The deep tendon and the abdominal reflexes

Does the patellar tendon reflex affect the postural stability in stroke patients with blocked vision?

Background

Stroke patients often show postural instability. The patellar tendon reflex is a basic physical examination for stroke patients. This study aimed to explore the correlation between patellar tendon reflex grade and postural stability among stroke patients.

Methods

A total of 37 elderly stroke patients, each with the same quadriceps muscle strength but different patellar tendon reflex levels, were tested on a force platform under eyes-open (EO) and eyes-closed (EC) conditions. Parametric analysis, detrended fluctuation analysis (DFA), and power spectral density (PSD) analysis were used in centre of pressure (COP) signal processing. The correlation between the results of measured data processing and the level of patellar tendon reflex was analysed.

Results

All three parameters of COP (the length of the sway trajectory, the mean range of the sway trajectory in the mediolateral [ML] direction [R _x ], and the mean range of the sway trajectory in the anterior-posterior [AP] directions [R _y ]) were negatively correlated with the patient's patellar tendon reflex grade under the EC condition. The DFA results showed that a higher grade of patellar tendon reflex was associated with a smaller value of the crossover point in the AP direction. Only the PSD values of each frequency band in the AP direction were negatively correlated with patellar tendon reflex grade with EO and became negatively correlated in both AP and ML directions with EC. Overall, the results showed a strong correlation between patellar tendon reflex and postural stability in stroke patients when vision was blocked.

Significance

The strong correlation with EC may provide insights into clinic evaluation and treatment for rehabilitation or fall risks of stroke patients.

Longitudinal Effects of Asymptomatic C9orf72 Carriership on Brain Morphology

OBJECTIVE

We investigated effects of C9orf72 repeat expansion and gene expression on longitudinal cerebral changes before symptom onset.

METHODS

We enrolled 79 asymptomatic family members (AFMs) from 9 families with C9orf72 repeat expansion. Twenty-eight AFMs carried the mutation (C9+). Participants had up to 3 magnetic resonance imaging (MRI) scans, after which we compared motor cortex and motor tracts between C9+ and C9- AFMs using mixed effects models, incorporating kinship to correct for familial relations and lessen effects of other genetic factors. We also compared cortical, subcortical, cerebellar, and connectome structural measurements in a hypothesis-free analysis. We correlated regional C9orf72 expression in donor brains with the pattern of cortical thinning in C9+ AFMs using meta-regression. For comparison, we included 42 C9+ and 439 C9- patients with amyotrophic lateral sclerosis (ALS) in this analysis.

RESULTS

C9+ AFM motor cortex had less gyrification and was thinner than in C9- AFMs, without differences in motor tracts. Whole brain analysis revealed thinner cortex and less gyrification in parietal, occipital, and temporal regions, smaller thalami and right hippocampus, and affected frontotemporal connections. Thinning of bilateral precentral, precuneus, and left superior parietal cortex was faster in C9+ than in C9- AFMs. Higher C9orf72 expression correlated with thinner cortex in both C9+ AFMs and C9+ ALS patients.

INTERPRETATION

In asymptomatic C9orf72 repeat expansion carriers, brain MRI reveals widespread features suggestive of impaired neurodevelopment, along with faster decline of motor and parietal cortex than found in normal aging. C9orf72 expression might play a role in cortical development, and consequently explain the specific brain abnormalities of mutation carriers. ANN NEUROL 2022.

Atypical knee jerk responses in high-risk children: A longitudinal EMG-study

INTRODUCTION

We previously found that atypical responses to the knee jerk reflex, i.e., tonic responses (TRs), clonus and contralateral responses in very high-risk (VHR) infants were associated with cerebral palsy (CP) at 21 months. The current study aimed for a better understanding of pathophysiology of atypical knee jerk responses by evaluating whether infant atypical knee jerk responses are associated with CP and atypical knee jerk responses at school-age.

METHODS

31 VHR-children, who had also been assessed longitudinally during infancy, and 24 typically developing children, were assessed at 7-10 years (school-age). We continuously recorded surface EMG of thigh muscles during knee jerk responses longitudinally during infancy and once at school-age. Neurological condition was assessed with age-appropriate neurological examinations. It included the diagnosis of CP at 21 months corrected age and school-age. CP's type and severity (Gross Motor Function Classification System (GMFCS)) were reported.

