F-wave Parameters Research Articles

Differences in Dysfunction of Thenar and Hypothenar Motoneurons in Amyotrophic Lateral Sclerosis.

This study aimed to determine differences in spinal motoneuron dysfunction between the abductor pollicis brevis (APB) and the abductor digiti minimi (ADM) in amyotrophic lateral sclerosis (ALS) patients based on studying F-waves. Forty ALS patients and 20 normal controls (NCs) underwent motor nerve conduction studies on both median and ulnar nerves, including F-waves elicited by 100 electrical stimuli. The F-wave persistence (P < 0.05), index repeating neuron (RN; P < 0.001), and index repeater F-waves (Freps; P < 0.001) significantly differed between the APB and the ADM in the NC participants. For the hands of the ALS patients that lacked detectable wasting or weakness and exhibited either no or mild impairment of discrete finger movements, significantly reduced F-wave persistence (P < 0.001), increased index RN (P < 0.001), and increased index Freps (P < 0.001) were observed in APB in comparison with the normal participants, with relatively normal ADM F-wave parameters. For the hands of ALS patients that exhibited wasting and weakness, the mean F-wave amplitude (P < 0.05), the F/M amplitude ratio (P < 0.05), F-wave persistence (P < 0.001), index RN (P < 0.05), and index Freps (P < 0.05) significantly differed between APB and ADM. The differences in the dysfunction of motoneurons innervating APB and ADM are unique manifestations in ALS patients. The F-wave persistence (P = 0.002), index RN (P < 0.001), and index Freps (P < 0.001) in the APB seemed to differentiate ALS from the NCs more robustly than the ADM/APB Compound muscle action potential (CMAP) amplitude ratio. Thus, F-waves may reveal subclinical alterations in anterior horn cells, and may potentially help to distinguish ALS from mimic disorders.

Learned control over spinal nociception reduces supraspinal nociception as quantified by late somatosensory evoked potentials.

We have recently shown that subjects can learn to use cognitive-emotional strategies to suppress their spinal nociceptive flexor reflex (RIII reflex) under visual RIII feedback and proposed that this reflects learned activation of descending pain inhibition. Here, we investigated whether learned RIII suppression also affects supraspinal nociception and whether previous relaxation training increases success. Subjects were trained over 3 sessions to reduce their RIII size by self-selected cognitive-emotional strategies. Two groups received true RIII feedback (with or without previous relaxation training) and a sham group received false feedback (15 subjects per group). RIII reflexes, late somatosensory evoked potentials (SEPs), and F-waves were recorded and pain intensity ratings collected. Both true feedback groups achieved significant (P < 0.01) but similar RIII suppression (to 79% ± 21% and 70% ± 17% of control). Somatosensory evoked potential amplitude (100-150 milliseconds after stimulation) was reduced in parallel with the RIII size (r = 0.57, P < 0.01). In the sham group, neither RIII size nor SEP amplitude was significantly reduced during feedback training. Pain intensity was significantly reduced in all 3 groups and also correlated with RIII reduction (r = 0.44, P < 0.01). F-wave parameters were not affected during RIII suppression. The present results show that learned RIII suppression also affects supraspinal nociception as quantified by SEPs, although effects on pain ratings were less clear. Lower motor neuron excitability as quantified by F-waves was not affected. Previous relaxation training did not significantly improve RIII feedback training success.

Effect of Motor Imagery on the F-Wave Parameters in Hemiparetic Stroke Survivors.

