New observations on neuronal organization of reflexes from tendon organ afferents and their relation to reflexes evoked from muscle spindle afferents.
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Animals↗
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Determinants of prognosis of acute transverse myelitis in children.
BACKGROUND: Acute transverse myelitis (ATM) is a severe disorder; recovery requires several months and often leaves neurologic residua. To determine what features of patients with acute transverse myelitis significantly influence prognosis, the authors reviewed reports of ATM in Japanese children published in the last 15 years (from 1987 to 2001). METHODS: The authors studied reports of 50 Japanese patients (17 boys, 26 girls, 7 children of unspecified sex; mean age +/- SD, 8.0 +/- 3.8 years). Acute-phase and demographic features including age, increased deep tendon reflexes, Babinski reflex, sex, preceding infection, decreased deep tendon reflexes, time course of peak neurologic impairment, treatment with prednisolone and/or high-dose methylprednisolone, and the day of illness when treatment was started were used as independent variables in a regression analysis. The dependent variable was long-term persistence of neurologic deficits. RESULTS: Younger patients and those without increased deep tendon reflexes or a Babinski reflex were more likely to have residual neurologic deficits such as paraplegia or tetraplegia, sensory loss and sphincter disturbance. No relationship was seen between prognosis and sex, preceding infections, decreased deep tendon reflexes, time course of peak neurologic impairment, treatment with prednisolone or high-dose methylprednisolone, or timing of treatment initiation. CONCLUSIONS: Age at onset and neurologic features were important for outcome prediction in ATM. Steroid therapy did not associate with better outcome.
Adolescent↗
Conditioned patellar tendon-tap reflexes in patients with ACL reconstruction.
The patellar tendon-tap stretch reflexes were examined in six neurologically healthy young subjects (mean age = 27.1 yrs) who had developed persistent quadriceps strength deficit due to ACL reconstruction. Each subject was tested on two separate days. A specially designed apparatus was used to examine the unilateral and conditioned patellar tendon-tap reflex response utilizing three different conditioning intervals: 25 ms, 75 ms, 150 ms, and a unilateral reflex (control). Peak isometric force and contraction time were measured by using a strain gauge. Also, peak-to-peak EMG was measured by using bipolar surface electrodes which were placed over the middle of the rectus femoris. All data were collected with a microcomputer (sample rate = 1 kHz). Due to the small sample, the Kruskal-Wallis nonparametric analysis of variance was performed. All subjects demonstrated quadriceps strength deficits in the ACL leg when compared with the contralateral leg. This analysis determined that for both the ACL leg and the Non ACL leg the size of stretch reflex was facilitated at the long-latency conditioning intervals (75 and 150 ms), whereas it was inhibited at the short-latency conditioning interval (25ms). However, the ANOVA model failed to reveal any differences in the conditioned stretch reflex between the ACL leg and the Non ACL leg. Also, no differences were observed at the unilateral condition. Taken together, these results indicate that ACL reconstruction results in significant strength deficits, but does not alter unilateral or conditioned reflex profiles.
Adult↗
Effect of static stretch training on neural and mechanical properties of the human plantar-flexor muscles.
To determine the contributions of neural and mechanical mechanisms to the limits in the range of motion (ROM) about a joint, we studied the effects of 30 sessions of static stretch training on the characteristics of the plantar-flexor muscles in 12 subjects. Changes in the maximal ankle dorsiflexion and the torque produced during passive stretching at various ankle angles, as well as maximal voluntary contraction (MVC) and electrically induced contractions, were recorded after 10, 20, and 30 sessions, and 1 month after the end of the training program. Reflex activities were tested by recording the Hoffmann reflex (H reflex) and tendon reflex (T reflex) in the soleus muscle. Training caused a 30.8% (P < 0.01) increase in the maximal ankle dorsiflexion. This improved flexibility was associated (r(2) = 0.88; P < 0.001) with a decrease in muscle passive stiffness and, after the first 10 sessions only, with a small increase in passive torque at maximal dorsiflexion. Furthermore, both the H- and T-reflex amplitudes were reduced after training, especially the latter (-36% vs. -14%; P < 0.05). The MVC torque and the maximal rate of torque development were not affected by training. Although the changes in flexibility and passive stiffness were partially maintained 1 month after the end of the training program, reflex activities had already returned to control levels. It is concluded that the increased flexibility results mainly from reduced passive stiffness of the muscle-tendon unit and tonic reflex activity. The underlying neural and mechanical adaptation mechanisms, however, showed different time courses.
