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PubMed1973

Achilles tendon reflex in accidental hypothermia and hypothermic myxoedema.

The photomotogram (P.M.G.) of the Achilles tendon reflex was studied in 26 patients with hypothermia (rectal temperature 33.3 degrees C or less), 10 of whom also had myxoedema (serum protein bound iodine 2.8 mug/100 ml or less). No reflex could be elicited in eight (31%) of these patients, including three of those with myxoedema. Hypothermia increases both the contraction and the relaxation times of the reflex, the relaxation phase being particularly prolonged in those with myxoedema. In those patients from whom the reflex was elicited the ratio of the contraction time to the "half-relaxation time" in the P.M.G. was less than unity in six of the seven with myxoedema, and considerably greater than unity in eight of the 11 (73%) who were euthyroid. Thus, analysis of the Achilles tendon reflex P.M.G. correctly predicted the thyroid status in 14 of the 18 hypothermic patients in whom the Achilles tendon reflex was present (78%). The wider use of this rapid test of thyroid function would allow a more rational use of thyroid hormones in hypothermic patients and so lead to a better assessment of their value.

Achilles Tendon↗
PubMed1999

[Physical diagnostics--tendon reflexes].

Clinical examination of the tendon reflexes is helpful in localising lesions in the nervous system, which is an important step in the diagnosis of neurological disorders. The large intra- and interindividual variations of reflex amplitudes make interpretation difficult. Published interobserver agreement studies provide conflicting results. The diagnostic specificity of unequivocally abnormal reflexes is moderate to good (70-95%, decreasing with increasing age), but the sensitivity is lower (50-70%), both for peripheral and for central lesions. This implies that the finding of a clearly abnormal reflex pattern is often helpful, but the finding of normal reflexes usually does not exclude a neurological lesion.

Brain Diseases↗
PubMed1994

Tendon-reflex testing in chronic demyelinating polyneuropathy.

We studied the tendon reflex (T-reflex) in 26 patients with acquired chronic demyelinating polyneuropathy (CDN), including 22 with chronic inflammatory demyelinating polyneuropathy (CIDP). In 7 patients reflexes were brisk or normal on clinical testing. The height adjusted T-reflex was abnormal in 25 (96%) cases, including 6 of 7 patients with brisk or normal reflexes on clinical testing. Mean latency (P < 0.01) and duration (P < 0.05) of the ankle and patellar tendon reflexes were significantly prolonged in the CIDP patients when compared to the controls. Mean latency in the CIDP patients was 152% of normal means. In 7 CIDP patients, the T-reflex latencies were prolonged beyond 150% of normal means. Thus, the T-reflex test is abnormal in a majority of patients with CDN, even in the presence of well-preserved clinical reflexes, and the T-reflex latency is a useful indicator of the presence of a demyelinating peripheral neuropathy in some patients.

Adult↗
PubMed1997

Normal values of patellar and ankle tendon reflex latencies.

The clinical value of latency measurement of tendon reflexes in neurological patients has been reported by several authors. However, normal values are not readily comparable. In the present study, latencies and amplitudes of patellar (PTR) and ankle tendon reflexes (ATR) were measured at rest and after facilitation in 102 normal controls. A manually operated reflex hammer, tipped with electrically conductive rubber, ensured an immediate start of the sweep of the oscilloscope. Latencies showed a significant correlation with height (r = 0.70 for PTR and r = 0.72 for ATR, P < 0.0001) and to a lesser degree with age (r = 0.16 and r = 0.30, P < 0.0001). While amplitudes were highly variable, rendering them less useful for diagnostic purposes, latencies showed minimal intra-individual variability (CV 1.5 and 0.8%, respectively). Correlation of ATR-latency with the H-reflex latency of the soleus muscle was very high (r = 0.97, P < 0.0001). Comparison with three other hammer types yielded corresponding results with a hammer supplied with a piezo-electric element; however, significantly shorter latencies were found with a hammer with a microswitch, and with another hammer with a spring-contact, due to a delay from the tap on the tendon until the start of the sweep of the monitor.

Adult↗
PubMedDate not supplied

The tendon reflexes in the electrodiagnosis of sciatica.

In order to determine the diagnostic value of the electromyographically tested tendon reflexes (ETR) in lumbosacral radiculopathies, we compared the latency and amplitude of the knee (EKTR) and Achilles tendon reflex (EATR) to their clinical testing and to the EMG and H reflex values in 200 non selected patients (126 men, 74 women) aged 24-68 years (48.6 +/- 9.4). The control group was composed of 50 healthy volunteers (28 men, 22 women) aged 25-60 yrs (44 +/- 8.5). The combined electrophysiological reflex examination was abnormal in 45% of the affected limbs, being the most frequent pathological finding. EMG was abnormal in 34.4% and H reflex in 30.4% of the affected limbs. Furthermore, the EATR taken separately was more sensitive than the H-reflex (42.8% versus 30.4%). Pathological ETR were elicited in a considerable percentage of the clinically normal tendon reflexes (TR): 7.3% of the knee and 14.1% of the Achilles TR. On the other hand 65% of the clinically absent ATR were recorded electrically producing abnormally low and delayed muscle evoked potentials.

