The strength of the patellar and Achilles tendon reflexes is not affected in uncomplicated pregnancy.

INTRODUCTION: Research on healthy pregnant women's reflexes is almost unheard of, even if an estimation of reflexes is a conventional part of the physical examination of preeclamptic patients, and hyperreflexia is generally considered to be a warning sign of eclampsia. The aim of the present study was to investigate the possible impact of gestation on tendon reflexes and the Babinski response, as examined in a clinical bed-side manner. MATERIAL AND METHODS: A prospective, single-blind, cross-sectional study. Three study groups comprised non-pregnant (n = 20), 14-18 weeks (n = 16), and 34-38 weeks (n = 15) healthy pregnant women respectively. Two experienced neurologists examined separately each participant's patellar reflexes, Achilles reflexes, and Babinski response and rated them on two different scales, National Institute of Neurological Disorders and Stroke (NINDS) scale and Mayo Clinic Scale for Tendon Reflex Assessment. Inter-observer estimations between the patient groups and the neurologists were made by mixed effect model methodology. RESULTS: The patellar and Achilles reflexes´ strengths were rated similarly in all three groups (p > 0.05). The inter-observer difference was non-significant between the neurologists´ estimations (p > 0.05). The neurologists estimated the Babinski response in a few cases as neutral (0), otherwise down (normal). CONCLUSIONS: The patellar and Achilles reflex strengths are not affected in uncomplicated pregnancy. There is good concordance between neurologists´ estimations of tendon reflex strengths rated on the NINDS and Mayo scales.

[Hereditary sensory and autonomic neuropathy 1E showing hyperreflexia: a case report].

A 52-year-old man had developed hearing loss since childhood, as well as recurrent foot ulcers and osteomyelitis since his forties. He presented with gait disturbance and dysarthria that had worsened over four years and a month, respectively. Neurological exams revealed cognitive impairment, proximal weakness of the lower extremities, generalized hyperrflexia, ataxia, sensory disturbances predominant in deep sensation, urinary retention, and gait instability. On nerve conduction study, no sensory nerve action potentials were evoked in the upper and lower limbs. Since his grandmother suffered from similar symptoms, we investigated genetic analysis, which revealed a missense mutation (c.1483T>C, p.Y495H) in DNA methyltransferase 1 gene. He was subsequently diagnosed with hereditary sensory and autonomic neuropathy 1E (HSAN1E). It is important to recognize that increased deep tendon reflex can be observed in HSAN1E.

Dominant mechanism in spinal cord injury-induced immunodeficiency syndrome (SCI-IDS): sympathetic hyperreflexia.

Clinical studies have shown that individuals with spinal cord injury (SCI) are particularly susceptible to infectious diseases, resulting in a syndrome called SCI-induced immunodeficiency syndrome (SCI-IDS), which is the leading cause of death after SCI. It is believed that SCI-IDS is associated with exaggerated activation of sympathetic preganglionic neurons (SPNs). After SCI, disruption of bulbospinal projections from the medulla oblongata C1 neurons to the SPNs results in the loss of sympathetic inhibitory modulation from the brain and brainstem and the occurrence of abnormally high levels of spinal sympathetic reflexes (SSR), named sympathetic hyperreflexia. As the post-injury survival time lengthens, mass recruitment and anomalous sprouting of excitatory interneurons within the spinal cord result in increased SSR excitability, resulting in an excess sympathetic output that disrupts the immune response. Therefore, we first analyze the structural underpinnings of the spinal cord-sympathetic nervous system-immune system after SCI, then demonstrate the progress in highlighting mechanisms of SCI-IDS focusing on norepinephrine (NE)/Beta 2-adrenergic receptor (ß2-AR) signal pathways, and summarize recent preclinical studies examining potential means such as regulating SSR and inhibiting ß2-AR signal pathways to improve immune function after SCI. Finally, we present research perspectives such as to promote the effective regeneration of C1 neurons to rebuild the connection of C1 neurons with SPNs, to regulate excitable or inhibitory interneurons, and specifically to target ß2-AR signal pathways to re-establish neuroimmune balance. These will help us design effective strategies to reverse post-SCI sympathetic hyperreflexia and improve the overall quality of life for individuals with SCI.

Corticospinal excitability after 5-day Dry Immersion in women.