RESULTS

Persistent TRs in infancy were associated with CP at school-age. TR prevalence decreased from infancy to childhood. At school-age it was no longer associated with CP. Clonus prevalence in VHR-children did not change with increasing age; it was significantly higher in children without than those with CP. Reflex irradiation was common in all school-age children, and its prevalence in contralateral muscles in VHR-children decreased between infancy and childhood.

CONCLUSIONS

In infancy, TRs indicated an increased risk of CP, but at school-age TRs were not associated with CP. In general, spinal hyperexcitability, expressed as reflex irradiation and TRs, decreased between infancy and school-age.

PASTEC - a prospective, single-center, randomized, cross-over trial of pure physical versus physical plus attentional training in children with cancer

Despite recent improvements in survival rates in children with cancer, long-term toxicities remain a major concern. Physical activity could reduce the impact of long-term sequelae, notably in neuropsychological and physical areas. We report of a randomized trial of pure physical versus physical/attentional training in pediatric oncology patients. Twenty-two patients aged 6-18 y.o. were included, irrespective of their clinical diagnosis or treatment status, stratified by age and randomized 1:1 into pure physical vs. physical/attentional activity arms, with a cross-over at study midpoint. Neurological, motor and neuropsychological assessments were performed at inclusion, start, crossover and end of the program. Feasibility, defined as > 80% patients attending > 80% of sessions, was the primary endpoint. Secondary outcomes were improvements in neuropsychological and motor performance tests. While 68% of patients attended more than 80% of sessions during the pre-crossover phase of the study, this dropped to 36% post-crossover. Our study therefore failed to meet our primary endpoint. Nonetheless, significant improvements in anxiety (p<0.001), emotional control (p = 0.04), organization skills (p = 0.03), as well as motor deficit scores (p = 0.04) were observed. We noted no significant difference between the pure physical and the physical/attentional training arms, or when analyzing subgroups by age or sequence of intervention. We conclude that physical activity has a positive impact on anxiety, emotional and organizational aspects as well as motor deficits. Attendance dropped during the course of the study and motivational interventions should be included in future studies or equivalent programs.Supplemental data for this article is available online at https://doi.org/10.1080/08880018.2021.1994677 .

Onset of Action of Bupivacaine Administered via Dural Puncture Epidural versus Spinal, Lumbosacral, and Sacrococcygeal Epidural Injections in Dogs: Randomised Clinical Trial

Simple Summary

Epidural anaesthesia is commonly performed to provide long-lasting local anaesthesia in animals. Spinal anaesthesia has become popular in human anaesthesia due to a faster onset, but shorter duration, than epidural anaesthesia. Recently, dural puncture epidural anaesthesia (DPE) has been proposed as a compromise between spinal and epidural anaesthesia, providing longer duration than spinal anaesthesia with similar onset of action. This study aimed to compare the technical aspects of these techniques (onset of action, number of attempts, and time to perform them). The results showed no difference between the techniques in number of attempts required, while the epidural injections tended to be shorter than spinal and dural puncture epidural injections. The onset of action (measured as disappearance of the patellar reflex) was longer in the sacrococcygeal epidural injection than any other techniques (including lumbosacral epidural injections).

Abstract

The study aimed to compare bupivacaine onset time when administered via epidural anaesthesia injecting both at the lumbosacral and sacrococcygeal spaces, spinal anaesthesia, and DPE in clinical dogs. A total of 41 dogs requiring neuraxial anaesthesia as part of their anaesthetic protocol were recruited. They were randomly allocated to receive an epidural injection in the sacrococcygeal space aided by the nerve stimulator (SCO), an epidural injection in the lumbosacral (LS), a subarachnoid injection (SPI), or a DPE. The onset of anaesthesia was assessed every 30 s after the injection by testing the presence of patellar ligament reflex. The number of attempts and time to perform the technique were also recorded. Data were analysed using a one-way ANOVA for trimmed means with post hoc Lincoln test and a Kaplan–Meier curve. The significance level was set at p < 0.05, and the results are presented in absolute values and median (range). There was no difference in the number of attempts required to complete the techniques between groups (p = 0.97). Epidural injections (LS and SCO) tended to be shorter than SPI and DPE techniques, but there was no statistically significant difference (p = 0.071). The time to the disappearance of patellar ligament reflex (Westphal’s sign) in the SCO group was longer than in any other group. In conclusion, all techniques provided a rapid block of the patellar reflex. The SCO technique was the slowest in onset, while the other groups (SPI, DPE, and LS) were faster and almost indistinguishable.

Superficial abdominal reflexes

The superficial abdominal reflexes are often omitted from neurological examination, but their absence or asymmetry may support a lesion involving the thoracic spinal cord, especially in young, nulliparous and thin people.