Adult↗
PubMedDate not supplied

Deep tendon reflexes: the what, why, where, and how of tapping.

Deep tendon reflexes demonstrate the homeostasis between the cerebral cortex and the spinal cord. When these reflexes are disrupted, hyperreflexia (disease induced) or hyporeflexia/areflexia (drug induced) occurs. Although nurses perform deep tendon reflex assessments regularly, it is difficult to incorporate theoretical principles in these assessments because of scant medical literature, a lack of nursing research, and time constraints in nursing programs. These conditions usually result in one-on-one training, causing reduced consistency. A comprehensive examination assists the clinician to apply theoretical principles, develop expert technique, and serve as a catalyst for clinical research.

Humans↗
PubMed1978

Relationship of the patellar tendon reflex to the ventral branch of the fifth lumbar spinal nerve in the dog.

The lumbosacral plexuses of dogs were exposed, using a ventral abdominal approach. In 4 dogs, the ventral branches (VB) of the 4th, 5th, 6th, or 7th lumbar spinal nerves were severed bilaterally. In 4 other dogs, the VB of combinations of 3 of these lumbar spinal nerves were severed so that the branch of only 1 nerve was kept intact. Among many neurologic deficits seen, the reflex of the patellar tendon was absent if the VB of the 5th lumbar spinal nerve was severed and was present if the branch was left intact. This finding was confirmed in another 12 dogs in which the VG of the 5th lumbar spinal nerve was severed on 1 side and the VB of the 4th and 6th lumbar spinal nerves were severed on the opposite side. In 4 additional dogs, the dorsal and ventral roots of the 5th lumbar spinal cord segment were isolated by dorsal laminectomy. Severing the dorsal root caused loss of the patellar tendon reflex, whereas severing the ventral root resulted in hyporeflexia. These findings would suggest that the major afferent impulse elicited by tapping the patellar tendon reaches the spinal cord by way of the dorsal root of the 5th lumbar spinal nerve.

Animals↗
PubMed1989

Measurement of tendon reflexes by surface electromyography in normal subjects.

A simple method for measuring the tendon reflexes was developed. A manually operated, electronic reflex hammer was applied that enabled measurement of the strength of tendon taps. Reflex responses were recorded by surface electromyography. Stimulus-response relations and latencies of tendon reflexes in the biceps, triceps, quadriceps and triceps surae were examined in 40 healthy subjects. A characteristic relation between stimulus strength and response amplitude was found which could be described by an empirical function. Latencies of both arm and leg reflexes were linearly related to the height of the subjects. Variations of reflex amplitudes within and between subjects were comparable with previous results obtained with more complicated techniques. Although repeatability of measurement of the amplitude is limited by the variability of reflexes, significant agreement was found between repeated measurements. Most reflex amplitudes were diminished during repeated examination after a short interval. Both measurement and clinical examination showed the frequent occurrence of left-right asymmetry of reflex amplitudes. These left-right differences were reproducible to a significant degree on repeated measurements after more than 2 years.

Adult↗
PubMedDate not supplied

[Soleus muscle reflexes evoked by stimulation of the posterior tibial nerve compared to tendon reflexes in man (author's transl)].

The characteristics of the reflex response evoked in the soleus muscle after stimulation of the posterior tibial nerve at the ankle were contrasted with the achilleus tendon reflex in 14 healthy volunteers and in a group of selected neurological patients. The following features were examined: conditions of stimulation including stimulation frequency; appearance of reflex activity in muscles other than soleus, effect of the vibratory stimulation, interactions with voluntary contraction. Moreover, a reflex response is described in the soleus following stimulation of the sural nerve. The results have shown a marked jitter in latencies of the responses, a pattern of coactivation of antagonistic muscles, a clear increase of amplitude under vibration or voluntary contraction, normal responses both in spasticity and in S1 radiculopathy with achilleus areflexia. All these data differ from those observed with the tendon jerk of the same amplitude and differentiate the two responses. It is concluded that the reflex evoked by stimulation of the tibial nerve at the ankle is a polysynaptic response of cutaneous origin.

Achilles Tendon↗
PubMed1975

Effects of fatiguing isometric exercise upon achilles tendon reflex and plantar flexion reaction time components in man.