In light of the development of manned astronautics and the increasing participation of women in space flights, the question of female body adaptation to microgravity conditions becomes relevant. Currently, one of the important directions in this issue is to study the effects of support withdrawal as a factor of weightlessness on the human sensorimotor system. Dry Immersion is one of the well-known ground-based models, which adequately reproduces the main physiological effects of space flight. The aim of this study was to evaluate the changes in motor evoked potentials of the lower leg gravity-dependent muscles in women after a 5-day Dry Immersion. We analyzed evoked responses to transcranial and trans-spinal magnetic stimulation. In this method, areas of interest (the motor cortex and lumbosacral thickening of the spinal cord) are stimulated with an electromagnetic stimulus. The experiment was conducted with the participation of 16 healthy female volunteers with a natural menstrual cycle. The thresholds, amplitudes, and latencies of motor potentials evoked by magnetic stimulation were assessed. We showed that 5-day exposure to support withdrawal leads to a decrease in motor-evoked potential thresholds and central motor conduction time, although changes in motor response amplitudes were ambiguous. The data obtained correspond to the results of previous research on Dry Immersion effects on the sensorimotor system in men.

Partial atlantooccipital assimilation causing atlantoaxial instability and early myelopathy in an adult treated with occipitocervical fusion: A case report.

INTRODUCTION & IMPORTANCE: Atlanto-occipital assimilation is a rare congenital abnormality which can cause atlantoaxial instability. Basilar invagination and instability can lead to cord compression and myelopathy in young individuals. CASE REPORT & DISCUSSION: A 37-year-old male presented with gradually worsening axial neck pain for four years duration His deep tendon reflexes are exaggerated in all four limbs but there is no weakness or imbalance. Following radiological evaluation, he was diagnosed to have partial atlantooccipital assimilation causing atlantoaxial instability, basilar invagination and early myelopathy. He was treated with occipital-cervical fusion after the closed reduction of the atlantoaxial joint. CONCLUSION: Atlanto-axial assimilation can lead to atlantoaxial instability and subsequently myelopathy. Dynamic radiographs and computed tomography are helpful in the diagnosis. Reducible atlantoaxial instability can be managed with closed reduction and occipitocervical fusion.

Dysfunctional neuro-muscular mechanisms explain gradual gait changes in prodromal spastic paraplegia.

BACKGROUND: In Hereditary Spastic Paraplegia (HSP) type 4 (SPG4) a length-dependent axonal degeneration in the cortico-spinal tract leads to progressing symptoms of hyperreflexia, muscle weakness, and spasticity of lower extremities. Even before the manifestation of spastic gait, in the prodromal phase, axonal degeneration leads to subtle gait changes. These gait changes - depicted by digital gait recording - are related to disease severity in prodromal and early-to-moderate manifest SPG4 participants. METHODS: We hypothesize that dysfunctional neuro-muscular mechanisms such as hyperreflexia and muscle weakness explain these disease severity-related gait changes of prodromal and early-to-moderate manifest SPG4 participants. We test our hypothesis in computer simulation with a neuro-muscular model of human walking. We introduce neuro-muscular dysfunction by gradually increasing sensory-motor reflex sensitivity based on increased velocity feedback and gradually increasing muscle weakness by reducing maximum isometric force. RESULTS: By increasing hyperreflexia of plantarflexor and dorsiflexor muscles, we found gradual muscular and kinematic changes in neuro-musculoskeletal simulations that are comparable to subtle gait changes found in prodromal SPG4 participants. CONCLUSIONS: Predicting kinematic changes of prodromal and early-to-moderate manifest SPG4 participants by gradual alterations of sensory-motor reflex sensitivity allows us to link gait as a directly accessible performance marker to emerging neuro-muscular changes for early therapeutic interventions.

Physical Signs and Clinical Features of Cervical Myelopathy in Elderly Patients, Especially 80 Years or Older: Comparison of 100 Consecutive Operative Cases across Three Age Groups.

