Muscle Reflex Research Articles

Improving the therapeutic efficacy of prilocaine by PLGA microparticles: Preparation, characterization and in vivo evaluation

A delivery system based on poly(lactic-co-glycolic acid) polymer (PLGA) microparticles has been developed for parenteral administration of the local anesthetic prilocaine in its free base form. Both drug-free and drug-loaded microparticles, prepared by a double-emulsion-evaporation method, were characterized for mean size by Laser Diffraction Analysis, while their morphology was investigated by scanning electron microscopy. The preparation technique allowed obtainment of homogeneous microparticles of about 25 µm diameter, suitable for subcutaneous administration. The encapsulation efficiency, determined by both direct and indirect methods, was around 36–38%. Differential Scanning Calorimetry was used to characterize the solid state of the raw materials, assess drug-polymer compatibility and miscibility and highlight possible modifications of the components induced by the preparation method. In vitro release studies showed a sustained release profile, with about 80% of drug released after the first 24 h. The anesthetic effect of the formulation was evaluated in vivo on rats, according to the test of cutaneous trunci muscle reflex. Administration of prilocaine base as PLGA microparticles allowed to significantly enhance both extent (60% AUC increase) and duration (100% increase) of the anesthetic effect in the animal model, in comparison with the equivalent dose of prilocaine hydrochloride aqueous solution.

Click-Evoked Auditory Efferent Activity: Rate and Level Effects.

There currently are no standardized protocols to evaluate auditory efferent function in humans. Typical tests use broadband noise to activate the efferents, but only test the contralateral efferent pathway, risk activating the middle ear muscle reflex (MEMR), and are laborious for clinical use. In an attempt to develop a clinical test of bilateral auditory efferent function, we have designed a method that uses clicks to evoke efferent activity, obtain click-evoked otoacoustic emissions (CEOAEs), and monitor MEMR. This allows for near-simultaneous estimation of cochlear and efferent function. In the present study, we manipulated click level (60, 70, and 80dB peak-equivalent sound pressure level [peSPL]) and rate (40, 50, and 62.5Hz) to identify an optimal rate-level combination that evokes measurable efferent modulation of CEOAEs. Our findings (n = 58) demonstrate that almost all click levels and rates used caused significant inhibition of CEOAEs, with a significant interaction between level and rate effects. Predictably, bilateral activation produced greater inhibition compared to stimulating the efferents only in the ipsilateral or contralateral ear. In examining the click rate-level effects during bilateral activation in greater detail, we observed a 1-dB inhibition of CEOAE level for each 10-dB increase in click level, with rate held constant at 62.5Hz. Similarly, a 10-Hz increase in rate produced a 0.74-dB reduction in CEOAE level, with click level held constant at 80dB peSPL. The effect size (Cohen's d) was small for either monaural condition and medium for bilateral, faster-rate, and higher-level conditions. We were also able to reliably extract CEOAEs from efferent eliciting clicks. We conclude that clicks can indeed be profitably employed to simultaneously evaluate cochlear health using CEOAEs as well as their efferent modulation. Furthermore, using bilateral clicks allows the evaluation of both the crossed and uncrossed elements of the auditory efferent nervous system, while yielding larger, more discernible, inhibition of the CEOAEs relative to either ipsilateral or contralateral condition.

Olivocochlear Efferent Activity Is Associated With the Slope of the Psychometric Function of Speech Recognition in Noise.