Adult↗
Biceps femoris tendon jerk reflexes are enhanced at the end of the swing phase in humans.
The phase-dependent modulation of the biceps femoris (BF) tendon jerk reflexes was investigated in a reduced form of walking. All subjects (12) investigated showed tendon reflexes throughout the whole step cycle but the amplitude was largest in the middle and late swing phase of the ipsilateral leg. It is concluded that the normally occurring BF burst at end swing could be due to stretch-induced activity.
Electromyography↗
Symptoms of thoracolumbar junction disc herniation.
STUDY DESIGN: A retrospective clinical review of patients with thoracolumbar junction disc herniation. OBJECTIVES: To evaluate the clinical features of thoracolumbar junction disc herniation and to prepare a chart for the level diagnosis in the neurologic findings and symptoms. SUMMARY OF BACKGROUND DATA: Thoracolumbar junction disc herniations show a variety of signs and symptoms because of the complexity of the upper and lower neurons of the spinal cord, cauda equina, and nerve roots. Furthermore, much is still unknown about thoracolumbar junction disc herniations because of their rare frequency. METHODS: The clinical features of 26 patients who had undergone operations for single disc herniations at T10-T11 through L2-L3 were investigated. Affected levels were as follows: 2 patients with disc herniation at T10-T11 disc, 4 patients at T11-T12, 3 patients at T12-L1, 6 patients at L1-L2, and 11 patients at L2-L3. The level of disc space of interest was confirmed with whole-spine plain roentgenograms. The caudal end of the cord was judged by magnetic resonance imaging and computed tomographic myelogram. RESULTS: Two patients with T10-T11 disc herniation showed moderate lower extremity weakness, increased patellar tendon reflex, and sensory disturbance of the entire lower extremities. Three of four patients with T11-T12 disc herniation experienced lower extremity weakness, and three patients had accentuated patellar tendon reflex. Sensory disturbance was observed in the anterolateral aspect of the thigh in one patient and on the entire leg in three patients. Bowel and bladder dysfunction was noted in three patients. In the T12-L1 disc herniation group (n = 3), muscle weakness and atrophy below the leg were advanced, and bowel and bladder dysfunction were also noted. Two of these three patients had bilateral drop foot, and one patient had unilateral drop foot; sensory disturbance was noted in the sole or foot and around the circumference of the anus, and the patellar tendon reflex and Achilles tendon reflex were absent. All six patients with L1-L2 disc herniation showed severe thigh pain and sensory disturbance at the anterior aspect or lateral aspect of the thigh. On the other hand, there were no clear signs of lower extremity weakness, muscle atrophy, deep tendon reflex, or bowel and bladder dysfunction in these patients. In the L2-L3 disc herniation group (n = 11), all patients had severe thigh pain and sensory disturbance of the anterior aspect or the lateral aspect of the thigh. Weakness in the quadriceps was noted in five patients and weakness in the tibialis anterior in two patients. Decreased or absence of patellar tendon reflex was observed in nine patients. Five patients had positive straight leg raising test results, and eight patients showed positive femoral nerve stretch test results. CONCLUSION: Among thoracolumbar junction disc herniations, T10-T11 and T11-T12 disc herniations were considered upper neuron disorders, T12-L1 disc herniations were considered lower neuron disorders, L1-L2 disc herniations were considered mild disorders of the cauda equina and radiculopathy, and L2-L3 disc herniations were considered radiculopathy. These findings had relatively distinct differences among herniated disc levels.
Adult↗
[A new tendon stretch reflex; its significance in disease of the pyramidal tract].
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Disease↗
Exercise-induced neuromuscular dysfunction under reflex conditions.
The purpose of this research was to describe further the effects of exercise-induced muscle damage on reflex sensitivity. The subjects were eight physically active, but untrained males, between the ages of 18 and 29 years. The effects of eccentric and concentric exercise on patellar tendon reflex responses were determined. The 8 week experiment consisted of two, 5 day, test protocols with a 6 week wash-out period between test protocols. Each 5 day test protocol consisted of the following six test sessions: (1) day 1--baseline, (2) day 2 baseline, (3) day 2--immediate post-exercise, and (4-6) days 3-5: 24, 48, and 72 h post-exercise. On day 2, the subjects made either 100 fatiguing concentric or eccentric isotonic contractions using the right leg at 75% of the corresponding repetition maximum values. During each test session, the electromyogram (EMG) and force-time characteristics of basic and conditioned patellar tendon reflex responses were measured. The reflex amplitudes of basic and conditioned patellar tendon reflex responses were decreased following fatiguing concentric exercise. There were no immediate effects of fatiguing eccentric exercise on the basic and conditioned patellar tendon reflex responses, but the EMG amplitudes of these reflex responses were reduced on the days following eccentric exercise. The amount of conditioned patellar tendon reflex facilitation was decreased following the concentric exercise protocol and at 48 h post-eccentric exercise. Our conditioned reflex data suggest that post-exercise changes to the physiological mechanisms that modulate the recruitment gain of the alpha-motoneuron pool may depend upon the type of fatiguing exercise.