STUDY DESIGN: Retrospective cohort study. PURPOSE: The present study aimed to examine the characteristics of physical signs in elderly patients with cervical myelopathy (CM) and to compare the findings in three different age groups. OVERVIEW OF LITERATURE: As the global population ages, the incidence of CM in elderly patients is increasing. METHODS: We evaluated 100 consecutive surgical patients with CM and divided them into the following groups: 80s (34 patients; mean age, 83.9 years), 70s (33 patients; mean age, 73.9 years), and 69 or younger (33 patients; mean age, 60.9 years). The clinical symptoms and physical signs were evaluated and recorded. RESULTS: Although the recovery rate decreased with increasing age, all groups demonstrated a significant improvement in clinical symptoms relative to preoperative values. The Hoffman sign and hyperreflexia of the triceps tendon were, respectively, present in 82% and 88% of patients in the 80s group, 74% and 64% of those in the 70s group, and 69% and 82% of those in the 69 or younger group, with no significant difference among the groups. In contrast, the rates of hyperreflexia of the patellar and Achilles tendons were, respectively, 59% and 32% in the 80s group, 85% and 48% in the 70s group, and 91% and 70% in the 69 or younger group, with significant differences. CONCLUSIONS: The positivity rate of the lower extremity hyperreflexia decreased significantly with increasing age in patients with CM. The absence of hyperreflexia, particularly lower extremity, is not uncommon in elderly patients with suspected CM.

Panhypopituitarism and Central Hypothyroidism Presenting as Myoclonus and Hyperreflexia.

Panhypopituitarism may present with symptoms of predominantly one or more hormonal deficiencies. Central hypothyroidism usually presents with typical symptoms of hypothyroidism, such as fatigue, weight gain, menstrual abnormalities, bradycardia, thick, coarse skin, muscle fasciculations, and hyporeflexia, among others. Herein we present a case of central hypothyroidism along with panhypopituitarism presenting with unusual symptoms of tongue fasciculation, hyperreflexia, and myoclonic jerks.

Combined tendon reflex and motor evoked potential recordings in amyotrophic lateral sclerosis.

OBJECTIVE: This retrospective (case-control) collaborative study evaluates tendon reflex recordings combined with transcranial magnetic stimulation motor evoked potentials recordings (T-MEPs) at lower limbs in amyotrophic lateral sclerosis (ALS). METHODS: T-MEPs were recorded in 97 ALS patients distinguished according to their patellar reflex briskness. Patients' electrophysiological data were compared with values measured in 60 control patients matched for age and height. Correlations studies between parameters or with some patients' clinical characteristics were also performed. RESULTS: The central motor conduction time yields the highest sensitivity (82%) and specificity (93%), allowing twice more upper motor neuron (UMN) dysfunction detection than clinical examination, and being more altered in late stages of the disease. The T response to MEP response amplitude ratio (T/MEP ar) is nearly as sensitive to detect ALS and better identifies abnormal hyperreflexia. It is not correlated with evolutive stage, contrarily to conduction time-related parameters. In addition, T-MEPs detect asymmetries escaping clinical examination. CONCLUSIONS: The corticospinal conduction to lower limbs is slowed in ALS. The T/MEP ar helps deciding when patellar reflexes are abnormal in a given patient suspected of ALS. SIGNIFICANCE: The T-MEP technique provide powerful electrophysiological biomarkers of UMN involvement in ALS. This simple and painless procedure introduces the clinically useful concept of electrophysiological hyperreflexia and might be expanded to future exploration of proximal upper limbs and bulbar territories.

Altered cutaneous reflexes to non-noxious stimuli in the triceps surae of people with chronic incomplete spinal cord injury.

Following spinal cord injury (SCI) task-dependent modulation of spinal reflexes are often impaired. To gain insight into the state of the spinal interneuronal pathways following injury, we studied the amplitude modulation of triceps surae cutaneous reflexes to non-noxious stimuli during standing and early-to-mid stance phase of walking in participants with and without chronic incomplete SCI. Reflex eliciting nerve stimulation was delivered to the superficial peroneal, sural, and distal tibial nerves about the ankle. Reflexes were analyzed in the short (SLR, 50-80 ms post stimulation onset) and the medium (MLR, 80-120 ms) latency response windows. Further, the relation between cutaneous and H-reflexes was also examined during standing. In participants without injuries the soleus SLR was modulated task-dependently with nerve specificity, and the soleus and medial gastrocnemius MLRs were modulated task-dependently. In contrast, participants with SCI, no task-dependent or nerve-specific modulation of triceps cutaneous reflexes was observed. The triceps surae cutaneous and H-reflexes were not correlated in either group (r = 0.01-0.37). The presence of cutaneous reflexes but the absence of significant amplitude modulation may suggest impaired function of spinal interneuronal pathways in this population. The lack of correlation between the cutaneous and H-reflexes may suggest that interneurons that are involved in H-reflex modulation and cutaneous reflex modulation do not receive common input, or the impact of the common input is outweighed by other input. Present findings highlight the importance of examining multiple spinal reflexes to better understanding spinal interneuronal pathways that affect motor control in people after SCI.