ObjectiveTo assess the effect of motor imagery, as a rehabilitation method in stroke, on F-wave parameters that undergo changes during upper motor neuron involvement.MethodsTwenty-one fully conscious hemiparetic stroke survivors with a completely plegic hand (power 0/5) and a minimum interval of 72 hours since stroke were recruited into this study. The mean F-wave latency, amplitude, and persistence in the median and ulnar nerves were measured in both the affected and non-affected sides at rest and in the paretic hand during a mental task. Comparison was made between data from the affected hand and the non-affected hand as well as between data from the affected hand at baseline and during motor imagery.ResultsPatients had significantly different F-wave persistence between the affected and non-affected sides (paired t-test, p<0.001). Motor imagery could improve F-wave persistence in both the investigated nerves (paired t-test, p=0.01 for ulnar nerve and p<0.001 for median nerve) and F-response amplitude in the median nerve (paired t-test, p=0.01) of the affected limb.ConclusionThe amplitude and persistence of F-wave were improved during motor imagery, representing F-wave facilitation. This result suggests that motor imagery can restore motor neuron excitability, which is depressed after stroke.

Low sensitivity of F-wave in the electrodiagnosis of carpal tunnel syndrome

ObjectivePrevious studies showed “F-wave inversion” (F-INV) as a sensitive method in the electrodiagnosis of early stage of carpal tunnel syndrome (CTS). This study aimed at evaluating the sensitivity and specificity of F-wave and nerve conduction velocity (NCV) testing in CTS. MethodsWe consecutively enrolled 244 cases and 108 controls. F-waves analysis included: Fwave minimum and mean latencies, F-wave persistence and chronodispersion, mean-F/CMAP amplitude ratio, F-INV. Specificity and sensitivity of F-waves parameters were calculated in the whole sample of CTS patients and by grouping the patients according to CTS severity. Multivariate logistic regression was also performed using F-INV as a dependent variable. ResultsIn the whole sample the sensitivity of F-mean-INV and of median–ulnar NCV comparative testing was 50.8% and 93.7%, respectively. F-INV sensitivity dropped to 8% in CTS early stage. F-INV could be predicted only by distal motor latency of the median nerve. The sensitivity of all F-wave parameters increased only in the most severe stages of CTS. ConclusionsThis study does not confirm the electrodiagnostic usefulness of F-INV in early stage of CTS. All F-wave parameters, including F-INV, are much less sensitive than conventional NCV in CTS electrodiagnosis. F-wave does not add further useful information specifically related to CTS.

Anti-spastic effects of footbaths in post-stroke patients: A proof-of-principle study

ObjectivesTo investigate whether a footbath inhibits spasticity in the hemiplegic lower limbs of post-stroke patients. DesignRandomized, controlled study. SettingRehabilitation education and research hospital. InterventionsTwenty-two post-stroke patients were randomly allocated to control or experimental groups. After relaxing in a supine posture for 30min, the experimental group subject's legs were immersed in 41°C water below the knee joint for 15min, while the control group remained in a resting posture. Main outcome measuresModified Ashworth Scale (MAS) scores of the affected triceps surae muscle and F-wave parameters (i.e., F-wave amplitude, F/M ratio, and F-wave persistence) were recorded before, immediately after, and 30min after each intervention. Physiological parameters were simultaneously monitored to determine the thermo-therapeutic mechanisms and side effects of footbath usage. ResultsAt the time immediately after the intervention, F-wave amplitudes decreased significantly in the experimental group, compared to the control group (p<0.01, difference: −106.8; 95% CI; −181.58 to −32.09). F-wave amplitudes decreased significantly after 30-min intervention in the experimental group, with a total reduction of 161.2μV being recorded compared to 8.8μV increase in the control group (p<0.01, difference: −170.0; 95% CI; −252.73 to −87.33). There were also significant differences between the experimental and control group for both F/M ratio and F-wave persistence, immediately after and 30min after the intervention. Further, there were significant differences between the experimental and control group for the MAS scores immediately after the intervention (p<0.05, difference: −0.72; 95% CI; −1.262 to −0.193), and 30min after the intervention (p<0.05, difference: −0.73; 95% CI; −1.162 to −0.293). ConclusionThese findings demonstrate that the use of footbaths is an effective non-pharmacological anti-spastic treatment for use in stroke rehabilitation.

