The relationship of motor skills and adaptive behavior skills in young children with autism spectrum disorders

ObjectiveTo determine the relationship of motor skills and adaptive behavior skills in young children with autism.DesignA multiple regression analysis tested the relationship of motor skills on the adaptive behavior composite, daily living, adaptive social and adaptive communicative skills holding constant age, non-verbal problem solving, and calibrated autism severity.SettingMajority of the data collected took place in an autism clinic.ParticipantsA cohort of 233 young children with ASD (n = 172), PDD-NOS (n = 22) and non-ASD (developmental delay, n = 39) between the ages of 14–49 months were recruited from early intervention studies and clinical referrals. Children with non-ASD (developmental delay) were included in this study to provide a range of scores indicted through calibrated autism severity.InterventionsNot applicable.Main outcome measuresThe primary outcome measures in this study were adaptive behavior skills.ResultsFine motor skills significantly predicted all adaptive behavior skills (p < 0.01). Gross motor skills were predictive of daily living skills (p < 0.05). Children with weaker motor skills displayed greater deficits in adaptive behavior skills.ConclusionsThe fine and gross motor skills are significantly related to adaptive behavior skills in young children with autism spectrum disorder. There is more to focus on and new avenues to explore in the realm of discovering how to implement early intervention and rehabilitation for young children with autism and motor skills need to be a part of the discussion.     

Length dependent loss of motor axons and altered motor unit properties in human diabetic polyneuropathy

ObjectiveTo assess the number and properties of motor units in an upper and lower limb muscle (tibialis anterior [TA] and first dorsal interosseous [FDI]) in human diabetic polyneuropathy (DPN) using decomposition-based quantitative electromyography (DQEMG).MethodsDQEMG protocols were performed in the TA and FDI of 12 patients with confirmed diabetes mellitus and associated DPN, as well as 12 age-matched control participants. Maximal dorsiflexion strength was also assessed using a dynamometer.ResultsIn both muscles, patients with DPN had significantly reduced motor unit number estimates (MUNEs) (ΔTA ∼45%; ΔFDI ∼30%), compound muscle action potentials (CMAPs) (ΔTA ∼30%; ΔFDI ∼20%), and mean firing rates were reduced (ΔTA ∼15%; ΔFDI ∼15%) compared to controls (p < 0.05). For the TA, patients with DPN had larger mean surface motor unit potentials (SMUPs) (ΔTA ∼40%; p < 0.05), whereas in the FDI no differences were found (p > 0.05).ConclusionsDPN may result in motor unit loss, remodeling, and altered firing rate patterns. The magnitude of changes in the neuromuscular properties of DPN patients are muscle dependent and reflect a length-dependent disease progression.SignificanceDQEMG may be a clinically useful technique in identifying the presence and severity of neuromuscular pathophysiology and tracking disease progression in DPN.     

Effects of overweight and obese body mass on motor planning and motor skills during obstacle crossing in children

Little is known about how obesity relates to motor planning and skills during functional tasks. We collected 3-D kinematics and kinetics as normal weight (n = 10) and overweight/obese (n = 12) children walked on flat ground and as they crossed low, medium, and high obstacles. We investigated if motor planning and motor skill impairments were evident during obstacle crossing. Baseline conditions showed no group differences (all ps > .05). Increased toe clearance was found on low obstacles (p = .01) for the overweight/obese group and on high obstacles (p = .01) for the normal weight group. With the crossing leg, the overweight/obese group had larger hip abduction angles (p = .01) and medial ground reaction forces (p = .006) on high obstacles and high anterior ground reaction forces on low obstacles (p = .001). With the trailing leg, overweight/obese children had higher vertical ground reaction forces on high obstacles (p = .005) and higher knee angles (p = .01) and anterior acceleration in the center of mass (p = .01) on low obstacles. These findings suggest that differences in motor planning and skills in overweight/obese children may be more apparent during functional activities.     