The medial olivocochlear (MOC) efferent system can modify cochlear function to improve sound detection in noise, but its role in speech perception in noise is unclear. The purpose of this study was to determine the association between MOC efferent activity and performance on two speech-in-noise tasks at two signal-to-noise ratios (SNRs). It was hypothesized that efferent activity would be more strongly correlated with performance at the more challenging SNR, relative to performance at the less challenging SNR. Sixteen adults aged 35 to 73 years participated. Subjects had pure-tone averages ≤25 dB HL and normal middle ear function. High-frequency pure-tone averages were computed across 3000 to 8000 Hz and ranged from 6.3 to 48.8 dB HL. Efferent activity was assessed using contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs) measured in right ears, and MOC activation was achieved by presenting broadband noise to left ears. Contralateral suppression was expressed as the decibel change in TEOAE magnitude obtained with versus without the presence of the broadband noise. TEOAE responses were also examined for middle ear muscle reflex activation and synchronous spontaneous otoacoustic emissions (SSOAEs). Speech-in-noise perception was assessed using the closed-set coordinate response measure word recognition task and the open-set Institute of Electrical and Electronics Engineers sentence task. Speech and noise were presented to right ears at two SNRs. Performance on each task was scored as percent correct. Associations between contralateral suppression and speech-in-noise performance were quantified using partial rank correlational analyses, controlling for the variables age and high-frequency pure-tone average. One subject was excluded due to probable middle ear muscle reflex activation. Subjects showed a wide range of contralateral suppression values, consistent with previous reports. Three subjects with SSOAEs had similar contralateral suppression results as subjects without SSOAEs. The magnitude of contralateral suppression was not significantly correlated with speech-in-noise performance on either task at a single SNR (p > 0.05), contrary to hypothesis. However, contralateral suppression was significantly correlated with the slope of the psychometric function, computed as the difference between performance levels at the two SNRs divided by 3 (decibel difference between the 2 SNRs) for the coordinate response measure task (partial rs = 0.59; p = 0.04) and for the Institute of Electrical and Electronics Engineers task (partial rs = 0.60; p = 0.03). In a group of primarily older adults with normal hearing or mild hearing loss, olivocochlear efferent activity assessed using contralateral suppression of TEOAEs was not associated with speech-in-noise performance at a single SNR. However, auditory efferent activity appears to be associated with the slope of the psychometric function for both a word and sentence recognition task in noise. Results suggest that individuals with stronger MOC efferent activity tend to be more responsive to changes in SNR, where small increases in SNR result in better speech-in-noise performance relative to individuals with weaker MOC efferent activity. Additionally, the results suggest that the slope of the psychometric function may be a more useful metric than performance at a single SNR when examining the relationship between speech recognition in noise and MOC efferent activity.

The Middle Ear Muscle Reflex in Rat: Developing a Biomarker of Auditory Nerve Degeneration.

The long-term goal of this research is to determine whether the middle ear muscle reflex can be used to predict the number of healthy auditory nerve fibers in hearing-impaired ears. In this study, we develop a high-impedance source and an animal model of the middle ear muscle reflex and explore the influence of signal frequency and level on parameters of the reflex to determine an optimal signal to examine auditory nerve fiber survival. A high-impedance source was developed using a hearing aid receiver attached to a 0.06 diameter 10.5-cm length tube. The impedance probe consisted of a microphone probe placed near the tip of a tube coupled to a sound source. The probe was calibrated by inserting it into a syringe of known volumes and impedances. The reflex in the anesthetized rat was measured with elicitor stimuli ranging from 3 to 16 kHz presented at levels ranging from 35 to 100 dB SPL to one ear while the reflex was measured in the opposite ear containing the probe and probe stimulus. The amplitude of the reflex increased with elicitor level and was largest at 3 kHz. The lowest threshold was approximately 54 dB SPL for the 3-kHz stimulus. The rate of decay of the reflex was greatest at 16 kHz followed by 10 and 3 kHz. The rate of decay did not change significantly with elicitor signal level for 3 and 16 kHz, but decreased as the level of the 10-kHz elicitor increased. A negative feedback model accounts for the reflex decay by having the strength of feedback dependent on auditory nerve input. The rise time of the reflex varied with frequency and changed with level for the 10- and 16-kHz signals but not significantly for the 3-kHz signal. The latency of the reflex increased with a decrease in elicitor level, and the change in latency with level was largest for the 10-kHz stimulus. Because the amplitude of the reflex in rat was largest with an elicitor signal at 3 kHz, had the lowest threshold, and yielded the least amount of decay, this may be the ideal frequency to estimate auditory nerve survival in hearing-impaired ears.

History-dependence of muscle slack length following contraction and stretch in the human vastus lateralis.