Effects of isoflurane anesthesia on F‐waves in the sciatic nerve of the adult rat

Nerve conduction studies provide insights into the functional consequences of axonal and myelin pathology in peripheral neuropathies. We investigated whether isoflurane inhalation anesthesia alters F-wave latencies and F-persistence in the sciatic nerve of adult rats. Ten rats were investigated at 3 different isoflurane concentrations followed by ketamine-xylazine injection anesthesia. To assess F-wave latencies, a stimulation paradigm was chosen to minimize H-reflex masking of F-waves. F-wave persistence rates were reduced with 3.5% isoflurane concentration at 4 and 10 Hz supramaximal stimulation and marginally reduced with 2.5% isoflurane when compared with ketamine-xylazine. F-wave amplitudes decreased progressively with rising stimulus frequency in all types of anesthesia and most at 3.5% isoflurane concentration. The type of anesthesia and the stimulus repetition rate have an impact on some F-wave parameters. Higher isoflurane concentrations and repetition rates are not recommended in experimental studies using rat neuropathy models where F-waves are of interest.

Effects of repetitive transcranial magnetic stimulation and intensive occupational therapy on motor neuron excitability in poststroke hemiparetic patients: A neurophysiological investigation using F-wave parameters

Background: The combination protocol of repetitive transcranial magnetic stimulation (RTMS) and intensive occupational therapy (OT) improves motor function of the paretic upper limb in poststroke patients. However, the effect of RTMS/OT on motor neuron excitability remains to be investigated. The purpose of this study was to determine the effect of 15-day application of RTMS/OT on motor neuron excitability in such patients using neurophysiological studies including F-wave parameter measurements. Subjects and Methods: Ten poststroke patients with spastic upper limb hemiparesis were studied (mean age: 57.4 ± 8.1 years, ±SD). Patients were hospitalized for 15 days to receive RTMS/OT. One session of 40-min low-frequency RTMS and two sessions of 120-min intensive OT were provided daily. Neurophysiological studies including F-wave parameters measurements were performed on the days of admission/discharge. Motor function and spasticity of the affected upper limb were evaluated on the same time points. Results: RTMS/OT significantly improved motor function of the affected upper limb. RTMS/OT decreased the modified Ashworth scale (MAS) in the affected upper limb (p < 0.05), but did not change F-wave frequency in either upper limb. However, both F-mean/M ratio and F-max/M ratio significantly decreased in the affected upper limb (all p < 0.05). Conclusions: The 15-day protocol of LF-RTMS/OT produced significant reduction of motor neuron excitability. RTMS/OT can potentially produce significant reduction in upper limb spasticity in the affected upper limb, although this finding should be confirmed in a larger number of patients.

The relationship of median nerve F-wave parameters with severity and subtypes of carpal tunnel syndrome1

F-wave analysis may help affirm or disprove a compression neuropathy. In this study we have analysed the effects of focal median nerve injury on F wave in Carpal Tunnel Syndrome (CTS). We studied 57 patients (100 hands) with clinical and electrophysiological CTS and 31 (62 hands) healthy subjects. Median nerve F-waves were evaluated following 10 supramaximal stimuli and recording from abductor pollicis brevis muscles. Minimum, maximum, and mean F-wave latencies, frequency of the F wave (Fp), chronodispersion (F<formula>_{CD}</formula>), mean F/M amplitude ratios (mF/M-amp) and F-wave conduction velocity (FwCV) were evaluated. The CTS patients showed prolonged F-wave latencies, decreased Fp, and an increase of the F<formula>_{CD}</formula> as compared with normative values. Absent F wave was presented in 8 of 34 hands (23.5%) with severe CTS patients. In the severe group, the FwCV was significantly slower (p< 0.001) and the mF/M-amp was significantly higher (p< 0.001) than that of mild and moderate groups, respectively. Also, the mF/M-amp was significantly greater and Fp was lower in the axonal type than in the demyelinating type. The F<formula>_{CD}</formula> was not different among groups. A strong positive correlations between mMDL with Fmin (r=0.81, p< 0.000), Fmean (r=0.80, p< 0.000) and Fmax (r=0.71, p< 0.000) were revealed. Results support the differing effects of demyelinating and axonal injury on F-waves and suggest that the mF/M-amp ratio and FwCV, which is influenced by neuronal damages in the distal segment of the median nerve, is useful in the discrimination of CTS severity.