Evaluation of developmental profiles of children with hydrocephalus

ObjectiveThe objective of this study was to compare the developmental characteristics of children with hydrocephalus with those of healthy children.Material and methodsA total of 109 children aged between 2 and 46 months were included in the study, 54 patients diagnosed with hydrocephalus and 55 healthy children were evaluated with demographic data forms and Denver Developmental Screening Test II.ResultsThe mean personal–social (p < 0.001), fine motor-adaptive (p < 0.001), language (p < 0.001), and gross motor subscale scores were significantly lower in children with hydrocephalus than in the control group. Personal–social (p = 0.002) and gross motor (p = 0.029) subscale scores were significantly lower in children with obstructive hydrocephalus than communicating hydrocephalus. There was a significant negative correlation between language scores and ages of the children with hydrocephalus (r = ?0.350, p = 0.009). It was found that children with obstructive hydrocephalus carry a 6.7 folds higher risk of experiencing problems in terms of personal–social development compared to those with communicating hydrocephalus (p = 0.011).ConclusionWe found that patients with hydrocephalus were developmentally retarded compared to the healthy control subjects. Retardation was the most prominent in the obstructive group. Our results showed that neurodevelopmental follow-up should be carried-out regularly in pediatric patients with hydrocephalus, and early intervention should be started in necessary cases.     

Impact of tactile function on upper limb motor function in children with Developmental Coordination Disorder

This study investigated the presence of, and relationship between tactile dysfunction and upper limb motor function in children with Developmental Coordination Disorder (DCD) compared to typical developing (TD) children. Participants were 36 children aged 6–12 years. Presence of DCD (n = 20) or TD (n = 16) was confirmed using the Movement Assessment Battery for Children, second edition. All children participated in a comprehensive assessment of tactile registration (Semmes Weinstein Monofilaments); tactile spatial perception (Single Point Localisation (SPL) and two-point discrimination (2PD)); haptic perception (Stereognosis); speed of simple everyday manual tasks (Jebsen–Taylor Test of Hand Function (JTTHF)); and handwriting speed and accuracy (Evaluation Tool of Children's Handwriting (ETCH)). Compared to TD children, children with DCD demonstrated poorer localisation of touch in the non-dominant hand (p = 0.04), slower speed of alphabet writing (p < 0.05) and less legible handwriting (p < 0.01), but no difference in speed of simple everyday manual tasks (JTTHF: p > 0.05). Regression analysis showed that spatial tactile perception (SPL) predicted handwriting legibility (ETCH: r = 0.11) and speed of functional tasks (JTTHF: r = 0.33). These results suggest that tactile function, specifically single point localisation, should be a primary tactile assessment employed to determine reasons for upper limb motor difficulties experienced by children with DCD.     

Prenatal exposure to the organophosphate pesticide chlorpyrifos and childhood tremor

BackgroundThe organophosphate insecticide chlorpyrifos (CPF), widely used for agricultural purposes, has been linked to neurodevelopmental deficits. Possible motor effects at low to moderate levels of exposure have not been evaluated.MethodsPrenatal exposure to CPF was measured in umbilical cord blood in a sample of 263 inner-city minority children, who were followed prospectively. At approximately 11 years of age (mean age 10.9 ± 0.85 years, range = 9.0–13.9), during a neuropsychological assessment, children were asked to draw Archimedes spirals. These were rated by a senior neurologist specializing in movement disorders who was blind to CPF exposure level.ResultsCompared to all other children, those with prenatal CPF exposure in the upper quartile range (n = 43) were more likely to exhibit mild or mild to moderate tremor (≥1) in either arm (p = 0.03), both arms (p = 0.02), the dominant arm (p = 0.01), and the non-dominant arm (p = 0.055). Logistic regression analyses showed significant CPF effects on tremor in both arms, either arm, the dominant arm (p-values <0.05), and the non-dominant arm (p = 0.06), after adjustment for sex, age at testing, ethnicity, and medication.ConclusionPrenatal CPF exposure is associated with tremor in middle childhood, which may be a sign of the insecticide's effects on nervous system function.     