Spinal reflexive movement follows general tau theory

Background

Tau theory explains how both intrinsically and perceptually guided movements are controlled by the brain. According to general tau theory, voluntary, self-paced human movements are controlled by coupling the tau of the movement (i.e., the rate of closure of the movement gap at its current closure rate) onto an intrinsically generated tau-guide (Lee in Ecol Psychol 10:221–250, 1998). To date there are no studies that have looked at involuntary movements, which are directly guided by innate patterns of neural energy generated at the level of the spinal cord or brain, and that can be explained by general tau theory. This study examines the guidance of an involuntary movement generated by the Patellar reflex in presence of a minimized gravitational field.

Results

The results showed that the Patellar reflexive movement is strongly coupled to an intrinsic tau-guide particularly when the limb is not moving in the direction of gravity.

Conclusion

These results suggest that the same principles of control underpin both voluntary and involuntary movements irrespective of whether they are generated in the brain or the spinal cord. Secondly, given that movements like the patellar reflex are visible from infancy, one might conclude that tau-guidance is an innate form of motor control, or neural blueprint, that has evolved over time.

Spinal Cord Anatomy and Localization

PURPOSE OF REVIEW

This article focuses on clinically relevant teaching points in spinal anatomy and localizing the lesion in myelopathy.

RECENT FINDINGS

The principles underlying spinal cord lesion localization are well established, but improvements in MRI and the discovery of pathologic antibodies associated with causes of transverse myelitis distinct from multiple sclerosis, such as aquaporin-4 IgG and myelin oligodendrocyte glycoprotein IgG, have assisted in diagnosis.

SUMMARY

The spinal cord has a highly organized neuroanatomy of ascending and descending tracts that convey sensory, motor, and autonomic information. Using integration of clues from the patient's history and neurologic examination, the effective clinician can distinguish spinal cord from peripheral nerve or brain pathology, often determine the level and parts of the spinal cord affected by a lesion, and focus on a likely diagnosis. The advent of MRI of the spine has revolutionized investigation of spinal cord disorders, but an important place for strong clinical acumen still exists in assessing the patient with a myelopathy.

Quantification of patellar tendon reflex using portable mechanomyography and electromyography devices

Deep tendon reflexes are one of the main components of the clinical nervous system examinations. These assessments are inexpensive and quick. However, evaluation can be subjective and qualitative. This study aimed to objectively evaluate hyperreflexia of the patellar tendon reflex using portable mechanomyography (MMG) and electromyography (EMG) devices. This study included 10 preoperative patients (20 legs) who had a pathology that could cause bilateral patellar tendon hyperreflexia and 12 healthy volunteers (24 legs) with no prior history of neurological disorders. We attached MMG/EMG sensors onto the quadriceps and tapped the patellar tendon with maximal and constant force. Our results showed a significantly high amplitude of the root mean square (RMS) and low frequency of the mean power frequency (MPF) in the rectus femoris, vastus medialis, and vastus lateralis muscles in both EMG and MMG with both maximal and constant force. Especially in the patients with cervical and thoracic myelopathy, the receiver operating characteristic (ROC) curve for diagnosing hyperreflexia of the patellar tendon showed a moderate to very high area under the curve for all EMG–RMS, EMG–MPF, MMG–RMS, and MMG–MPF values. The use of EMG and MMG for objectively quantifying the patellar tendon reflex is simple and desirable for future clinical applications and could help diagnose neurological disorders.

Central motor conduction time reveals upper motor neuron involvement masked by lower motor neuron impairment in a significant portion of patients with amyotrophic lateral sclerosis

OBJECTIVE

We retrospectively investigated the utility of the central motor conduction time (CMCT) in detecting upper motor neuron (UMN) involvements in patients with amyotrophic lateral sclerosis (ALS).

METHODS

Fifty-two ALS patients and 12 disease control patients participated in this study. Surface electromyograms were recorded from the first dorsal interosseous (FDI) and tibialis anterior (TA) muscles. We stimulated the motor cortex, brainstem, and spinal nerve using transcranial magnetic stimulation (TMS) in order to measure the cortical, brainstem, and spinal latencies. We divided the ALS patients into 2 subgroups (with UMN impairment vs. without UMN impairment) and calculated the rates of abnormal CMCT prolongation judged by their comparison with the normal ranges obtained by the measurement in the control patients.