Effects of three different fatiguing local muscular exercises upon plantar flexion reaction time and achilles tendon reflex time have been studied in 24 normal males. The Exercise Conditions, each involving a series of 30 maximal voluntary isometric contractions (MVC) of the plantar flexors, differed by allowing either 5, 10 or 20 sec rest interval between each MVC. Decrements in strength ranged from 15% to 34% MVC. Trend analysis of the fatigue patterns revealed that a cubic orthogonal polynomial equation was sufficient to describe the profile of MVC decrement for all conditions. Following the fatiguing exercise, simple visual reaction time (plantar flexion), and its two components, premotor and motor time, failed to demonstrate any change from Pre Exercise Conditions. Achilles Tendon Reflex Times, however, demonstrated a marked augmentation, as manifest in reduced total reflex times, contraction times and half relaxation times. These results may suggest the differential fatigue of motor units employed in the three motor tasks, viz. MVC, voluntary reaction and achilles tendon reflex. A plausible explanation for the augmentation of the reflex contraction resides in the known potentiating effect of elevated intramuscular temperature. Alternatively, one might postulate a neurally mediated increase in gain of the stretch servomechanism. The possibility of both mechanisms being operative is not excluded.

Achilles Tendon↗
PubMedDate not supplied

Measurement of patellar and ankle tendon reflexes in normal subjects.

In order to acquire normal values, patellar and ankle tendon reflexes were measured bilateral in 51 healthy subjects. The reflexes were mechanically evoked with a hand-held hammer which was connected to the trigger input of a two-channel EMG system. For each reflex simultaneous registration took place from surface electrodes on two different locations. The dependence of the latency on body length and age is described as well as the left-right difference and the intra-individual variability. Using similar measurement conditions significantly longer latencies were found than those published earlier. The importance of well defined placement of the electrodes when comparing acquired latencies with normal values is shown.

Adult↗
PubMed1996

Age-dependent effects of muscle vibration and the Jendrassik maneuver on the patellar tendon reflex response.

OBJECTIVE: To explore possible effects of aging on the excitability of spinal reflexes. DESIGN: Using a cross-sectional design, the influences of muscle vibration and the Jendrassik maneuver on patellar tendon reflex function were compared between 30 young adults and 15 older adults. SETTING: Motor control research laboratory. SUBJECTS: The young adults were volunteers of college age. The older adults (74.5 +/- 4.14 yr) were volunteers from the local community. All subjects were free of medications and neurological conditions that would affect normal neuromuscular responses. MAIN OUTCOME MEASURES: A force-time curve analysis of the patellar tendon reflex response was used to assess the inhibition and facilitation of spinal reflexes. In the experimental protocol to assess spinal reflex inhibition, 100 Hz vibration was applied to the right quadriceps muscle. In another experimental protocol, spinal reflex facilitation was assessed using the Jendrassik maneuver. To perform the Jendrassik maneuver, subjects were instructed to grasp their hands together and to pull as hard as possible while breathing normally. After a 2-second count, the tendon tap was delivered to the right leg and the subject was instructed to relax. In both experimental protocols, control patellar tendon reflexes were collected. RESULTS: Analysis of variance for reflex peak force revealed a significant 30% reduction in the amount of vibration-induced reflex inhibition with increasing age, and a similar 33% reduction in the amount of Jendrassik maneuver facilitation observed for the older adults as compared with the younger adults. CONCLUSION: These results support the hypothesis that inhibitory and excitatory influences acting on the alpha motoneuron pool are different in young and older adults.

Adult↗
PubMed2004

The effect of elbow position on biceps tendon reflex.

BACKGROUND: Testing of tendon (T) reflex is the basic method used in the diagnostic procedure of clinical neurology. Measurement of T reflexes precisely can be a valuable adjunct to clinical examination. Quantification of T reflexes may provide more accurate results. AIMS: To analyze the effect of elbow position on biceps T reflex. SETTINGS AND DESIGN: A self-controlled clinical trial of biceps T reflex testing at the Electrophysiology Unit of the Department of Physical Medicine and Rehabilitation. METHODS AND MATERIALS: Biceps T reflex was obtained utilizing a hand-held electronic reflex hammer in 50 extremities of 25 healthy volunteers and the effect of elbow position (at 90 degrees , 120 degrees and 150 degrees ) on reflex response was evaluated. STATISTICAL ANALYSIS: Repeated-measures analysis of variance by the General Linear Model and Pearson correlation test procedures. RESULTS: Onset latency was significantly shorter at 120 degrees of elbow position. The maximum amplitude value of biceps T reflex was obtained at 90 degrees of elbow position. Onset latency of the reflex correlated significantly with the height and arm length but not with age. CONCLUSIONS: The electrophysiological measurement of T reflexes is an easy and useful method in the quantification of reflexes, supplying more objective data. However, when performing T reflex studies, the position of the extremity should be taken into consideration to achieve more reliable results.

Adult↗
PubMed1975

Human masseter muscle: H- and tendon reflexes. Their paradoxical potentiation by muscle vibration.