In reduced muscle preparations, the slack length and passive stiffness of muscle fibres have been shown to be influenced by previous muscle contraction or stretch. In human muscles, such behaviours have been inferred from measures of muscle force, joint stiffness and reflex magnitudes and latencies. Using ultrasound imaging, we directly observed that isometric contraction of the vastus lateralis muscle at short lengths reduces the slack lengths of the muscle-tendon unit and muscle fascicles. The effect is apparent 60s after the contraction. These observations imply that muscle contraction at short lengths causes the formation of bonds which reduce the effective length of structures that generate passive tension in muscles. In reduced muscle preparations, stretch and muscle contraction change the properties of relaxed muscle fibres. In humans, effects of stretch and contraction on properties of relaxed muscles have been inferred from measurements of time taken to develop force, joint stiffness and reflex latencies. The current study used ultrasound imaging to directly observe the effects of stretch and contraction on muscle-tendon slack length and fascicle slack length of the human vastus lateralis muscle in vivo. The muscle was conditioned by (a) strong isometric contractions at long muscle-tendon lengths, (b) strong isometric contractions at short muscle-tendon lengths, (c) weak isometric contractions at long muscle-tendon lengths and (d) slow stretches. One minute after conditioning, ultrasound images were acquired from the relaxed muscle as it was slowly lengthened through its physiological range. The ultrasound image sequences were used to identify muscle-tendon slack angles and fascicle slack lengths. Contraction at short muscle-tendon lengths caused a mean 13.5degree (95% CI 11.8-15.0degree) shift in the muscle-tendon slack angle towards shorter muscle-tendon lengths, and a mean 5mm (95% CI 2-8mm) reduction in fascicle slack length, compared to the other conditions. A supplementary experiment showed the effect could be demonstrated if the muscle was conditioned by contraction at short lengths but not if the relaxed muscle was held at short lengths, confirming the role of muscle contraction. These observations imply that muscle contraction at short lengths causes the formation of bonds which reduce the effective length of structures that generate passive tension in muscles.

Automatic gain control of neural coupling during cooperative hand movements

Cooperative hand movements (e.g. opening a bottle) are controlled by a task-specific neural coupling, reflected in EMG reflex responses contralateral to the stimulation site. In this study the contralateral reflex responses in forearm extensor muscles to ipsilateral ulnar nerve stimulation was analyzed at various resistance and velocities of cooperative hand movements. The size of contralateral reflex responses was closely related to the level of forearm muscle activation required to accomplish the various cooperative hand movement tasks. This indicates an automatic gain control of neural coupling that allows a rapid matching of corrective forces exerted at both sides of an object with the goal ‘two hands one action’.

The effect of interaural timing on the posterior auricular muscle reflex in normal adult volunteers

The posterior auricular muscle (PAM) reflex to sounds has been used clinically to determine hearing threshold as an alternative to other audiological diagnostic measures such as the auditory brainstem response. We have shown that the PAM response is also sensitive to interaural timing differences in normally hearing adults. PAM responses were evoked by both ipsilateral/ contralateral monaural stimulation and by binaural stimulation. Introducing sound delays ipsilaterally or contralaterally decreased the PAM response amplitude and increased its latency. The PAM response in this study shows a qualitatively similar pattern to that seen by the binaural interaction component (BIC) of the auditory brainstem potential to binaural clicks described in previous studies, in that both: have their shortest latency and maximal amplitudes centred around zero interaural timing differences, have response latencies increase with increasing interaural delays up to 1.2 ms and have response amplitudes decrease with increasing interaural delays of up to 1.2 ms. Our data show that the PAM response may be useful in measuring binaural integration in humans non-invasively for diagnostic or research studies.