Adolescent↗
Distinct phenotypes within autosomal recessive ataxias not linked to already known loci.
Autosomal recessive ataxias represent a large group of neurodegenerative disorders characterized by progressive degeneration of central and peripheral nervous systems and a genetic heterogeneity. To analyse clinical, neurophysiological and nerve biopsy findings in 14 Tunisian unrelated families showing linkage exclusion to the known autosomal recessive ataxia loci, 20 Tunisian families with a total of 73 affected subjects were selected on the presence of a clinical phenotype associating a cerebellar ataxia with retained tendon reflexes on at least the index patient. A genetic linkage study was performed with markers spanning the Friedreich ataxia, Spastic ataxia of the Charlevoix-Saguenay, Autosomal recessive ataxia associated with isolated vitamin E deficiency, Ataxia with oculomotor apraxia, Infantile onset spinocerebellar ataxia, Ataxia with Hearing Loss and Optic Atrophy, AT, ATLD, Spinocerebellar ataxia with axonal neuropathy, Cayman ataxia, Cerebellar ataxia with mental retardation optic atrophy and skin abnormalities, Salla syndrome, Marinesco-Sjögren and the Childhood Spinocerebellar Ataxia loci. Out of the 20 families, 4 showed linkage to the spastic ataxia of the Charlevoix-Saguenay locus, one to the Friedreich ataxia locus and one to the Ataxia with oculomotor apraxia locus. Linkage to all tested loci has been excluded in the 14 remaining families. These families were divided into 3 groups according to tendon reflex status in lower limbs which appear as the most obvious distinguishing clinical sign between patients and families: Group A was characterized by brisk tendon reflexes in lower limbs, group B by a homogeneous feature of tendon reflexes with the absence of ankle reflexes and brisk knee reflexes and group C by variable features of tendon reflexes in lower limbs within the same family. Haplotype analysis and Lod score calculation did not show any evidence of linkage to the 16 known loci of cerebellar ataxias. Aim of this study was to reveal the vast clinical phenotypic variability in patients with autosomal recessive ataxia not linked to known loci. Data obtained indicate that detailed clinical and neurophysiological nerve investigations will be essential in order to pool patients within homogeneous subgroups for gene mapping.
Cerebellar Ataxia↗
Locus heterogeneity in Friedreich ataxia.
Friedreich ataxia (FRDA) is the most common form of autosomal recessive ataxia. The disease locus was assigned to chromosome 9 and the disease gene, STM7/X25, has been isolated. To date most data suggest locus homogeneity in FRDA. We now provide strong evidence of a second FRDA locus. Studying two siblings with FRDA from two families we did not detect a mutation in STM7/X25. Haplotype analysis of the STM7/X25 region of chromosome 9 demonstrated that the relevant portion of chromosome 9 differs in the patients. Although the patients studied had typical FRDA, one sibpair had the uncommon symptom of retained tendon reflexes. In order to investigate whether retained tendon reflexes are characteristic of FRDA caused by the second locus, FRDA2, we studied an unrelated FRDA patient with retained tendon reflexes. The observation of typical mutations in STM7/X25 (GAA expansions) in this patient demonstrates that the two genetically different forms of FRDA cannot be distinguished clinically.
Adaptor Proteins, Signal Transducing↗
[Adie's syndrome].
The author has investigated patients suffering from disorders of the pupillary reflexes and of the tendon reflexes of the lower limbs which come under the heading of tonic pupil. Forty-five patients were followed up over a period of 15 years. The tendon reflexes of the lower limbs were recorded graphically and showed a very characteristic retardation of the second phase of the patellar reflex. The aetiopathogenesis of Adie's syndrome is discussed. The pathogenesis of Adie's syndrome has so far not been definitely established. We have merely tried to point out a few of the features which permit its early diagnosis and have drawn attention to the basic problem of the pathogenesis of certain neuro-muscular disorders on the basis of secondary considerations involved in this uncommon syndrome.
Adie Syndrome↗
[Polyneuropathies from solvents].