Intra-rater reliability of motor unit number estimation and quantitative motor unit analysis in subjects with amyotrophic lateral sclerosis

ObjectivesTo assess the intra-rater reliability of decomposition-enhanced spike-triggered averaging (DE-STA) motor unit number estimation (MUNE) and quantitative motor unit potential analysis in the upper trapezius (UT) and biceps brachii (BB) of subjects with amyotrophic lateral sclerosis (ALS) and to compare the results from the UT to control data.MethodsPatients diagnosed with clinically probable or definite ALS completed the experimental protocol twice with the same evaluator for the UT (n = 10) and BB (n = 9).ResultsIntra-rater reliability for the UT was good for the maximum compound muscle action potential (CMAP) (ICC = 0.88), mean surface-detected motor unit potential (S-MUP) (ICC = 0.87) and MUNE (ICC = 0.88), and for the BB was moderate for maximum CMAP (ICC = 0.61), and excellent for mean S-MUP (ICC = 0.94) and MUNE (ICC = 0.93). A significant difference between tests was found for UT MUNE. Comparing subjects with ALS to control subjects, UT maximum CMAP (p < 0.01) and MUNE (p < 0.001) values were significantly lower, and mean S-MUP values significantly greater (p < 0.05) in subjects with ALS.ConclusionsThis study has demonstrated the ability of the DE-STA MUNE technique to collect highly reliable data from two separate muscle groups and to detect the underlying pathophysiology of the disease.SignificanceThis was the first study to examine the reliability of this technique in subjects with ALS, and demonstrates its potential for future use as an outcome measure in ALS clinical trials and studies of ALS disease severity and natural history.     

Implicit and explicit motor learning: Application to children with Autism Spectrum Disorder (ASD)

Aims and objectivesThis study aims to determine whether children with Autism Spectrum Disorder (ASD) are capable of learning a motor skill both implicitly and explicitly.MethodsIn the present study, 30 boys with ASD, aged 7–11 with IQ average of 81.2, were compared with 32 typical IQ- and age-matched boys on their performance on a serial reaction time task (SRTT). Children were grouped by ASD and typical children and by implicit and explicit learning groups for the SRTT.ResultsImplicit motor learning occurred in both children with ASD (p = .02) and typical children (p = .01). There were no significant differences between groups (p = .39). However, explicit motor learning was only observed in typical children (p = .01) not children with ASD (p = .40). There was a significant difference between groups for explicit learning (p = .01).DiscussionThe results of our study showed that implicit motor learning is not affected in children with ASD. Implications for implicit and explicit learning are applied to the CO-OP approach of motor learning with children with ASD.     

A four year follow-up of sleep and respiratory measures in elementary school-aged children with sleep disordered breathing

ObjectiveLittle is known of the long-term prognosis of children treated for sleep disordered breathing (SDB) and even less of children with milder forms of SDB who remain untreated. We aimed to investigate the long-term sleep and respiratory outcomes of children with a range of SDB severities.Methods41 children with SDB and 20 non snoring controls (mean age, 12.9 ± 0.2 y), underwent repeat overnight polysomnography (PSG) 4.0 ± 0.3 years after initial diagnosis. SDB severity, presence of snoring, sleep and respiratory parameters, sleep fragmentation index (SFI), the Pediatric Daytime Sleepiness Scale (PDSS), Sleep Disturbance Scale for Children (SDSC), and obstructive sleep apnea 18-item quality of life questionnaire were re assessed. Children with SDB were grouped into resolved (no snoring and obstructive apnea–hypopnea index [OAHI] <1) and unresolved (snoring or an OAHI ⩾1).ResultsAt follow-up OAHI was reduced in both SDB groups (p < 0.05); however, 54% (n = 22) of children still continued to snore, having either persistent or new OSA (n = 4). In this unresolved group, sleep was significantly disrupted; % nonrapid eye movement stage 1 (NREM1) sleep and SFI were increased (p < 0.05), and total sleep time (TST) and sleep efficiency were decreased compared to the resolved and control groups (p < 0.05). Overall, 29% of children were treated, and of these, 67% had resolved SDB. SDB groups had higher PDSS, SDSC, and OSA-18 scores compared to controls at follow-up (p < 0.01).ConclusionsOur study demonstrated that although SDB improved in the long-term, more than 50% of children had residual SDB (mostly primary snoring) and sleep disturbance. As even mild forms of SDB are known to have adverse cardiovascular, learning, and behavioral outcomes, which have implications for the health of these children.     