RESULTS

The CMCTs in the FDI and TA were abnormally prolonged in over 40% of the ALS patients with UMN impairment and in nearly 30% of those without UMN impairment.

CONCLUSIONS

CMCT shows UMN dysfunction in ALS patients without clinical UMN impairment.

SIGNIFICANCE

TMS still has diagnostic utility in a significant portion of ALS patients.

Hyper-reflexia in Guillain-Barré syndrome: systematic review

Areflexia or hyporeflexia is a mandatory clinical criterion for the diagnosis of Guillain-Barré syndrome (GBS). A systematic review of the literature from 1 January 1993 to 30 August 2019 revealed 44 sufficiently detailed patients with GBS and hyper-reflexia, along with one we describe. 73.3% of patients were from Japan, 6.7% from the USA, 6.7% from India, 4.4% from Italy, 4.4% from Turkey, 2.2% from Switzerland and 2.2% from Slovenia, suggesting a considerable geographical variation. Hyper-reflexia was more frequently associated with antecedent diarrhoea (56%) than upper respiratory tract infection (22.2%) and the electrodiagnosis of acute motor axonal neuropathy (56%) than acute inflammatory demyelinating polyneuropathy (4.4%). Antiganglioside antibodies were positive in 89.7% of patients. Hyper-reflexia was generalised in 90.7% of patients and associated with reflex spread in half; it was present from the early progressive phase in 86.7% and disappeared in a few weeks or persisted until 18 months. Ankle clonus or Babinski signs were rarely reported (6.7%); spasticity never developed. 53.3% of patients could walk unaided at nadir, none needed mechanical ventilation or died. 92.9% of patients with limb weakness were able to walk unaided within 6 months. Electrophysiological studies showed high soleus maximal H-reflex amplitude to maximal compound muscle action potential amplitude ratio, suggestive of spinal motoneuron hyperexcitability, and increased central conduction time, suggestive of corticospinal tract involvement, although a structural damage was never demonstrated by MRI. Hyper-reflexia is not inconsistent with the GBS diagnosis and should not delay treatment. All GBS variants and subtypes can present with hyper-reflexia, and this eventuality should be mentioned in future diagnostic criteria for GBS.

Comparison of interobserver agreement between the evaluation of bicipital and the patellar tendon reflex in healthy dogs

The reliability of reflex-assessment is currently debatable, with current literature regarding the patellar tendon reflex (PTR) as highly reliable, while the biceps tendon reflex (BTR) is regarded to be of low reliability in the dog. Such statements are, however, based on subjective observations rather than on an empirical study. The goals of this study were three-fold: (1) the quantification of the interobserver agreement (IA) on the evaluation of the canine bicipital (BTR) and patellar tendon (PTR) reflex in healthy dogs, (2) to compare the IA of the BTR and PTR evaluation and (3) the identification of intrinsic (sex, age, fur length, weight) and extrinsic (observer´s expertise, body side) risk factors on the IA of both reflexes. The observers were subdivided into three groups based on their expected level of expertise (neurologists = highest -, practitioners = middle–and veterinary students = lowest level of expertise). For the BTR, 54 thoracic limbs were analyzed and compared to the evaluation of the PTR on 64 pelvic limbs. Each observer had to evaluate the reflex presence (RP) (present or absent) and the reflex activity (RA) using a 5-point ordinal scale. Multiple reliability coefficients were calculated. The influence of the risk factors has been calculated using a mixed regression-model. The Odds Ratio for each factor was presented. The higher the level of expertise the higher was the IA of the BTR. For RP(BTR), IA was highest for neurologists and for RA(BTR) the IA was lowest for students. The level of expertise had a significant impact on the degree of the IA in the evaluation of the bicipital tendon reflex: for the RA(BTR), practitioners had a 3.4-times (p = 0.003) and students a 7.0-times (p < 0.001) higher chance of discordance. In longhaired dogs the chance of disagreement was 2.6-times higher compared to shorthaired dogs in the evaluation of RA(BTR) (p = 0.003). Likewise, the IA of the RP(PTR) was the higher the higher the observers´ expertise was with neurologists having significantly highest values (p < 0.001). The RA(PTR) has been evaluated more consistent by practitioners and students than the RA(BTR). For practitioners this difference was significant (< 0.01). Our data suggests that neurologists assess the bicipital and patellar tendon reflex in dogs most reliably. None of the examined risk factors had a significant impact on the degree of IA in the evaluation of RP(PTR), while students had a 4.4-times higher chance of discordance when evaluating the RA(PTR) compared to the other groups. This effect was significant (p < 0.001). Neurologists can reliably assess the bicipital and patellar tendon reflex in healthy dogs. Observer´s level of expertise and the fur length of the dog affect the degree of IA of RA(BTR). The influence of the observer´s expertise is higher on the evaluation of the BTR than on the PTR.