Delayed viral vector mediated delivery of neurotrophin-3 improves skilled hindlimb function and stability after thoracic contusion.

Intramuscular injection of an Adeno-associated viral vector serotype 1 (AAV1) encoding Neurotrophin-3 (NT3) into hindlimb muscles 24 h after a severe T9 spinal level contusion in rats has been shown to induce lumbar spinal neuroplasticity, partially restore locomotive function and reduce spasms during swimming. Here we investigate whether a targeted delivery of NT3 to lumbar and thoracic motor neurons 48 h following a severe contusive injury aids locomotive recovery in rats. AAV1-NT3 was injected bilaterally into the tibialis anterior, gastrocnemius and rectus abdominus muscles 48-h following trauma, persistently elevating serum levels of the neurotrophin. NT3 modestly improved trunk stability, accuracy of stepping during skilled locomotion, and alternation of the hindlimbs during swimming, but it had no effect on gross locomotor function in the open field. The number of vGlut1+ boutons, likely arising from proprioceptive afferents, on gastrocnemius α-motor neurons was increased after injury but normalised following NT3 treatment, suggestive of a mechanism in which functional benefits may be mediated through proprioceptive feedback. Ex vivo MRI revealed substantial loss of grey and white matter at the lesion epicentre but no effect of delayed NT3 treatment to induce neuroprotection. Lower body spasms and hyperreflexia of an intrinsic paw muscle were not reliably induced in this severe injury model suggesting a more complex anatomical or physiological cause to their induction. We have shown that delayed intramuscular AAV-NT3 treatment can promote recovery in skilled stepping and coordinated swimming, supporting a role for NT3 as a therapeutic strategy for spinal injuries potentially through modulation of somatosensory feedback.

Revising the stretch reflex threshold method to measure stretch hyperreflexia in cerebral palsy.

Hyper-resistance is an increased resistance to passive muscle stretch, a common feature in neurological disorders. Stretch hyperreflexia, an exaggerated stretch reflex response, is the neural velocity-dependent component of hyper-resistance, and has been quantitatively measured using the stretch reflex threshold (i.e., joint angle at the stretch reflex electromyographic onset). In this study, we introduce a correction in how the stretch reflex threshold is calculated, by accounting for the stretch reflex latency (i.e., time between the stretch reflex onset at the muscle spindles and its appearance in the electromyographic signal). Furthermore, we evaluated how this correction affects the stretch reflex threshold in children and young adults with spastic cerebral palsy. A motor-driven ankle dynamometer induced passive ankle dorsiflexions at four incremental velocities in 13 children with cerebral palsy (mean age: 13.5 years, eight males). The stretch reflex threshold for soleus and medial gastrocnemius muscles was calculated as 1) the joint angle corresponding to the stretch reflex electromyographic onset (i.e., original method); and as 2) the joint angle corresponding to the electromyographic onset minus the individual Hoffmann-reflex latency (i.e., latency corrected method). The group linear regression slopes between stretch velocity and stretch reflex threshold differed in both muscles between methods (p < 0.05). While the original stretch reflex threshold was velocity dependent in both muscles (p < 0.05), the latency correction rendered it velocity independent. Thus, the effects of latency correction on the stretch reflex threshold are substantial, especially at higher stretch velocities, and should be considered in future studies.

Riluzole and Edavarone: The Hope Against Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is one of the most frequent motor neuron illnesses. Motor neuron illnesses are various disorders that include upper and lower motor neuron abnormalities. Amyotrophic lateral sclerosis accounts for roughly 80% of motor neuron disorders. ALS is a fatal motor neuron disease that involves the loss of motor neurons in the spinal cord and brain, resulting in gliosis and muscle weakening and wasting in the upper, lower, and respiratory muscles, reducing life expectancy to 2-5 years from the onset of symptoms. Up until now, oral riluzole, a glutamatergic neurotransmitter inhibitor, has been used to manage ALS, the only drug for the management of ALS that has been approved by the United States (US) Food and Drug Administration (FDA). In recent studies, edaravone has been used through intravenous mode to halt the progression of ALS. We conducted a systematic search on PubMed; we selected Google Scholar, PubMed, websites regarding ALS, WebMD, Researchgate, als.org, consultant360, and the relevant articles for the review. It shows us riluzole and edaravone's efficacy for managing A.L.S. and how it can increase the life span of the patients.