Augmented exercise pressor response during static handgrip in women with PTSD

Post‐traumatic stress disorder (PTSD) is a psychiatric illness that is more prevalent in women than men, and there is growing evidence suggesting a clear link between PTSD and future development of cardiovascular disease. The underlying mechanisms are unclear, but enhanced sympatheticreactivity to daily stressors may be involved. We hypothesized that PTSD women would have an augmented vasomotor sympathetic response to static exercise. We measured heart rate (HR), blood pressure (BP), and muscle sympathetic nerve activity (MSNA) in 12 female patients with PTSD and 8 healthy women (controls) during static handgrip (SHG) exercise to fatigue at 40% of maximal voluntary contraction (MVC) force followed by 2 min of postexercise circulatory arrest (PECA) and 3 min of recovery. The total SHG time was divided evenly into five stages. Age, body mass index, and body surface area were not different between groups. MVC and the time to fatigue during SHG did not differ between patients and controls (P>0.05). MSNA burst frequency (BF) in response to SHG was greater in patients than controls (timexgroup interaction P=0.03, time P=0.0001, group P=0.04), but not during PECA. During the early stages of SHG, PTSD patients showed greater MSNA BF compared to controls [stage 1: 40±5 (SE) vs.19±7 bursts/min; P=0.02, stage 2: 45±6 vs.25±7; P=0.03, stage 3: 55±6 vs.30±7; P=0.02). MSNA BF responses during stage 4 and 5 were not different between groups (P=0.09 and P=0.1, respectively). Similarly, PTSD patients showed greater systolic blood pressure (SBP) compared to controls during early stages of SHG (stage 1: 144±4 vs.129±5 mmHg; P=0.02, stage 2: 149±4 vs.132±5; P=0.03, stage 3: 159±6 vs.138±7; P=0.03, stage 4: 166±6 vs.143±7; P=0.04) but not in the last stage (at fatigue; P=0.2). SBP was not different between groups during PECA and recovery. Diastolic BP and HR were progressively increased during SHG, reached peak at the last stage, and were comparable between groups. These results suggest that women with PTSD have an augmented exercise pressor response, which may be attributed to enhanced mechano‐ rather than metabo‐reflexes. However, the actual role of the muscle reflex in cardiovascular risk in PTSD remains to be elucidated.Support or Funding InformationThis study is supported by Harry S. Moss Heart Trust research funding STU 082016‐057This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Intralimb and Interlimb Cutaneous Reflexes during Locomotion in the Intact Cat.

When the foot contacts an obstacle during locomotion, cutaneous inputs activate spinal circuits to ensure dynamic balance and forward progression. In quadrupeds, this requires coordinated reflex responses between the four limbs. Here, we investigated the patterns and phasic modulation of cutaneous reflexes in forelimb and hindlimb muscles evoked by inputs from all four limbs. Five female cats were implanted to record muscle activity and to stimulate the superficial peroneal and superficial radial nerves during locomotion. Stimulating these nerves evoked short-, mid-, and longer-latency excitatory and/or inhibitory responses in all four limbs that were phase-dependent. The largest responses were generally observed during the peak activity of the muscle. Cutaneous reflexes during mid-swing were consistent with flexion of the homonymous limb and accompanied by modification of the stance phases of the other three limbs, by coactivating flexors and extensors and/or by delaying push-off. Cutaneous reflexes during mid-stance were consistent with stabilizing the homonymous limb by delaying and then facilitating its push-off and modifying the support phases of the homolateral and diagonal limbs, characterized by coactivating flexors and extensors, reinforcing extensor activity and/or delaying push-off. The shortest latencies of homolateral and diagonal responses were consistent with fast-conducting disynaptic or trisynaptic pathways. Descending homolateral and diagonal pathways from the forelimbs to the hindlimbs had a higher probability of eliciting responses compared with ascending pathways from the hindlimbs to the forelimbs. Thus, in quadrupeds, intralimb and interlimb reflexes activated by cutaneous inputs ensure dynamic coordination of the four limbs, producing a whole-body response.SIGNIFICANCE STATEMENT The skin contains receptors that, when activated, send inputs to spinal circuits, signaling a perturbation. Rapid responses, or reflexes, in muscles of the contacted limb and opposite homologous limb help maintain balance and forward progression. Here, we investigated reflexes during quadrupedal locomotion in the cat by electrically stimulating cutaneous nerves in each of the four limbs. Functionally, responses appear to modify the trajectory or stabilize the movement of the stimulated limb while modifying the support phase of the other limbs. Reflexes between limbs are mediated by fast-conducting pathways that involve excitatory and inhibitory circuits controlling each limb. The comparatively stronger descending pathways from cervical to lumbar circuits controlling the forelimbs and hindlimbs, respectively, could serve a protective function.

Effects of cochlear synaptopathy on middle-ear muscle reflexes in unanesthetized mice

Cochlear synaptopathy, i.e. the loss of auditory-nerve connections with cochlear hair cells, is seen in aging, noise damage, and other types of acquired sensorineural hearing loss. Because the subset of auditory-nerve fibers with high thresholds and low spontaneous rates (SRs) is disproportionately affected, audiometric thresholds are relatively insensitive to this primary neural degeneration. Although suprathreshold amplitudes of wave I of the auditory brainstem response (ABR) are attenuated in synaptopathic mice, there is not yet a robust diagnostic in humans. The middle-ear muscle reflex (MEMR) might be a sensitive metric (Valero et al., 2016), because low-SR fibers may be important drivers of the MEMR (Liberman and Kiang, 1984; Kobler et al., 1992). Here, to test the hypothesis that narrowband reflex elicitors can identify synaptopathic cochlear regions, we measured reflex growth functions in unanesthetized mice with varying degrees of noise-induced synaptopathy and in unexposed controls. To separate effects of the MEMR from those of the medial olivocochlear reflex, the other sound-evoked cochlear feedback loop, we used a mutant mouse strain with deletion of the acetylcholine receptor required for olivocochlear function. We demonstrate that the MEMR is normal when activated from non-synaptopathic cochlear regions, is greatly weakened in synaptopathic regions, and is a more sensitive indicator of moderate synaptopathy than the suprathreshold amplitude of ABR wave I.