Whether Superficial Abdominal Reflex is Affected by Subcostal Transverse Abdominal Incisions? A Prospective, Observational Early Experience

Introduction:

Superficial abdominal reflex (SAR) is an important part of the neurologic assessment. It is normally present and may be present or absent in various physiological as well as pathological conditions. The presence of an abdominal incision creates a dilemma in the mind of the clinician for it affecting this reflex. As there is no literature on this, we decided to study the effect of abdominal incisions on SAR.

Materials and Methods:

It was a prospective, observational study. We evaluated the patients requiring transverse subcostal incision (range 3–12 cm) both preoperatively and postoperatively, for their abdominal reflexes. Patients with preoperative normal and symmetrical abdominal reflexes were included in the study. Postoperatively, we compared the change of SAR with the preoperative status and analyzed the data.

Results:

A total of 94 patients underwent surgeries, out of which 54 patients came under inclusion criteria, comprising 36 males and 18 females. Subcostal transverse abdominal incisions were made for surgeries including both gastrointestinal and ventriculoperitoneal shunts. SAR was found unaffected by the incisions in all patients.

Conclusions:

Although the study was small, subcostal transverse abdominal incisions were not found to affect SAR.

Experimental investigations of control principles of involuntary movement: a comprehensive review of the Kohnstamm phenomenon

The Kohnstamm phenomenon refers to the observation that if one pushes the arm hard outwards against a fixed surface for about 30 s, and then moves away from the surface and relaxes, an involuntary movement of the arm occurs, accompanied by a feeling of lightness. Central, peripheral and hybrid theories of the Kohnstamm phenomenon have been advanced. Afferent signals may be irrelevant if purely central theories hold. Alternatively, according to peripheral accounts, altered afferent signalling actually drives the involuntary movement. Hybrid theories suggest afferent signals control a centrally-programmed aftercontraction via negative position feedback control or positive force feedback control. The Kohnstamm phenomenon has provided an important scientific method for comparing voluntary with involuntary movement, both with respect to subjective experience, and for investigating whether involuntary movements can be brought under voluntary control. A full review of the literature reveals that a hybrid model best explains the Kohnstamm phenomenon. On this model, a central adaptation interacts with afferent signals at multiple levels of the motor hierarchy. The model assumes that a Kohnstamm generator sends output via the same pathways as voluntary movement, yet the resulting movement feels involuntary due to a lack of an efference copy to cancel against sensory inflow. This organisation suggests the Kohnstamm phenomenon could represent an amplification of neuromotor processes normally involved in automatic postural maintenance. Future work should determine which afferent signals contribute to the Kohnstamm phenomenon, the location of the Kohnstamm generator, and the principle of feedback control operating during the aftercontraction.

Lumbar Thrust Manipulation and Exercise for the Treatment of Mechanical Low Back Pain in Adolescents: A Case Series

Study Design Case series. Background Low back pain (LBP) is an increasing problem in health care. The evidence for the use of spinal manipulative therapy to treat pediatric patients with LBP is minimal. The treatment of pediatrics with manual therapy, particularly spinal manipulation, is controversial within the medical community, primarily with respect to adverse events. The purpose of this case series was to illustrate the feasibility and safety of lumbar manipulation plus exercise in the adolescent population with mechanical LBP. Case Description Three patients-a 13-year-old adolescent girl, 15-year-old adolescent girl, and 13-year-old adolescent boy-were treated in an outpatient physical therapy setting for mechanical LBP. All 3 patients were assessed using a lumbar manipulation clinical prediction rule and treated with sidelying lumbar manipulation and exercise. Outcomes Patients were treated for a total of 10 to 14 visits over a course of 8 to 9 weeks. Pain (measured by a numeric pain-rating scale) and disability (measured by the modified Oswestry Disability Index) improved to 0/10 and 0%, respectively, in each patient. No adverse reactions to manipulation were reported. Discussion The results of this case series describe the use of lumbar thrust manipulation and exercise for the treatment of mechanical LBP in adolescents. The positive results indicate that lumbar manipulation may be a safe adjunct therapy. Further studies, including randomized controlled trials, are needed to determine effectiveness. Level of Evidence Therapy, level 4. J Orthop Sports Phys Ther 2016;46(5):391-398. Epub 6 Apr 2016. doi:10.2519/jospt.2016.6366.