Establishment of a method to measure length of the ulnar nerve and standardize F-wave values in clinically normal beagles.

We designed a new method of measuring the length of the ulnar nerve and determining standard values for F-wave parameters of the ulnar nerve in clinically normal beagles. Nerve length must be precisely measured to determine F-wave latency and conduction velocity. The length of the forelimb has served as the length of the ulnar nerve for F-wave assessments, but report indicates that F-wave latency is proportional to the length of the pathway traveled by nerve impulses. Therefore, we measured the surface distance from a stimulus point to the spinous process of the first thoracic vertebra (nerve length 1) and the anterior horn of the scapula (nerve length 2) as landmarks through the olecranon and the shoulder blade acromion. The correlation coefficients between the shortest F-wave latency and the length of nerves 1, 2 or the forelimb were 0.61, 0.7 and 0.58. Nerve length 2 generated the highest value. Furthermore, the anterior horn of the scapula was easily palpated in any dog regardless of well-fed body. We concluded that nerve length 2 was optimal for measuring the length of the ulnar nerve.

Measurement of F wave components in a sample of healthy Iraqis: Normative data

Background: F-waves are late responses often incorporated during performance of nerve conduction studies and have become an integral part of the electrodiagnostic examination. Objective: To study uncommonly measured F-wave parameters and to establish normative data in our country. Materials and Methods: The study included 126 healthy individuals aged between 18 to 55 years. F-waves minimum, mean and maximum latencies, persistence, F-amplitude, F-conduction velocity, chronodispersion, Tacheodispersion, and F-ratio were studied by surface electrodes from the abductor pollicis brevis, abductor digiti minimi, abductor hallucis, and extensor digitorum brevis by stimulating the median, ulnar, tibial, and common peroneal nerves, respectively. Results: Different F-wave parameters were presented in the manuscript. F-wave latencies were correlated with limb length and height. Conclusion: F-wave latencies correlate better to the limb length than the height. The use of F-wave latencies without such correlation may lead to an erroneous conclusion. F-wave parameters should be performed in routine nerve conduction studies.

F-Wave Suppression Induced by Suprathreshold High-Frequency Repetitive Trascranial Magnetic Stimulation in Poststroke Patients with Increased Spasticity

High-intensity and high-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex was carried out in poststroke patients with increased spasticity, and the changes in F-wave parameters in comparison with M-wave parameters induced by rTMS were examined. Ten-hertz rTMS pulses were delivered to the primary motor cortex of the lesion side at 110% intensity of the resting motor threshold, and F-waves were obtained from the first dorsal interosseous muscle. F-waves were recorded before (pre-stim) and immediately after the end of rTMS (post-stim) in poststroke patients. F-wave persistence and F/M Amp.Ratio increased significantly in patients with lesions in upper motor tract as compared with healthy subjects (Wilcoxon rank sum test, p = 0.00023 and p = 0.0073, respectively). After the rTMS application, both F-wave persistence and F/M Amp.Ratio decreased significantly (paired t-test, p = 0.0095 and p = 0.037, respectively). However, the F-wave amplitude did not show a statistically significant variance in poststroke patients. High-frequency suprathreshold rTMS may suppress the F-waves by enhancing the inhibitory effect on spinal excitability through the corticospinal tract, and F-wave persistence and F/M Amp.Ratio can be used to determine the effect of rTMS on patients with increased spasticity.