Polyneuropathy is a clinically diagnosed disorder. The diagnostic features consist mainly of subjective complaints about distally marked paresthesia or dysaesthesia, pain and motor disturbances like cramps. Neurological examination typically shows weak or absent tendon reflexes (early signs: weak or absent Achilles tendon reflexes), distally marked disturbances of sensitivity (early sign: reduced sense of vibration), atrophic paresis, cranial nerve impairment and disturbances of the autonomic nervous system. Results of additionally performed electrophysiological examinations (nerve conduction studies, vibratometry and thermotesting) contribute to the diagnosis. Polyneuropathy is undoubtedly induced by carbon disulfite, ethylene glycol, n-hexane and methyl-n-butylketone, triorthocresyl phosphate and solvent mixtures. Induction of polyneuropathy is doubtful with the following substances: tetrachloride, trichlorethylene, styrene, toluene. Additional impairment of the central nervous system is often indicated by clinical findings of brisk patellar tendon reflexes or the occurrence of Babinski's sign.
Humans↗
Novel C59T leader peptide mutation in the MPZ gene associated with late-onset, axonal, sensorimotor polyneuropathy.
The objective of this study was to report a novel exon-1 mutation in the myelin protein zero (MPZ) gene, resulting in axonal Charcot-Marie-Tooth neuropathy with recurrent hyper-CK-emia. In a 64-year-old woman slowly progressive distal lower limb weakness, muscle cramps in the lower limb muscles, and stocking-type numbness had developed from the age of 61. Neurologic examination revealed discrete hip flexor weakness, weakness for foot extension, diffuse wasting of the distal lower limb muscles, reduced patella tendon reflexes, and absent Achilles tendon reflexes. There was recurrently elevated creatine kinase with a maximum of 607 U/l (n, <145 U/l). Stimulation of the peroneal and tibial nerves did not evoke a muscular response. Electromyography was neurogenic. Biopsy of the right sural nerve showed diffuse axonal degeneration and loss of axons of all diameters. Muscle biopsy showed increased fiber-size variability, angulated fibers, internalized nuclei, accumulations of nuclei, grouped atrophic muscle fibers, and fiber splitting. Molecular genetic analysis by PCR and direct nucleotide sequencing revealed the heterozygous C59T exon-1 MPZ gene mutation, resulting in the amino acid exchange S20F of the MPZ signal protein domain (leader peptide). The novel C59T mutation in the leader peptide of the MPZ gene is pathogenic and manifests as severe, late-onset, axonal, symmetric sensorimotor polyneuropathy (CMT2) and hyper-CK-emia.
Charcot-Marie-Tooth Disease↗
Limiting mechanisms of force production after repetitive dynamic contractions in human triceps surae.
The influence of repetitive dynamic fatiguing contractions on the neuromuscular characteristics of the human triceps surae was investigated in 10 subjects. The load was 50% of the torque produced during a maximal voluntary contraction, and the exercise ended when the ankle range of motion declined to 50% of control. The maximal torque of the triceps surae and the electromyographic (EMG) activities of the soleus and medial gastrocnemius were studied in response to voluntary and electrically induced contractions before and after the fatiguing task and after 5 min of recovery. Reflex activities were also tested by recording the Hoffmann reflex (H reflex) and tendon reflex (T reflex) in the soleus muscle. The results indicated that whereas the maximal voluntary contraction torque, tested in isometric conditions, was reduced to a greater extent (P < 0.05) at 20 degrees of plantar flexion (-33%) compared with the neutral position (-23%) of the ankle joint, the EMG activity of both muscles was not significantly reduced after fatigue. Muscle activation, tested by the interpolated-twitch method or the ratio of the voluntary EMG to the amplitude of the muscle action potential (M-wave), as well as the neuromuscular transmission and sarcolemmal excitation, tested by the M-wave amplitude, did not change significantly after the fatiguing exercise. Although the H and T reflexes declined slightly (10-13%; P < 0.05) after fatigue, these adjustments did not appear to have a direct deleterious effect on muscle activation. In contrast, alterations in the mechanical twitch time course and postactivation potentiation indicated that intracellular Ca(2+)-controlled excitation-contraction coupling processes most likely played a major role in the force decrease after dynamic fatiguing contractions performed for short duration.
Adult↗
Blood thiamine levels in outpatients with diabetes mellitus.