Uric acid excretion in North American and Southeast European children with obstructive sleep apnea

Background and objectivesResponses to nocturnal hypoxemia accompanying sleep-disordered breathing (SDB) may vary in different populations. Aims of this study were to (1) assess whether severity of SDB is related to uric acid excretion in North American and Southeast European children and (2) evaluate the interaction between nocturnal hypoxemia and country of children’s origin in uric acid excretion.MethodsConsecutive US and Greek children with snoring who were referred for polysomnography were recruited. Uric acid excretion expressed as uric acid-to-creatinine concentrations ratio in a morning urine specimen was the primary outcome measure.ResultsOne hundred and twenty-six US children (6.8 ± 0.7 years old) and 123 Greek children (6.4 ± 2.5 years old) were recruited. Forty-three US and 53 Greek participants had moderate-to-severe nocturnal hypoxemia (SpO₂ nadir <90%). Obstructive apnea-hypopnea index and SpO₂ nadir were related to uric acid excretion in Greek (but not US) children after adjustment by age, gender and body mass index z-score (p < 0.05). There was a significant interaction between severity of hypoxemia and country of children’s origin in uric acid excretion after adjustment by age, gender and body mass index z-score (p = 0.036). Greek children with moderate-to-severe hypoxemia had higher uric acid excretion (0.85 ± 0.35) than those with mild/no hypoxemia (0.69 ± 0.25) (p = 0.005). US children with moderate-to-severe hypoxemia (0.41 ± 0.20) did not differ in uric acid excretion from those with mild/no hypoxemia (0.42 ± 0.22) (p = 0.823).ConclusionsUric acid excretion differs in children with SDB and different ethnic backgrounds or environmental exposures.     

Assessment of physical fitness and exercise tolerance in children with developmental coordination disorder

Children with developmental coordination disorder (DCD) have been shown to be less physically fit when compared to their typically developing peers. The purpose of the present study was to examine the relationships among body composition, physical fitness and exercise tolerance in children with and without DCD. Thirty-seven children between the ages of 7 and 9 years participated in this study. Participants were classified according to results obtained on the Movement Assessment Battery for Children (MABC) and were divided in 2 groups: 19 children with DCD and 18 children without DCD. All children performed the following physical fitness tests: The five-jump test (5JT), the triple-hop distance (THD) and the modified agility test (MAT). Walking distance was assessed using the 6-min walking test (6MWT). Children with DCD showed higher scores than children without DCD in all MABC subscale scores, as well as in the total score (p < 0.001). Participants with DCD were found to perform significantly worse on the MAT (p < 0.001), the THD (p < 0.001) and 5JT (p < 0.05). Moreover, children with DCD had poorer performance on the 6MWT than children without DCD (p < 0.01). Our results found significant correlations among body mass index (BMI), THD (r = 0.553, p < 0.05), 5JT (r = 0.480, p < 0.05) and 6MWT (r = 0.544, p < 0.05) only in DCD group. A significant correlation between MAT and 5JT (r = −0.493, p < 0.05) was found. Similarly, THD and 5JT (r = 0.611, p < 0.01) was found to be correlated in children with DCD. We also found relationships among 6MWT and MAT (r = −0.522, p < 0.05) and the 6MWT and 5JT (r = 0.472, p < 0.05) in DCD group. In addition, we found gender specific patterns in the relationship between exercise tolerance, explosive strength, power, DCD, and BMI. In conclusion, the present study revealed that BMI was indicative of poorer explosive strength, power and exercise tolerance in children with DCD compared to children without DCD probably due to a limited coordination on motor control.     