Clinical availability of the deep tendon reflex test using a novel apparatus in healthy subjects

[Purpose] The aim of this study was to investigate the clinical usefulness of a novel apparatus intended to improve the consistency and reliability of the deep tendon reflex (DTR) test. [Subjects] The participants included 50 healthy adults (25 male and 25 female) between 20 and 31 years of age who showed no knee abnormalities upon physical examination. [Methods] The intraclass correlation coefficient (ICC) was used to verify inter-rater reliability for two parameters examined in the DTR test using a newly designed apparatus. These parameters were the patellar reflex amplitude and first knee extension angle. Pearson's product correlation coefficient was then used to examine the correlation between these two parameters. [Results] The inter-rater reliability analysis showed a high correlation between the examiners for both DTR parameters (ICCs = 0.91-0.96). In addition, a significant positive correlation was observed between the two parameters (r = 0.91). [Conclusion] The results show that it is possible to use the novel apparatus described herein to obtain reliable results in the DTR test.

Assessment of hyperactive reflexes in patients with spinal cord injury

Hyperactive reflexes are commonly observed in patients with spinal cord injury (SCI) but there is a lack of convenient and quantitative characterizations. Patellar tendon reflexes were examined in nine SCI patients and ten healthy control subjects by tapping the tendon using a hand-held instrumented hammer at various knee flexion angles, and the tapping force, quadriceps EMG, and knee extension torque were measured to characterize patellar tendon reflexes quantitatively in terms of the tendon reflex gain (G_tr), contraction rate (R_c), and reflex loop time delay (t_d). It was found that there are significant increases in G_tr and R_c and decrease in t_d in patients with spinal cord injury as compared to the controls (P < 0.05). This study presented a convenient and quantitative method to evaluate reflex excitability and muscle contraction dynamics. With proper simplifications, it can potentially be used for quantitative diagnosis and outcome evaluations of hyperreflexia in clinical settings.

The history of examination of reflexes

In the late 1800s, Wilhelm Erb, Joseph Babinski, William Gowers, and others helped develop the neurologic examination as we know it today. Erb was one of the first to emphasize a detailed and systematic neurologic exam and was co-discoverer of the muscle stretch reflex, Gowers began studying the knee jerk shortly after it was described, and Babinski focused on finding reliable signs that could differentiate organic from hysterical paralysis. These physicians and others emphasized the bedside examination of reflexes, which have been an important part of the neurologic examination ever since. This review will focus on the history of the examination of the following muscle stretch and superficial/cutaneous reflexes: knee jerk, jaw jerk, deep abdominal reflexes, superficial abdominal reflexes, plantar reflex/Babinski sign, and palmomental reflex. The history of reflex grading will also be discussed.

Motion analysis of normal patellar tendon reflex

BACKGROUND

Reflex assessment, an essential element in the investigation of the motor system, is currently assessed through qualitative description, which lacks of normal values in the healthy population. This study quantified the amplitude and latency of patellar tendon reflex in normal subjects using motion analysis to determine the factors affecting the reflex amplitude.

METHODS

100 healthy volunteers were recruited for patellar tendon reflex assessments which were recorded using a motion analysis system. Different levels of input strength were exerted during the experiments.

RESULTS

A linear relationship was found between reflex input and reflex amplitude (r = 0.50, P <0.001). The left knee was found to exhibit 26.3% higher reflex amplitude than the right (P <0.001). The Jendrassik manoeuvre significantly increased reflex amplitude by 34.3% (P = 0.001); the effect was especially prominent in subjects with weak reflex response. Reflex latency normality data were established, which showed a gradual reduction with increasing input strength.

CONCLUSION

The quantitative normality data and findings showed that the present method has great potential to objectively quantify deep tendon reflexes.

Analyse du mouvement du réflexe rotulien normal.

Influence of age on patellar tendon reflex response

Background

A clinical parameter commonly used to assess the neurological status of an individual is the tendon reflex response. However, the clinical method of evaluation often leads to subjective conclusions that may differ between examiners. Moreover, attempts to quantify the reflex response, especially in older age groups, have produced inconsistent results. This study aims to examine the influence of age on the magnitude of the patellar tendon reflex response.

