and 156 DZ pairs, mean age 25, with self reported SWAN). This design enabled us to distinguish genetic from environmental factors in the association between head movement and ADHD scales. HM was moderately correlated with maternal reports of Inattention (r = 0.17, p-value = 7.4E-5) and Hyperactivity-Impulsivity (r = 0.16, p-value = 2.9E-4), and these associations were mainly due to pleiotropic genetic factors with genetic correlations [95% CIs] of rg = 0.24 [0.02, 0.43] and rg = 0.23 [0.07, 0.39]. Correlations between self-reports and HM were not significant, due largely to increased measurement error. These results indicate that treating HM as a nuisance covariate in neuroimaging studies of ADHD will likely reduce power to detect between-group effects, as the implicit assumption of independence between HM and Inattention or Hyperactivity-Impulsivity is not warranted. The implications of this finding are problematic for fMRI studies of ADHD, as failing to apply HM correction is known to increase the likelihood of false positives. We discuss two ways to circumvent this problem: censoring the motion contaminated frames of the RS-fMRI scan or explicitly modeling the relationship between HM and Inattention or Hyperactivity-Impulsivity.

Phase transitions in optimal search times: How random walkers should combine resetting and flight scales.

Recent works have explored the properties of Lévy flights with resetting in one-dimensional domains and have reported the existence of phase transitions in the phase space of parameters which minimizes the mean first passage time (MFPT) through the origin [L. Kusmierz et al., Phys. Rev. Lett. 113, 220602 (2014)]. Here, we show how actually an interesting dynamics, including also phase transitions for the minimization of the MFPT, can also be obtained without invoking the use of Lévy statistics but for the simpler case of random walks with exponentially distributed flights of constant speed. We explore this dynamics both in the case of finite and infinite domains, and for different implementations of the resetting mechanism to show that different ways to introduce resetting consistently lead to a quite similar dynamics. The use of exponential flights has the strong advantage that exact solutions can be obtained easily for the MFPT through the origin, so a complete analytical characterization of the system dynamics can be provided. Furthermore, we discuss in detail how the phase transitions observed in random walks with resetting are closely related to several ideas recurrently used in the field of random search theory, in particular, to other mechanisms proposed to understand random search in space as mortal random walks or multiscale random walks. As a whole, we corroborate that one of the essential ingredients behind MFPT minimization lies in the combination of multiple movement scales (regardless of their specific origin).

First-passage times in multiscale random walks: The impact of movement scales on search efficiency.

An efficient searcher needs to balance properly the trade-off between the exploration of new spatial areas and the exploitation of nearby resources, an idea which is at the core of scale-free Lévy search strategies. Here we study multiscale random walks as an approximation to the scale-free case and derive the exact expressions for their mean-first-passage times in a one-dimensional finite domain. This allows us to provide a complete analytical description of the dynamics driving the situation in which both nearby and faraway targets are available to the searcher, so the exploration-exploitation trade-off does not have a trivial solution. For this situation, we prove that the combination of only two movement scales is able to outperform both ballistic and Lévy strategies. This two-scale strategy involves an optimal discrimination between the nearby and faraway targets which is only possible by adjusting the range of values of the two movement scales to the typical distances between encounters. So, this optimization necessarily requires some prior information (albeit crude) about target distances or distributions. Furthermore, we found that the incorporation of additional (three, four, …) movement scales and its adjustment to target distances does not improve further the search efficiency. This allows us to claim that optimal random search strategies arise through the informed combination of only two walk scales (related to the exploitative and the explorative scales, respectively), expanding on the well-known result that optimal strategies in strictly uninformed scenarios are achieved through Lévy paths (or, equivalently, through a hierarchical combination of multiple scales).