Seat surface inclination may affect postural stability during Boccia ball throwing in children with cerebral palsy

The aim of the study was to examine how seat surface inclination affects Boccia ball throwing movement and postural stability among children with cerebral palsy (CP). Twelve children with bilateral spastic CP (3 with gross motor function classification system Level I, 5 with Level II, and 4 with Level III) participated in this study. All participants underwent pediatric reach tests and ball throwing performance analyses while seated on 15° anterior- or posterior-inclined, and horizontal surfaces. An electromagnetic motion analysis system was synchronized with a force plate to assess throwing motion and postural stability. The results of the pediatric reach test (p = 0.026), the amplitude of elbow movement (p = 0.036), peak vertical ground reaction force (PVGRF) (p < 0.001), and movement range of the center of pressure (COP) (p < 0.020) were significantly affected by seat inclination during throwing. Post hoc comparisons showed that anterior inclination allowed greater amplitude of elbow movement and PVGRF, and less COP movement range compared with the other inclines. Posterior inclination yielded less reaching distance and PVGRF, and greater COP movement range compared with the other inclines. The anterior-inclined seat yielded superior postural stability for throwing Boccia balls among children with bilateral spastic CP, whereas the posterior-inclined seat caused difficulty.     

CMAP scan discontinuities: Automated detection and relation to motor unit loss

ObjectiveTo evaluate an automated method that extracts motor unit (MU) information from the CMAP scan, a high-detail stimulus–response curve recorded with surface EMG. Discontinuities in the CMAP scan are hypothesized to result from MU loss and reinnervation.MethodsWe introduce the parameter D50 to quantify CMAP scan discontinuities. D50 was compared with a previously developed manual score in 253 CMAP scans and with a simultaneously obtained motor unit number estimate (MUNE) in 173 CMAP scans. The effect of MU loss on D50 was determined with a simulation model.ResultsWe found a high agreement (sensitivity = 86.8%, specificity = 96.6%) between D50 and the manual score. D50 and MUNE were significantly correlated below 80 MUs (r = 0.65, n = 68, p < 0.001), but not when MUNE was larger than 120 MUs (r = 0.23, n = 59, p = 0.08).ConclusionsDiscontinuities in the CMAP scan as expressed by a decreased D50 are related to significant MU loss. The determination of D50 is objective, quantitative, and less time-consuming than both manual scoring and many existing MUNE methods.SignificanceD50 is potentially useful to monitor neurogenic disorders and moderate to severe MU loss.     

Polyneuropathy induced by HIV disease and antiretroviral therapy

ObjectiveTo investigate the underlying mechanisms of polyneuropathy induced by HIV infection or antiretroviral drugs.MethodsWe tested 100 HIV patients (59 with AIDS). Ninety-three patients received antiretroviral drugs. Forty-four were treated with neurotoxic compounds (ddI, ddC, d4T). Nerve conduction velocities and the sympathetic skin response (SSR) in palms and soles were measured in all patients. In skin biopsies (ankle and thigh), the intraepidermal nerve fiber density (IENFD) and the number of epidermal fibers without contact to the basal membrane (fragments) were quantified using PGP9.5 staining.ResultsSeverity of the disease (CD4 + count) correlated to conduction velocities of peroneal (p < 0.01, Spearmans rank correlation), sural (p < 0.01) and median nerves (p < 0.05/p < 0.001, sensory/motor). In contrast, the duration of neurotoxic treatment did not impair conduction velocities (p > 0.3) but correlated to reduced IENFD in the ankle (r = ?0.24, p < 0.05). Despite their reduced IENFD, patients with long neurotoxic treatment had a high number of fragments irrespective of their CD4 + count.ConclusionsNeurotoxic treatment appears to primarily impair thin fiber conduction, whereas HIV neuropathy is linked to large fiber impairment and reduction of fragments of nerve fibers.SignificanceThese findings emphasize the differential pattern of polyneuropathy in HIV patients caused by the infection or induced by antiretroviral treatment.     