Methodology/Principal Findings

This study was conducted using the motion analysis technique with the reflex responses measured in terms of knee angles. Forty healthy subjects were selected and categorized into three different age groups. Patellar reflexes were elicited from both the left and right patellar tendons of each subject at three different tapping angles and using the Jendrassik maneuver. The findings suggested that age has a significant effect on the magnitude of the reflex response. An angle of 45° may be the ideal tapping angle at which the reflex can be elicited to detect age-related differences in reflex response. The reflex responses were also not influenced by gender and were observed to be fairly symmetrical.

Conclusions/Significance

Neurologically normal individuals will experience an age-dependent decline in patellar reflex response.

Lower motor neuron findings after upper motor neuron injury: insights from postoperative supplementary motor area syndrome

Hypertonia and hyperreflexia are classically described responses to upper motor neuron injury. However, acute hypotonia and areflexia with motor deficit are hallmark findings after many central nervous system insults such as acute stroke and spinal shock. Historic theories to explain these contradictory findings have implicated a number of potential mechanisms mostly relying on the loss of descending corticospinal input as the underlying etiology. Unfortunately, these simple descriptions consistently fail to adequately explain the pathophysiology and connectivity leading to acute hyporeflexia and delayed hyperreflexia that result from such insult. This article highlights the common observation of acute hyporeflexia after central nervous system insults and explores the underlying anatomy and physiology. Further, evidence for the underlying connectivity is presented and implicates the dominant role of supraspinal inhibitory influence originating in the supplementary motor area descending through the corticospinal tracts. Unlike traditional explanations, this theory more adequately explains the findings of postoperative supplementary motor area syndrome in which hyporeflexia motor deficit is observed acutely in the face of intact primary motor cortex connections to the spinal cord. Further, the proposed connectivity can be generalized to help explain other insults including stroke, atonic seizures, and spinal shock.

The accuracy of subjective clinical assessments of the patellar reflex

INTRODUCTION

Measurement precision and accuracy of spinal reflexes plays an essential role in the clinical neurological examination. Reflexes are conventionally assessed either electromyographically or with rating scales. In this study we compared objective kinematic T-reflex and subjective assessments of patellar reflexes in 15 normal healthy subjects.

METHODS

Randomized recordings of objectively quantified reflexes were rated by 24 medical students, 16 general practitioners, and 12 neurologists, using a visual analog scale and the NINDS and Mayo clinical reflex scales.

RESULTS

For all groups of raters, Spearman rank correlations showed that subjective ratings significantly correlated with change of knee angle (R2 = 0.72-0.79, P < 0.001) and maximum T-reflex amplitude (R2 = 0.84-0.94, P < 0.001). Stepwise multiple regression analysis showed that all subjective rater groups relied most on the change of knee angle to assess the reflex.

CONCLUSIONS

These findings show that subjective assessments of reflexes using reflex rating scales correlate strongly with biomechanical and electromyographic measures.

The pediatric-modified total neuropathy score: a reliable and valid measure of chemotherapy-induced peripheral neuropathy in children with non-CNS cancers

BACKGROUND

Neurotoxicity is a common side-effect of cancer treatment, but no scales have been validated for the pediatric population. The objective of this study was to test the reliability and validity of the pediatric modified-Total Neuropathy Scale (ped-mTNS) to measure chemotherapy-induced peripheral neuropathy in school-aged children.

METHODS

Forty-one subjects aged 5-18 years undergoing chemotherapy with vincristine or cisplatin and 41 age- and gender-matched controls completed study measures. Subjects were tested with the ped-mTNS at a specified time during treatment. Standardized measures of balance and hand function were completed concurrently. Internal consistency of the ped-mTNS was evaluated using Chronbach's alpha. Validity was tested by comparing case and control ped-mTNS scores as well as testing the hypothesis that ped-mTNS scores would be associated with scores on tests of balance and manual dexterity. Inter-rater and test-retest reliability were each assessed in a subset of 10 subjects.

RESULTS

Twenty-three subjects with acute lymphoblastic leukemia, six with lymphoma, and 12 with solid tumors completed measures along with 41 age- and gender-matched controls. Internal consistency was acceptable with a Chronbach's alpha of 0.76. Children undergoing treatment for cancer had significantly worse scores on the ped-mTNS compared to controls (subjects, 8.7 ± 4.2; controls, 1.4 ± 0.9; p < 0.001). As hypothesized, scores on the ped-mTNS were associated with measures of balance and manual dexterity. Inter-rater and test-retest reliability was acceptable (intraclass correlation coefficients >0.9 each).

CONCLUSIONS

The ped-mTNS is a reliable and valid measure of chemotherapy-induced peripheral neuropathy in school-aged children that is associated with relevant functional limitations.