We developed a method for direct electrical stimulation of the masseter nerve in man. Both direct M-reponses and genuine H-reflexes were recorded from the ipsilateral masseter muscle. Muscle vibration that inhibits the Achilles tendon reflex and the soleus H-reflex was found to potentiate the masseter tendon reflex and also the masseter H-reflex. This unexpected contrast may be related to peculiar brain stem circuitry of the masseter reflex mechanism.

Achilles Tendon↗
PubMed1993

The relationship between body height extremes and the conditioned patellar tendon reflex response.

The purpose of this study was to determine the effects of extreme body heights on the conditioned patellar tendon reflex response in an attempt to differentiate between the contributions of supraspinal and spinal mechanisms on long-latency reflex facilitation. Unilateral and conditioned right patellar tendon reflexes were assessed in 10 extremely short males and females and 10 extremely tall males and females. The conditioning stimulus was a contralateral patellar tendon tap and the conditioning intervals were 10, 15, 25, 50, 60, 75, 100, 150, and 300 ms. There was a long-latency facilitation of quadriceps excitability beginning at the 75 ms conditioning interval regardless of the height of the subject. It is hypothesized that the similar conditioned patellar tendon recovery profiles in the extremely short subjects and the extremely tall subjects reflects the activation of a spinal polysynaptic pathway as the predominant mechanism for our long-latency reflex facilitation.

Adolescent↗
PubMed2000

Hyperactive tendon reflexes in spastic multiple sclerosis: measures and mechanisms of action.

OBJECTIVE: To develop new measures of tendon reflexes and evaluate hyperactive reflexes in patients with spastic multiple sclerosis (MS). DESIGN: With the subject relaxed, a hand-held instrumented hammer was used to tap the patellar tendon and record the tapping force, while knee extension torque and quadriceps EMG were recorded isometrically as measures of the reflex response. SETTING: Research laboratory in a rehabilitation hospital. SUBJECTS: Ten spastic MS and 14 healthy subjects. MAIN OUTCOME MEASURES: Tendon tapping force (designated as system input), reflex torque (as output), their dynamic relationship (characterized as system parameters tendon reflex gain, contraction rate, and reflex loop delay), Ashworth scale, and tendon reflex scale. RESULTS: The system parameters provide more repeatable measures than do input or output parameters alone because they quantify the input and output simultaneously and dynamically. Compared with control subjects, MS patients had a significantly lower threshold in tapping force (p = .026), yet their evoked reflex torque was significantly higher (p = .033). Despite significant quadriceps weakness (p < .0001), MS patients had a significantly higher reflex gain (p = .0002) and contraction rate (p = .0002), and shorter reflex loop delay (p = .0046), indicating hyperexcitability of motoneurons and peripheral receptors, and indicating that relatively more of the muscle was activated reflexively, with greater recruitment of larger fast-twitch fibers. Both the reflex gain and rate measures correlated more closely with the Ashworth scale and tendon reflex scale than did the output measures, indicating their potential clinical value. CONCLUSIONS: With appropriate simplification, the method may be used in clinical practice to quantify more precisely the tendon jerk than is currently feasible with standard clinical tests.

Adult↗
PubMed2005

Aging-related neuromuscular changes characterized by tendon reflex system properties.

OBJECTIVE: To quantitatively evaluate changes in neuromuscular reflex system properties that are associated with aging. DESIGN: Controlled, experimental. SETTING: Research laboratory in a rehabilitation hospital. PARTICIPANTS: Fourteen elderly (age, 69.4+/-7.1 y) and 18 young (age, 29.9+/-6.5 y) healthy subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: With the subject relaxed, an instrumented reflex hammer was used to tap the Achilles tendon and record the tapping force, whereas the ankle plantarflexion torque and plantarflexor muscle electromyographic activity were recorded isometrically as measures of the reflex responses. Tendon reflex system properties were evaluated by using system identification techniques. Tendon tapping force was designated as system input and reflex-mediated torque and electromyographic activity as outputs. The dynamic relations between input and output were characterized by the system parameters of reflex-mediated torque and electromyographic gains, contraction and excitation rate, reflex-mediated torque and electromyographic delays, and electromechanic delay. RESULTS: Various aging-related changes were found in the tendon reflex system properties, including decreased tendon reflex gain ( P =.029), slower contraction and half-relaxation rates ( P </=.018), and longer electromyographic activation delay, electromechanical delay and overall torque reflex delay ( P </=.025). In contrast, changes in the electromyographic properties were not significant, except for the longer electromyographic activation delay. CONCLUSIONS: Aging is associated with significant changes in the neuromuscular reflex system properties. The changes were mainly associated with weaker and slower muscle force generation but not with significant decrease in motoneuronal excitability.

Aged↗