Autonomic Dysreflexia following Spinal Cord Injury.

Autonomic dysreflexia (AD) is a potentially life-threatening condition of the autonomic nervous system following spinal cord injury at or above T6. One of the most common symptoms is a sudden increase in blood pressure induced by afferent sensory stimulation owing to unmodulated reflex sympathetic hyperactivity. Such episodes of high blood pressure might be associated with a high risk of cerebral or retinal hemorrhage, seizures, heart failure, or pulmonary edema. In-depth knowledge is, therefore, crucial for the proper management of the AD, especially for spine surgeons, who encounter these patients quite often in their clinical practice. Systematical review of the literature dealing with strategies to prevent and manage this challenging condition was done by two independent reviewers. Studies that failed to assess primary (prevention, treatment strategies and management) and secondary outcomes (clinical symptomatology, presentation) were excluded. A bibliographical search revealed 85 eligible studies that provide a variety of preventive and treatment measures for the subjects affected by AD. As these measures are predominantly based on noncontrolled trials, long-term prospectively controlled multicenter studies are warranted to validate these preventive and therapeutic proposals.

Case Report: Anesthetic Management of Cesarean Section in a Patient With Paraplegia.

Background: With the advancement of medical science and rehabilitative care, more women with spinal cord injury (SCI) can conceive. However, autonomic hyperreflexia due to SCI complicates anesthesia management during cesarean sections. Case Presentation: This study reports the anesthesia management in a woman with paraplegia with a T6 SCI lesion who underwent a cesarean section. It also reviews the anesthesia strategies used in other studies. Spinal anesthesia with a low concentration of ropivacaine was administered along with dexmedetomidine for sedation. Stable hemodynamics were achieved without complications. Conclusions: Based on the reported case and literature review, we conclude that the intrathecal block is the preferred choice for women with paraplegia who require cesarean section if the lumbar bone structure allows puncture attempts.

Spasticity Management after Spinal Cord Injury: The Here and Now.

Spasticity is a common comorbidity of spinal cord injury (SCI) that is characterized by velocity dependent tone and spasms manifested by uninhibited reflex activity of muscles below the level of injury. For some, spasticity can be beneficial and facilitate functional standing, transfers, and some activities of daily living. For others, it may be problematic, painful, and interfere with mobility and function. This manuscript will address the anatomy and physiology of neuromuscular reflexes as well as the pathophysiology that occurs after SCI. Spasticity assessment will be discussed in terms of clinical history and findings on physical examinations, including responses to passive and active movement, deep tendon reflexes, and other long tract signs of upper motor neuron injury, as well as gait and function. Management strategies will be discussed including stretch, modalities, pharmacotherapy, neurolysis, and surgical options.

Characterizing the Experience of Spasticity after Spinal Cord Injury: A National Survey Project of the Spinal Cord Injury Model Systems Centers.

OBJECTIVE: To characterize the qualities that individuals with spinal cord injury (SCI) associate with their experience of spasticity and to describe the relationship between spasticity and perceived quality of life and the perceived value of spasticity management approaches. DESIGN: Online cross-sectional survey. SETTING: Multicenter collaboration among 6 Spinal Cord Injury Model Systems hospitals in the United States. PARTICIPANTS: Individuals with SCI (N=1076). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Qualities of Spasticity Questionnaire, modified Spinal Cord Injury-Spasticity Evaluation Tool (mSCI-SET), and the modified Patient-Reported Impact of Spasticity Measure (mPRISM). RESULTS: Respondents indicated that spasms most often occurred in response to movement-related triggering events. However, spontaneous spasms (ie, no triggering event) were also reported to be among the most common types. Frequency of spasms appears to decline with age. The highest frequency of spasms was reported by 56% of respondents aged <25 years and by only 28% of those >55 years. Stiffness associated with spasticity was reported to be more common than spasms (legs, 65% vs 54%; trunk, 33% vs 18%; arms, 26% vs 15%). Respondents reported negative effects of spasticity more commonly than positive effects. Based on their association with negative scores on the mSCI-SET and the mPRISM, the 5 most problematic experiences reported were stiffness all day, interference with sleep, painful spasms, perceived link between spasticity and pain, and intensification of pain before a spasm. Respondents indicated spasticity was improved more by stretching (48%) and exercise (45%) than by antispasmodics (38%). CONCLUSIONS: The experience of spasticity after SCI is complex and multidimensional, with consequences that affect mobility, sleep, comfort, and quality of life. Stiffness, rather than spasms, appears to be the most problematic characteristic of spasticity. Physical therapeutic interventions to treat spasticity warrant in-depth investigation.