Reflexes in psychiatry

Psychiatric patients often do not cooperate fully with the neurologic examination. Reflexes virtually bypass patient effort and are difficult to consciously determine. This article reviews muscle stretch (deep tendon) reflexes, and pathological reflexes including the extensor plantar (Babinski) and primitive release reflexes. Topics include findings in common psychiatric and neurologic conditions and methods for eliciting these signs.

The importance of a vibration wave as the trigger for tendon jerks

Proprioceptive tendon reflexes are traditionally regarded as tendon stretch reflexes. Eliciting reflexes with a sharp blow on a tendon is, however, not a physiological stimulus. Based on clinical experience in eliciting these reflexes and neurophysiological investigations it is suggested that vibration is a relevant stimulus for tendon jerks.

Development and testing of a prototype reflex measurement system employing artificial neural networks

This paper presents the development, testing and performance evaluation of a patellar tendon reflex measurement system to provide a quantitative reflex evaluation for use by medical practitioners and in a telemedicine or E-medicine environment. A prototype was developed that makes use of XSens MTx orientation sensors, force-sensitive resistors and an electromyogram to measure the reflex response. Suitable parameters from the sensors were identified for analysis, and clinical testing was performed on 20 subjects to collect data to evaluate the system's performance. Subjective reflex evaluations were conducted by three medical doctors according to a standard reflex grading scale using video recordings of the tests. Multi-layer feed-forward (MLFF) artificial neural networks (ANNs) were used to analyze the collected data with the aim of pattern identification and reflex grading prediction. It was found that the MLFF network delivered the corresponding reflex grading with an accuracy of 85%, which was of the same order as the rate of differences between the subjective reflex evaluations performed by the doctors (80%). The use of ANNs to analyze a reflex measurement offers a repeatable and concise representation of the reflex that is familiar to doctors and can be developed for use in a general clinical setting or for telemedicine purposes.

Segmental abdominal wall paresis caused by lateral low thoracic disc herniation

STUDY DESIGN

Clinical, radiologic, and neurophysiologic description of 2 cases.

OBJECTIVE

To describe 2 cases with spontaneous deep unilateral abdominal pain as the first symptom of thoracic disc herniation at a low thoracic vertebral level, further manifested by unilateral partial paresis of the obliquus abdominis muscle.

SUMMARY OF BACKGROUND DATA

Clinical manifestation of lateral thoracic disc herniation with electrophysiologic results and conservative therapy as treatment of choice when spinal cord functions are preserved.

METHODS

Magnetic resonance imaging revealed bilateral paramedian disc protrusions at T12-L1 in Patient 1 and foraminal herniation at T10-T11 and paramedian herniation at T11-T12 in Patient 2. Electromyography (EMG) and evoked potentials were investigated in the acute stage and after 6 months.

RESULTS

Spontaneous activity on needle EMG confirmed axonal root impairment. Somatosensory and motor-evoked potentials were within normal limits and excluded spinal cord involvement. Nonsteroidal anti-inflammatory drugs and periradicular injection of steroids and local anesthetics rendered both patients pain-free. Normalization of muscle strength within 3 to 6 months was accompanied by EMG findings of reinnervation.

CONCLUSION

Lateral disc herniation causing compression of a thoracic root associated with unilateral segmental paresis of the abdominal wall is a rare condition. Despite EMG documentation of axonal root lesion, however, a purely conservative therapeutic approach may be considered treatment of choice in cases without spinal cord involvement.

Reflexes in prior polio and their relation to weakness and anterior horn cell loss

The aim of this study was to evaluate the reflex pattern in patients with prior polio and to relate these findings to the degree of anterior horn cell (AHC) involvement and loss of muscle force. Twenty-five prior polio subjects were investigated with electromyography (EMG), force testing and reflex studies, which included the patellar and Achilles reflex, H-reflex, T-response and interlimb reflex (ILR). The clinical reflexes, H/M-ratio and T-response amplitude at rest were positively correlated with force and negatively correlated with the degree of AHC loss. The H/M-ratio was decreased compared with age matched controls. ILR was present in 68% of the prior polio patients but did not exist in controls. The presence of the ILR was not correlated with the degree of AHC loss or force. The reflex studies gave two main findings. The first is reduced excitability of monosynaptic connections in the motor neuron pool, which is related to weakness. The other is the presence of ILR as an indicator of interneuronal hyper-excitability, which is not related to weakness.