Practical electrodiagnostic value of F-wave studies in chronic inflammatory demyelinating polyneuropathy

ObjectivesTo ascertain the practical electrodiagnostic value of F-waves in chronic inflammatory demyelinating polyneuropathy (CIDP). MethodsWe evaluated the diagnostic utility of F-waves in 18 prospectively-recruited patients with typical CIDP. Minimum/maximum/mean F-wave latencies, F-wave chronodispersion and F-wave persistence, were determined in median/ulnar/fibular/tibial nerves in patients and compared to controls with axonal neuropathy. ResultsAll latencies were significantly more delayed in CIDP patients. F-wave chronodispersion was significantly greater in median and ulnar nerves and F-wave persistence significantly more reduced in tibial nerves in CIDP patients. Use of these supplementary F-wave parameters was of value in identifying CIDP nerves. However F-wave studies were only of additional benefit to other demyelinating parameters in about 15% of all studied CIDP nerves. ConclusionsF-waves may be diagnostically helpful in CIDP in a minority of nerves without other nerve conduction abnormalities. Analysis of F-wave chronodispersion in upper limb nerves and possibly of F-wave persistence in tibial nerves, may add value to basic minimum F-wave latency studies. SignificanceThese results suggest F-wave analysis may not need to be systematic, for all nerves, in patients with suspected CIDP, especially those intolerant to electrical stimulation. Chronodispersion and persistence may be helpful parameters to consider in addition to minimum latency.

Effect of low-frequency rTMS on motor neuron excitability after stroke

The purpose of this study was to test the effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) over the non-lesional hemisphere on motor neuron excitability of the paretic upper limb in post-stroke patients by electrophysiological examination. Thirteen post-stroke patients with spastic upper limb hemiparesis were studied (age, 57.5 ± 11.1 years; time after stroke, 55.2 ± 51.4 months). Low-frequency rTMS of 1 Hz was applied for 20 min to the motor cortex of the non-lesional hemisphere. The M-response amplitude and F-wave parameters were recorded in the abductor pollicis brevis muscle following stimulation of the median nerve in both the affected and unaffected upper limbs. The F-wave frequency, F-max/M ratio (ratio of maximum F-wave amplitude to M-response amplitude), and F-mean/M ratio (the ratio of mean F-wave amplitude to the M-response amplitude) were measured before and after the 20-min rTMS, analyzed for both limbs. Application of low-frequency rTMS did not result in significant changes in the frequency of F-wave and F-max/M ratio in both upper limbs, but significantly decreased F-mean/M ratio in the affected upper limb (P < 0.005), but not in the unaffected limb. Low-frequency rTMS applied to the non-lesional hemisphere might be potentially useful therapeutically for post-stroke patients with spastic upper limb hemiparesis.

Anti-spastic effects of the direct application of vibratory stimuli to the spastic muscles of hemiplegic limbs in post-stroke patients: A proof-of-principle study

To investigate whether the direct application of vibratory stimuli inhibits spasticity in the hemiplegic upper limbs of post-stroke patients. A randomized controlled study. Thirty-six post-stroke patients. Patients were randomly allocated to the "Rest group", "Stretch group", or "Direct application of vibratory stimuli group". After relaxing in a supine posture for 30 min, subjects received the interventions for 5 min. The Modified Ashworth Scale scores and F-wave parameters were recorded before, immediately after and 30 min after each intervention. The Rest group showed no significant changes in F-wave parameters and Modified Ashworth Scale scores. The Stretch group showed a tendency to decrease in F-wave amplitude and F/M ratio immediately after the intervention, but not 30 min later. The Direct application of vibratory stimuli group showed significant improvements in F-wave parameters and Modified Ashworth Scale scores immediately after the intervention, which remained 30 minutes later. The changes in F-wave parameters and Modified Ashworth Scale scores observed in the Direct application of vibratory stimuli group significantly differed from those in the Rest group and the Stretch group. The direct application of vibratory stimuli has anti-spastic effects in the hemiplegic upper limbs of post-stroke patients.