Functional assessment of stretch hyperreflexia in children with cerebral palsy using treadmill perturbations.

BACKGROUND: As hyperactive muscle stretch reflexes hinder movement in patients with central nervous system disorders, they are a common target of treatment. To improve treatment evaluation, hyperactive reflexes should be assessed during activities as walking rather than passively. This study systematically explores the feasibility, reliability and validity of sudden treadmill perturbations to evoke and quantify calf muscle stretch reflexes during walking in children with neurological disorders. METHODS: We performed an observational cross-sectional study including 24 children with cerebral palsy (CP; 6-16 years) and 14 typically developing children (TD; 6-15 years). Short belt accelerations were applied at three different intensities while children walked at comfortable speed. Lower leg kinematics, musculo-tendon lengthening and velocity, muscle activity and spatiotemporal parameters were measured to analyze perturbation responses. RESULTS: We first demonstrated protocol feasibility: the protocol was completed by all but three children who ceased participation due to fatigue. All remaining children were able to maintain their gait pattern during perturbation trials without anticipatory adaptations in ankle kinematics, spatiotemporal parameters and muscle activity. Second, we showed the protocol's reliability: there was no systematic change in muscle response over time (P = 0.21-0.54) and a bootstrapping procedure indicated sufficient number of perturbations, as the last perturbation repetition only reduced variability by ~ 2%. Third, we evaluated construct validity by showing that responses comply with neurophysiological criteria for stretch reflexes: perturbations superimposed calf muscle lengthening (P < 0.001 for both CP and TD) in all but one participant. This elicited increased calf muscle activity (359 ± 190% for CP and 231 ± 68% for TD, both P < 0.001) in the gastrocnemius medialis muscle, which increased with perturbation intensity (P < 0.001), according to the velocity-dependent nature of stretch reflexes. Finally, construct validity was shown from a clinical perspective: stretch reflexes were 1.7 times higher for CP than TD for the gastrocnemius medialis muscle (P = 0.017). CONCLUSIONS: The feasibility and reliability of the protocol, as well as the construct validity-shown by the exaggerated velocity-dependent nature of the measured responses-strongly support the use of treadmill perturbations to quantify stretch hyperreflexia during gait. We therefore provided a framework which can be used to inform clinical decision making and treatment evaluation.

Can tendon reflexes be elicited by both stretch and vibration in man?

AIM OF STUDY: When the biceps tendon is tapped, a contraction is elicited in the biceps muscle. This also occurs with tapping of the radial bone, and it has been suggested that vibration is a stimulus for deep tendon reflexes. We investigated whether the normal stimulus for the deep tendon reflex is a sudden stretch, a phasic vibration, or both. Furthermore, we investigated the importance of forearm position for the reflex response in controls and stroke patients. METHODS: We investigated 50 neurological outpatients without clinical signs of neurological disorders in the arms. The biceps tendon and distal radius were tapped with the forearm in the midway (90°), supinated, and pronated positions. In 10 of these patients, the two reflexes were also investigated with quantitative electromyography (EMG) measurements in the 3 positions. Another 10 patients were investigated clinically when stretch of elbow was eliminated and 17 patients were examined when prestretching of the biceps tendon was avoided. Finally, we examined 32 patients that had experienced stroke. RESULTS: In 94% (47/50) of patients, after a radial tap, the biceps contraction disappeared in the supinated forearm, and the median peak-to-peak amplitude of the surface EMG response (n = 10) decreased from 1.1 to 0.2 mV (p < .01). Elimination of elbow stretch as well as pressure on the biceps tendon did not change the reflex response. In 84% (27/32) of stroke patients, after a radial tap, the biceps contraction persisted in supination in the arm with hyperreflexia. CONCLUSION: The combined clinical and EMG results are consistent with the concept that the deep tendon reflexes in man can be elicited by both stretch and phasic vibration. Clinicians should be aware that the brachioradial reflex depends on the forearm position.