Daily training with realistic visual feedback improves reproducibility of event-related desynchronisation following hand motor imagery

ObjectiveFew brain–computer interface (BCI) studies have addressed learning mechanisms by exposure to visual feedback that elicits scalp electroencephalogram. We examined the effect of realistic visual feedback of hand movement associated with sensorimotor rhythm.MethodsThirty-two healthy participants performed in five daily training in which they were shown motor imagery of their dominant hand. Participants were randomly assigned to 1 of 4 experimental groups receiving different types of visual feedback on event-related desynchronisation (ERD) derived over the contralateral sensorimotor cortex: no feedback as a control, bar feedback with changing bar length, anatomically incongruent feedback in which the hand open/grasp picture on screen was animated at eye level, and anatomically congruent feedback in which the same hand open/grasp picture was animated on the screen overlaying the participant’s hand.ResultsDaily training with all types of visual feedback induced more robust ERD than the no feedback condition (p < 0.05). The anatomically congruent feedback produced the highest reproducibility of ERD with the smallest inter-trial variance (p < 0.05).ConclusionRealistic feedback training is a suitable method to acquire the skill to control a BCI system.SignificanceThis finding highlights the possibility of improvement of reproducibility of ERD and can help to use BCI techniques.     

Influence of methylphenidate on motor performance and attention in children with developmental coordination disorder and attention deficit hyperactive disorder

Individuals with attention deficit hyperactive disorder (ADHD) often have coexisting developmental coordination disorder (DCD). The positive therapeutic effect of methylphenidate on ADHD symptoms is well documented, but its effects on motor coordination are less studied. We assessed the influence of methylphenidate on motor performance in children with comorbid DCD and ADHD. Participants were 30 children (24 boys) aged 5.10–12.7 years diagnosed with both DCD and ADHD. Conners’ Parent Rating Scale was used to reaffirm ADHD diagnosis and the Developmental Coordination Disorder Questionnaire was used to diagnose DCD. The Movement Assessment Battery for Children-2 and the online continuous performance test were administrated to all participants twice, with and without methylphenidate. The tests were administered on two separate days in a blind design. Motor performance and attention scores were significantly better with methylphenidate than without it (p < 0.001 for improvement in the Movement Assessment Battery for Children-2 and p < 0.006 for the online continuous performance test scores).The findings suggest that methylphenidate improves both attention and motor coordination in children with coexisting DCD and ADHD. More research is needed to disentangle the causality of the improvement effect and whether improvement in motor coordination is directly affected by methylphenidate or mediated by improvement in attention.     

Does early communication mediate the relationship between motor ability and social function in children with cerebral palsy?

BackgroundChildren diagnosed with neurodevelopmental conditions such as cerebral palsy (CP) are at risk of experiencing restrictions in social activities negatively impacting their subsequent social functioning. Research has identified motor and communication ability as being unique determinants of social function capabilities in children with CP, to date, no research has investigated whether communication is a mediator of the relationship between motor ability and social functioning.AimsTo investigate whether early communication ability at 24 months corrected age (ca.) mediates the relationship between early motor ability at 24 months ca. and later social development at 60 months ca. in a cohort of children diagnosed with cerebral palsy (CP).MethodA cohort of 71 children (43 male) diagnosed with CP (GMFCS I = 24, 33.8%, II = 9, 12.7%, III = 12, 16.9%, IV = 10, 14.1%, V = 16, 22.5%) were assessed at 24 and 60 months ca. Assessments included the Gross Motor Function Measure (GMFM), the Communication and Symbolic Behaviour Scales-Developmental Profile (CSBS-DP) Infant-Toddler Checklist and the Paediatric Evaluation of Disability Inventory (PEDI). A mediation model was examined using bootstrapping.ResultsEarly communication skills mediated the relationship between early motor abilities and later social functioning, b = 0.24 (95% CI = 0.08–0.43 and the mediation model was significant, F (2, 68) = 32.77, p < 0.001, R² = 0.49.Conclusions and implicationEarly communication ability partially mediates the relationship between early motor ability and later social function in children with CP. This demonstrates the important role of early communication in ongoing social development. Early identification of communication delay and enriched language exposure is crucial in this population.     