The effects of circumferential pressure on the soleus muscle F-wave in healthy subjects

Circumferential pressure (CP) was shown to decrease muscle activity in subjects without neuromuscular disorders and in individuals with spinal cord injury and cerebrovascular accidents. The mechanism for this decrease is unknown although it is hypothesized to be spinal in origin. The purpose of this study was to investigate the effect CP has on the soleus F-wave. Results will help determine the mechanism CP uses to effect motoneuron reflex excitability. Thirty-seven healthy volunteers participated. A 16cm air-splint was placed around the calf and during the pressure phase of the experiment it was inflated to 40–45mm Hg. F-waves were evoked by supra maximally stimulating (20%>Mmax) the tibial nerve with a 0.1ms pulse at 0.2Hz using a bipolar surface electrode on the skin of the popliteal fossa. Fifty F-waves were recorded before (baseline), during, and 3) after CP was applied. F-waves were then identified and mean latency, persistence, and mean F/Mmax amplitude ratios were measured and calculated. Friedman Repeated Measures on Ranks tests were conducted on each of the three parameters (p⩽0.05). No statistically significant difference was found for any of the F-wave parameters evaluated. These results were contrary to previous CP studies that observed a significant decrease in muscle activity. Possible reasons for this discrepancy are discussed.

The effect of local corticosteroid injection on F-wave conduction velocity and sympathetic skin response in carpal tunnel syndrome.

The aim of this study was to evaluate the efficacy of steroid injection for the treatment of the carpal tunnel syndrome (CTS), with F-wave parameters and sympathetic skin response (SSR). Seventeen hands of 10 women patients were treated with local steroid injection with 2-month follow-up. All patients underwent single injection into the carpal tunnel. Response to injection was measured nerve conduction studies (NCSs), median nerve F waves, and SSR before and after treatment. To determine the normal values, 42 hands of 21 healthy women were also studied. There was a significant improvement of sensory and motor nerve conduction values when compared to baseline values (P < 0.01). At the end of follow-up period, the median sensory distal latency and the sensory latency differences between the median and the ulnar nerve were improved 35 and 65%, respectively. The maximum, mean F-wave amplitudes and chronodispersion showed a slight improvement with respect to baseline values and controls, but statistical significance was not achieved after treatment. Although no statistically significant improvements were observed in SSR parameters, slightly decreased amplitudes and increased habituation of SSR were noted at the end of the treatment. The present study shows that the local steroid injection results in improvement in NCSs values, but the F-wave parameters were not effectual in short-term outcome of CTS treatment. These findings suggest that the sensory latency differences between the median and the ulnar wrist-to-digit 4 are better parameters in the median nerve recovery after treatment than the median sensory distal latency. Furthermore, the SSR does not seem to be a sensitive method in follow-up of CTS treatment.

Diagnostic Value of the Analysisof F-wave Parameters in Inflammatory Diseases of the Spine

Objective. To analyze the most significant criteria for early detection of radiculopathy in patients with inflammatory diseases of the spine basing on the analysis of F-wave parameters obtained by stimulation electroneuromyography of lower extremities. Material and Methods. Primary F-wave parameters were studied in two groups of patients with inflammatory diseases of the spine: with diagnosed radiculopathy (n = 12), and without radiculopathy (n = 14). Results. The most diagnostically significant parameters of electroneuromyography were F-wave amplitude, minimal velocity, and tacheodispersion. They allow for detection of neurological pathology at early stages of its development when marked clinical symptoms of radiculopathy are not manifested. Conclusion. Diagnostically significant parameters of the wave may be used in preclinical diagnosis of radiculopathy in patients with inflammatory diseases of the spine both for the assessment of initial neurological status and indications for surgical treatment, and for estimation of postoperative dynamics.