Reactive balance performance and neuromuscular and cognitive responses to unpredictable balance perturbations in children with developmental coordination disorder

Developmental coordination disorder (DCD) is a common motor disorder affecting balance performance. However, few studies have investigated reactive balance performance and the underlying mechanisms in children with DCD. This study aimed to compare the reactive balance performance, lower limb muscle reflex contraction latency and attention level in response to unpredictable balance perturbations between 100 typically developing children and 120 children with DCD (with and without comorbid autism spectrum disorder) aged 6–9 years. Reactive balance performance was evaluated using a motor control test (MCT) conducted on a computerized dynamic posturography machine. The lower limb postural muscle responses and attention level before, during and after a MCT were measured using surface electromyography and electroencephalography, respectively. The results revealed that relative to typically developing children, those with DCD had a significantly longer MCT latency score in the backward platform translation condition (p = 0.048) but a significantly shorter latency score in the forward platform translation condition (p = 0.024). The MCT composite latency scores and the corresponding lower limb muscle onset latencies were similar between the groups. Children with DCD also demonstrated a lower attention level during and after sudden backward (p = 0.042) and forward (p = 0.031) platform translations, compared to typically developing children. Children with DCD were less attentive in response to postural threats, and their balance responses were direction-specific. Balance training for children with DCD might require an additional emphasis on sudden posterior-to-anterior balance perturbations, as well as on problems with inattention.

Delayed Latency of Postural Muscles of Individuals with Intellectual Disabilities.

Individuals with intellectual disabilities (ID) (50 < IQ < 79) show impaired motor and postural control, these impairments are highly related to falls and injuries. Recent studies demonstrated these impairments are related with fine and gross motor development, which are more strongly associated with cognition, and consequently language for individuals with ID than for without ID. Despite these studies, little is known about the structure and functioning of this population's spinal cord, which is highly involved in postural control. The aim of our study was to assess the latency of the reflex responses in postural muscles after unexpected lateral external perturbations, in individuals with intellectual disabilities compared to typically developed participants. We assessed 16 participants with intellectual disabilities, 9 males and 7 females (aged 24.06 ± 8.66 years) and 20 typical developed participants (CG), 11 females, 9 males, (aged 21.20±1.96 years). While the participants were in an upright standing position electromyography was used to collect data from M. obliquus externus abdominis (OE) muscles, which were activated by unpredictable perturbations applied by a servomotor on a hand-held grip, following the lateral external perturbation to the trunk. The intellectual disabilities group presented contralateral OE muscles latency of 85.71±27.24 ms, and CG group presented 68.62±10.25 ms, no differences was found. Ipsilateral OE muscles latency also did not differs between the groups, ID group showed 96.60±30.20 ms and CG group showed 95.57±33.53 ms. Our study furthers the knowledge about the muscular activity of individuals with intellectual disabilities. The present experimental results may suggest unique spinal cord processing of individuals with intellectual disabilities when they are faced with unexpected lateral external perturbations.

Female genito-pelvic reflexes: an overview

ABSTRACTThe female reproductive system includes an active and responsive genital tract that shows involuntary activity triggered by sexual arousal, genital stimulation and/or orgasm. This pelvic and perineal somatic and autonomic reflex muscle activity (“genito-pelvic reflexes”) may be an important constituent of the female sexual response. The aim of this study was to review the literature critically on female genito-pelvic reflexes. Only a small number of studies (15) have been published on this issue. More neurophysiological research is needed to search for the implications of these genito-pelvic reflexes for female sexual (dys)function.