In 46 diabetic outpatients consisting of 20 males and 26 females not given thiamine treatment, the blood thiamine level was 46.9 +/- 28.5 ng/ml (mean +/- SD) and only 23.9% of all cases had a value of more than the normal lower limit (50 ng/ml). Erythrocyte transketolase activity was 443.8 +/- 107.7 micrograms/ml/h and only 20.9% had a value of ore than the normal lower limit (50 micrograms/ml/h), and the erythrocyte TPP effect was 16.6 +/- 13.2%. Moreover, there was a significant positive correlation (r = 0.97) between the blood thiamine level and erythrocyte transketolase activity, and a significant inverse correlation (r = -0.525, r = -0.576) between blood thiamine level and/or erythrocyte transketolase activity and the erythrocyte TPP effect. In 24 diabetic outpatients consisting of 14 males and 10 females given thiamine treatment, the blood thiamine level was 96.5 +/- 44.5 ng/ml/h excluding one case (621.7 ng/ml), and it was higher than the normal lower limit in 83% of all cases. Erythrocyte transketolase activity was 513.9 +/- 133.4 micrograms/ml/h and it was higher than the normal lower limit in 58.3%. Erythrocyte TPP effect was 5.84 +/- 8.39%. There was also a significant positive correlation (r = 0.663) between blood thiamine level and erythrocyte transketolase activity, and a significant inverse correlation (r = 0.0668, r = 0.834) between blood thiamine level and/or erythrocyte transketolase activity and erythrocyte TPP effect. Blood thiamine level and erythrocyte transketolase activity were significantly higher in diabetic outpatients given thiamine treatment than in diabetic outpatients not given thiamine treatment, while the erythrocyte TPP effect was significantly lower in diabetic outpatients given thiamine treatment than in diabetic outpatients not given thiamine treatment. There was no direct relationship between the lowered response of patellar tendon reflex and the biochemical status of thiamine. From the above findings it was concluded that diabetic outpatients tend to have a low blood thiamine level, with low erythrocyte transketolase activity and high erythrocyte TPP effect, and showed marginal thiamine deficiency.
Adult↗
Proceedings: Tendon organs and tendon organ reflexes in decapod crustacea.
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Action Potentials↗
[Characteristic neurological signs in patients with cervical disc disease].
In cervical radiculopathy, neurological findings for the upper extremities and the responsible level of the radices have been precisely detailed. However, in cases of cervical spondylotic myelopathy, it is not always easy to determine the responsible level of the cervical spine solely based on neurological findings. To disclose characteristic neurological lesions of the upper extremities, if any, for different locations of disc disease, 49 patients with cervical disc protrusion at single levels, confirmed by magnetic resonance imaging, were analyzed. Thirty-six patients demonstrated long tract signs (LTS) concomitant with segmental signs in the upper extremities, and 13 patients had no LTS. Except for deep tendon reflexes and the extent of dysesthesia in the upper extremities, there were no characteristic neurological findings, such as muscle atrophy, loss of muscle strength, extent of hypalgesia, or hypesthesia, pointing to the responsible compression site. In the 13 patients without LTS, the extent of dysesthesia and diminution of deep tendon reflexes proved to be completely in agreement with results for radiculopathy: 9 had protruded discs at the C56 level and described dysesthesia in the thumb and the index finger with deep tendon reflexes in the biceps and brachioradialis being diminished. The remaining 4 had protruded discs at the C67 level and described dysesthesia in the middle finger. Their deep tendon reflexes in the triceps were diminished. A clear contrast was observed for the patients with LTS. Four out of 36 patients had C34 protruded discs and did not complain of dysesthesia in any digits. Their deep tendon reflexes were exaggerated in all muscles in the upper extremities.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
[Tendon areflexia in congenital myopathies accompanied by atrophy of type I fibers. Electrophysiologic study].
A predominance and/or an atrophy of type I fibers and a loss of deep tendon reflexes are often observed in different types of congenital myopathy. Various data indicate that both findings can be linked: dysfunction of the myotatic reflex can induce predominant involvement of type I fibers. In order to specify the mechanism of the loss of tendon reflex, an investigation of the Hoffmann reflex (H reflex) was performed in one case of centronuclear myopathy and in one case of congenital type fiber disproportion with type I hypertrophy. The Achilles tendon reflex was absent but the H reflex showed normal recruitment amplitude and latency. The Jendrassik maneuver reinforced the H reflex. These results indicate the involvement of muscle spindles or impairment of the fusimotor system. Nuclear bag intrafusal fibers have common characteristics with type I extrafusal fibers. Both types of fibers could be involved simultaneously in congenital myopathies, thus explaining the loss of tendon reflex.
Child↗