A neurophysiological approach to the complex organisation of the spine: F-wave duration and the cutaneous silent period in restless legs syndrome

Objective It is generally accepted that F-wave duration (FWD) and the cutaneous silent period (CSP) are influenced by diminished central inhibition. The aim of this study was to diagnose patients of restless legs syndrome (RLS) with the help of FWD and/or CSP parameters. Methods In all, 24 patients with primary RLS were compared with 31 age- and sex-matched controls. The participants were evaluated based on nerve conduction study (NCS), F-wave parameters (minimum, maximum and mean latency; chronodispersion, persistence and duration; and the ratio of the mean FWD to compound muscle action potential (CMAP) duration), CSP (latency, duration and the ratio of lower-extremity (LE) to upper-extremity (UE) duration that is, silent period ratio (SPR)), the expiration to inspiration ratio (E/I) and sympathetic skin response (SSR). Results There were not any significant differences in NCS, E/I or SSR between the patients and controls. However, FWD was prolonged ( P < 0.0001 for UE and LE) and FWD/CMAP duration was increased in upper and lower extremities ( P < 0.001 for UE and P < 0.0001 for LE). Further, CSP latencies in UE ( P = 0.030) and LE ( P < 0.001) were prolonged, and CSP duration and SPR were significantly reduced in the patient group ( P < 0.0001). Conclusions As both NCS and autonomic test results were in the normal range, abnormalities in FWD and CSP parameters were attributed to the dysfunction of different interneuron groups in the spine. Significance The use of FWD and CSP could aid in the diagnosis of RLS patients in whom conventional electrophysiological procedures are ineffective.

Beneficial effects of footbaths in controlling spasticity after stroke

Footbaths are considered to provide beneficial thermal therapy for post-stroke patients with spasticity, but their anti-spastic effects have not been investigated comprehensively. The present study aimed to evaluate alterations in motor-neuron excitability using F-wave parameters in post-stroke patients with spastic hemiplegia. Subjects' legs below the knee joint were immersed in water at 41 degrees C and F-wave recordings were made over the abductor hallucis muscle before, immediately after, and 30 min after thermal treatment. Antidromic stimulation was performed on the tibial nerve at the ankle. Measurements included F-wave amplitude, F-wave/M-response ratio, changes in modified Ashworth scale (MAS), body temperature and surface-skin temperature. The mean values of both F-wave parameters were higher on the affected side before footbath treatment. In post-stroke patients, the mean values of F-wave parameters were significantly reduced after footbath treatment (P < 0.01). The anti-spastic effects of footbath treatment were indicated by decreased F-wave parameters, in parallel with decreases in MAS. Body temperature was significantly increased both immediately after, and 30 min following footbath treatment in both groups, which appeared to play an important role in decreased spasticity. Surface-skin temperature increased immediately after footbath treatment in both groups and returned to baseline 30 min later. These findings demonstrate that the use of footbaths is an effective nonpharmacological anti-spastic treatment that might facilitate stroke rehabilitation.

A study of F‐waves in patients with unilateral lumbosacral radiculopathy

The F wave, a late response of low amplitude, is widely used in the study of peripheral nerve lesions, and its persistence and latencies are the main parameters that are usually considered. The analysis of repeater F-waves, which are commonly observed in association with focal or generalized motor neuropathy, is not always performed as a standard electrodiagnostic protocol. We recorded and quantified the F waves from 13 healthy subjects and 22 patients with unilateral lumbosacral radiculopathy (ULSR) affecting the L5 or S1 roots. We found differences between the injured and normal sides of patients with ULSR in several F-wave parameters. Taking into consideration the normalized and pooled values of tibial and peroneal nerves in the injured side of patients with ULSR, the minimum and mean latencies were higher (1.05 and 1.04 with respect to 1.00; P < 0.01), the relative amplitude of the F waves was higher (1.95 with respect to 1.00; P < 0.001), and the percentage of repeater F-waves was also higher (4.19 with respect to 1.00; P < 0.001). This latter parameter was the most sensitive to detect lateral differences as indicated by the percentage of change and its high z score. Our results show that the use of F-waves may improve the electrodiagnosis of the ULSR if the number of repeater waves is evaluated given the clear and consistent increase of this variable in patients with lumbosacral root injury.