Hearing impairment in patients with myotonic dystrophy type 2

To systematically assess auditory characteristics of a large cohort of patients with genetically confirmed myotonic dystrophy type 2 (DM2). Patients with DM2 were included prospectively in an international cross-sectional study. A structured interview about hearing symptoms was held. Thereafter, standardized otologic examination, pure tone audiometry (PTA; 0.25, 0.5, 1, 2, 4, and 8 kHz), speech audiometry, tympanometry, acoustic middle ear muscle reflexes, and brainstem auditory evoked potentials (BAEP) were performed. The ISO 7029 standard was used to compare the PTA results with established hearing thresholds of the general population according to sex and age. Thirty-one Dutch and 25 French patients with DM2 (61% female) were included with a mean age of 57 years (range 31-78). The median hearing threshold of the DM2 cohort was higher for all measured frequencies, compared to the 50th percentile of normal (p < 0.001). Hearing impairment was mild in 39%, moderate in 21%, and severe in 2% of patients with DM2. The absence of an air-bone gap with PTA, concordant results of speech audiometry with PTA, and normal findings of BAEP suggest that the sensorineural hearing impairment is located in the cochlea. A significant correlation was found between hearing impairment and age, even when corrected for presbycusis. Cochlear sensorineural hearing impairment is a frequent symptom in patients with DM2, suggesting an early presbycusis. Therefore, we recommend informing about hearing impairment and readily performing audiometry when hearing impairment is suspected in order to propose early hearing rehabilitation with hearing aids when indicated.

Neuromuscular properties of genioglossus activity in healthy adults and obstructive sleep apnea patients

Upper airway patency closely contact with neuromuscular airway regulation during respiratory, especially the activity of the pharyngeal dilators. The genioglossus is the largest pharyngeal dilators with its contraction playing the most important role in keeping the pharyngeal airway open. In healthy individuals, genioglossus activation shows a negative correlation with pharyngeal collapsibility and upper airway resistance. Negative pressure during inspiration can stimulate airway mechanoreceptors to produce a muscle reflex activity. However, in obstructive sleep apnea (OSA) patients, the muscles cannot always compensate for the increased mechanical load, resulting in frequent obstructive breathing events. A number of studies have shown that the collapsibility of upper airway during sleep in OSA patients is closely related to the activity of genioglossus electromyography(GGEMG). The present article describes the current understanding regarding the characters of GGEMG during sleep in healthy adults, as well as the pathophysiology of GGEMG in OSA patients.

Periodontal health status in hospitalized cerebral palsy patients of rural Punjab

Introduction: Cerebral palsy (CP) is an important neurological condition that originates in early childhood but affects individuals throughout the life. It leads to specific motor skill problems, delay in developmental milestones, and physical limitations such as abnormal muscle tonus, reflexes, and persistent infantile reflexes. Periodontal disease is the most prevalent oral condition in hospitalized CP patients. These patients are at a higher risk of periodontal disease due to physical and cognitive impairment. The lack of awareness and availability of oro dental care facilities in rural areas is also a hindrance in this regard. Objective: The objective of the present study was to evaluate the periodontal health status and treatment needs of hospitalized CP patients of rural Punjab. Methodology: Periodontal health status and treatment needs of hospitalized CP patients were determined by epidemiological indices. Questionnaires were filled by the patient's parents/attendants about the home-care oral hygiene measures and dietary habits of the patient. All patients were given nonsurgical periodontal therapy with reenforcement of oral hygiene measures as a part of our treatment plan. Results and Conclusion: From this study, it was concluded that periodontal disease is prevalent in hospitalized cerebral-palsied patients. Treatment needs for such patients include assisted oral health care, pain management, and constant psychosocial support. The inclusion of a dental healthcare professional in the management team would help improve the quality of life in these hospitalized cerebral-palsied patients.

Botulinum toxin in post-stroke patients, setting up a spasticity clinic: Experience and results

Spasticity is defined as a motor disorder characterized by a velocitydependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, spasticity results from hyperexcitability of the stretch reflex, one component of upper motor neuron syndrome. This may affect limb position and activities of daily living. Spasticity contributes to disability in post stroke patients with a frequency of 41.6%. Botulinum toxin is a neurotoxin that acts on the neuromuscular junction at the presynaptic site. It inhibits the release of acetylcholine, thus leading to muscle weakness and reduced muscle tone. Botulinum toxin treatment in post-stroke upper and lower limb spasticity is a safe and effective .Procedure to decrease muscle tone and increase the range of motion. Poststroke rehabilitation is important to reduce disability and Botulinum toxin type A injections is considered a gold, Standard treatment for focal spasticity.