Impaired blood pressure control in children with obstructive sleep apnea

BackgroundObstructive sleep apnea (OSA) in adults has been associated with hypertension, low baroreflex sensitivity (BRS), a delayed heart rate response to changing blood pressure (heart period delay [HPD]), and increased blood pressure variability (BPV). Poor BRS may contribute to hypertension by impairing the control of blood pressure (BP), with increased BPV and HPD. Although children with OSA have elevated BP, there are scant data on BRS, BPV, or HPD in this group.Methods105 children ages 7–12 years referred for assessment of OSA and 36 nonsnoring controls were studied. Overnight polysomnography (PSG) was performed with continuous BP monitoring. Subjects were assigned to groups according to their obstructive apnea–hypopnea index (OAHI): primary snoring (PS) (OAHI ⩽1 event/h), mild OSA (OAHI > 1–⩽5 events/h) and moderate/severe (MS) OSA (OAHI > 5 events/h). BRS and HPD were calculated using cross spectral analysis and BPV using power spectral analysis.ResultsSubjects with OSA had significantly lower BRS (p < .05 for both) and a longer HPD (PS and MS OSA, p < .01; mild OSA, p < .05) response to spontaneous BP changes compared with controls. In all frequencies of BPV, the MS group had higher power compared with the control and PS groups (low frequency [LF], p < .05; high frequency [HF], p < .001).ConclusionsOur study demonstrates reduced BRS, longer HPD, and increased BPV in subjects with OSA compared to controls. This finding suggests that children with OSA have altered baroreflex function. Longitudinal studies are required to ascertain if this dampening of the normal baroreflex response can be reversed with treatment.     

Blink reflex in patients with postparalytic facial syndrome and blepharospasm: Trigeminal and auditory stimulation

ObjectiveThe enhancement of blink reflex (BR) excitability was shown in patients with postparalytic facial syndrome (PFS) and essential blepharospasm (EB). We prospectively investigated patients with PFS and EB whether BR alterations demonstrated by trigeminal stimulation will similarly be observed upon auditory stimulation.MethodsFifteen patients with PFS, 15 patients with EB, and 30 healthy volunteers were involved. Electrically stimulated trigeminal BR and auditory BR were studied bilaterally.ResultsThe mean R2 amplitude and duration values were highest in EB patients, being significantly higher than PFS patients (p < 0.05) and control group (p < 0.01). The mean R2 duration in PFS patients were also significantly longer in compared to control group (p = 0.025). EB patients showed a higher mean R (auditory) amplitude and duration than PFS patients (p < 0.05) and controls (p < 0.04). The mean R (auditory) duration was longer on symptomatic side of PFS patients in compared to controls (p = 0.05).ConclusionsWe observed that there is an enhanced excitability of BR circuit in postparalytic facial syndrome and essential blepharospasm, which could be evoked by auditory stimulation in addition to trigeminal stimulation.SignificanceThe enhanced excitability in patients with EB and PFS probably originates from the final common pathway of BR circuit, namely facial motor or premotor neurons.     

Functional repetitive transcranial magnetic stimulation increases motor cortex excitability in survivors of stroke

ObjectiveTo determine if repetitive transcranial magnetic stimulation (rTMS) applied to the motor cortex with simultaneous voluntary muscle activation, termed functional-rTMS, will promote greater neuronal excitability changes and neural plasticity than passive-rTMS in survivors of stroke.MethodsEighteen stroke survivors were randomized into functional-rTMS (EMG-triggered rTMS) or passive-rTMS (rTMS only; control) conditions. Measures of short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF), force steadiness (coefficient of variation, CV) at 10% of maximum voluntary contraction, and pinch task muscle activity were assessed before and after rTMS. Functional-rTMS required subjects to exceed a muscle activation threshold to trigger each rTMS train; the passive-rTMS group received rTMS while relaxed.ResultsSignificant interactions (time × condition) were observed in abductor pollicis brevis (APB) SICI, APB ICF, CV of force, and APB muscle activity. Functional-rTMS decreased APB SICI (p < 0.05) and increased ICF (p < 0.05) after stimulation, whereas passive-rTMS decreased APB muscle activity (p < 0.01) and decreased CV of force (p < 0.05). No changes were observed in FDI measures (EMG, ICF, SICI).Conclusion(s)Functional-rTMS increased motor cortex excitability, i.e., less SICI and more ICF for the APB muscle. Passive stimulation significantly reduced APB muscle activity and improved steadiness.SignificanceFunctional-rTMS promoted greater excitability changes and selectively modulated agonist muscle activity.