Subcutaneous infiltration of doxylamine on cutaneous analgesia in rats.

We aimed to evaluate the effect of doxylamine, a first generation antihistamine, as a local analgesic agent by comparing its effect to bupivacaine. After blocking the cutaneous trunci muscle reflex (CTMR) by subcutaneous injection of doxylamine, we assessed doxylamine's cutaneous analgesic effect in rats. The dose-related effect and duration of doxylamine on infiltrative cutaneous analgesia were compared with that of bupivacaine. We demonstrated that doxylamine, as well as the local anesthetic bupivacaine produced the cutaneous analgesic effects in a dose-related fashion. At the equipotent dose (50% effective doses (ED50)), the relative potency was bupivacaine (0.41 (0.36-0.48) mmol)> doxylamine (7.39 (6.91-7.91)mmol) (p<0.01). On an equipotent basis (ED25, ED50 and ED75), subcutaneous doxylamine resulted in greater duration of action (p<0.01) than bupivacaine at producing cutaneous analgesia. The result of this experiment indicated that doxylamine has the local anesthetic property less potent than bupivacaine, but its nociceptive block duration is longer than that of bupivacaine at an equianalgesic dose.

Infant Neuromotor Development and Childhood Problem Behavior.

Research of adults and school-aged children suggest a neurodevelopmental basis for psychiatric disorders. We examined whether infant neuromotor development predicted internalizing and externalizing problems in young children. In Generation R, a population-based cohort in the Netherlands (2002-2006), trained research assistants evaluated the neuromotor development of 4006 infants aged 2 to 5 months by using an adapted version of Touwen's Neurodevelopmental Examination (tone, responses, and senses and other observations). We defined nonoptimal neuromotor development as scores in the highest tertile. Mothers and fathers rated their children's behavior at ages 1.5, 3, 6, and 10 years with the Child Behavior Checklist (n = 3474, response: 86.7%). The associations were tested with generalized linear mixed models. Overall, neuromotor development predicted internalizing scores, but no association was observed with externalizing scores. Nonoptimal muscle tone was associated with higher internalizing scores (mothers' report: β = .07; 95% confidence interval [CI]: 0.01 to 0.13; fathers' report: β = .09, 95% CI: 0.00 to 0.16). In particular, nonoptimal low muscle tone was associated with higher internalizing scores (mothers' report: β = .11; 95% CI: 0.05 to 0.18; fathers' report: β = .13; 95% CI: 0.04 to 0.22). We also observed an association between senses and other observations with internalizing scores. There was no relationship between high muscle tone or reflexes and internalizing scores. Common emotional problems in childhood have a neurodevelopmental basis in infancy. Neuromotor assessment in infancy may help identify vulnerability to early internalizing symptoms and offer the opportunity for targeted interventions.

Surgical Treatment of Spinal Synovial Cysts in Elderly Patients: Symptoms, Treatment Course, and Outcome in Patients >75 Years of Age.

With the aging of our society comes a rising number of elderly patients with progressive degeneration of the spine associated with synovial cysts. Surgical treatment may be particularly challenging in elderly patients because of comorbidities. Patients treated in our department between 1999 and 2014 for spinal synovial cysts were screened. The 28 patients ≥75 years old were classified as elderly and were compared with 96 patients 50-74 years old. No patient underwent fusion as part of cyst resection. Despite a significantly higher frequency of muscle reflex changes in elderly patients at presentation, symptoms, cyst levels, rate of complications, and surgical method were not different between groups. Cyst adherence to the dura and subtotal resection were observed significantly more often in the elderly group (18% vs. 3%; P < 0.05). Outcome according to the Oswestry Disability Index was classified as no disability or minimal disability in 85% of the elderly group and in 82% of the control group. Recurrent cyst and delayed fusion rates were lower in the elderly group (4% and 4%) compared with the control group (7% and 8%). The clinical course of elderly patients with surgical treatment of spinal synovial cysts did not differ compared with younger patients. Good or excellent results could be achieved and persisted for a long time in most cases. Fusion should be performed only in cases of severe instability. Nonaggressive cyst removal in cases of dural attachment enables low cerebrospinal fluid fistula rates without increasing cyst recurrence rates.