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1.
Muscle Nerve ; 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38963007

RESUMO

INTRODUCTION/AIMS: Conventional F wave analysis involves a relatively uniform physiological environment induced by supramaximal stimulations. The F wave characteristics in a dynamic physiological condition, however, are rarely investigated. This study aimed to improve understanding of F wave properties in the more dynamic process by introducing a novel method to analyze F waves based on the compound muscle action potential (CMAP) scan technique. METHODS: Twenty four healthy subjects participated in the study. The CMAP scan was applied to record muscle responses in the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles, respectively. F wave characteristics including mean F wave amplitude and latency (F-M latency), persistence and activating threshold were quantified. RESULTS: An average of 200 F waves per muscle were obtained from the CMAP scan recording. Weak to moderate correlations between F wave amplitude and stimulating intensity were observed in most of the APB (19 muscles; r = 0.33 ± 0.14, all p < .05) and ADM (23 muscles, r = 0.46 ± 0.16, all p < .05) muscles. Significantly longer mean F latency and lower activating F-threshold were found in the ADM muscles (F-M latency: APB: 25.43 ± 2.39 ms, ADM: 26.15 ± 2.32 ms, p < .05; F-threshold: APB: 7.68 ± 8.96% CMAP, ADM: 2.35 ± 2.42% CMAP, p < .05). DISCUSSION: This study introduces new features of F waves using the CMAP scan technique and identifies differences of F wave characteristics between the hand muscles. The CMAP scan based F waves analysis can be combined with the motor unit number estimation to assess functional alterations in motor neurons in neurological disorders.

2.
Cureus ; 16(5): e60964, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38910735

RESUMO

Background and objective Several recent studies have explored whether F-waves can be a sensitive and useful tool for diagnosing carpal tunnel syndrome (CTS). In light of this, we aimed to measure the minimal F-wave latencies in patients with mild, moderate, and severe electrophysiologically diagnosed carpal CTS, as well as individuals without CTS, to determine at which point this parameter becomes sensitive to the syndrome. Materials and methods Nerve conduction studies were carried out in a room where a temperature of 22-24 °C was maintained. The F-waves of the median nerve in all patients and individuals in the control group were recorded. The F-wave with the highest velocity (minimal F) was categorized into the normal, mild, moderate, and severe groups for statistical analysis. All measurements were performed by the same electrophysiology-experienced neurologist. Results Post-hoc analysis demonstrated that the F latency values of the moderate and severe CTS groups were significantly higher than those of the control group (p<0.001 for all comparisons). Furthermore, the F latency values of the severe CTS group were significantly higher than those of the moderate group (p=0.026). Conclusions Based on our findings, minimal F-wave latency is a reliable indicator of moderate to severe CTS. This sensitivity significantly increases in severe cases while disappearing in the presence of mild CTS.

3.
Heliyon ; 10(9): e30016, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38707302

RESUMO

Since there is an upper limit to skill improvement through the repetition of actual execution, we examined whether motor imagery could be used in combination with actual execution to maximize motor skill improvement. Fingertip dexterity was evaluated in 25 healthy participants performing a force adjustment task using a pinch movement with the left thumb and index finger. In the intervention condition, six sets of repetitions of combined actual execution and motor imagery were performed, while in the control condition, the same flow was performed, but with motor imagery replaced by rest. Changes in the excitability of spinal motoneurons during motor imagery compared to rest were compared in terms of the F/M amplitude ratio. Motor skill changes were compared before and after repeated practice and between the conditions, respectively, using the absolute amount of adjustment error between the target pinch force value and the delivered pinch force value (absolute error) as an index. The results showed that the repetition of exercise practice and motor imagery decreased the absolute error, which was greater than that of exercise practice alone in terms of motor skill improvement. The F/M amplitude ratio for motor imagery compared to rest did not increase. This suggests that motor imagery is involved in the degree of the increase of spinal motoneuron excitability based on the real-time prediction of motor execution and that there may be no need for an increase in excitability during motor skill control.

4.
J Phys Ther Sci ; 36(5): 267-272, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38694006

RESUMO

[Purpose] This study aimed to examine the effects of unilateral vibratory stimulation on contralateral homonymous muscle. [Participants and Methods] The study included 14 participants without a history of any disease. Participants were tested under three separate conditions: vibratory stimulation, pressure stimulation, and rest. F-waves were measured at two time points for 15 seconds in the rest position under each of the testing conditions. [Results] The F/M amplitude ratio analysis showed interactions between the vibratory stimulation‒pressure stimulation and vibratory stimulation‒rest conditions. The F-wave persistence analysis demonstrated interactions between the vibratory and pressure stimulation conditions. Vibratory stimulation significantly decreased the F/M amplitude ratio and F-wave persistence at two time points, before and during the stimulation. [Conclusion] The vibratory stimulation used in this study could suppress the contralateral homonymous muscle tone.

5.
Muscle Nerve ; 69(5): 643-646, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38488222

RESUMO

INTRODUCTION/AIMS: Mental rotation (MR), a tool of implicit motor imagery, is the ability to rotate mental representations of two- or three-dimensional objects. Although many reports have described changes in brain activity during MR tasks, it is not clear whether the excitability of anterior horn cells in the spinal cord can be changed. In this study, we examined whether MR tasks of hand images affect the excitability of anterior horn cells using F-wave analysis. METHODS: Right-handed, healthy participants were recruited for this study. F-waves of the right abductor pollicis brevis were recorded after stimulation of the right median nerve at rest, during a non-MR task, and during an MR task. The F-wave persistence and the F/M amplitude ratio were calculated and analyzed. RESULTS: Twenty participants (11 men and 9 women; mean age, 29.2 ± 4.4 years) were initially recruited, and data from the 18 that met the inclusion criteria were analyzed. The F-wave persistence was significantly higher in the MR task than in the resting condition (p = .001) or the non-MR task (p = .012). The F/M amplitude ratio was significantly higher in the MR task than in the resting condition (p = .019). DISCUSSION: The MR task increases the excitability of anterior horn cells corresponding to the same body part. MR tasks may have the potential for improving motor function in patients with reduced excitability of the anterior horn cells, although this methodology must be further verified in a clinical setting.


Assuntos
Células do Corno Anterior , Corpo Humano , Masculino , Humanos , Feminino , Adulto Jovem , Adulto , Células do Corno Anterior/fisiologia , Músculo Esquelético/fisiologia , Medula Espinal , Nervo Mediano/fisiologia , Potencial Evocado Motor/fisiologia , Eletromiografia
6.
Ann Med ; 56(1): 2317362, 2024 12.
Artigo em Inglês | MEDLINE | ID: mdl-38350436

RESUMO

BACKGROUND: The benefit of oral anticoagulation in atrial fibrillation (AF) is well established for patients at elevated stroke risk, but less clear for those at intermediate risk. We investigated whether analysis of electrocardiogram (ECG) derived fibrillatory waves (F-waves) could help identify patients at risk for stroke and systemic embolism (SSE). METHODS: The Finnish Cardioversion (FinCV) study included patients not on permanent anticoagulation therapy who underwent cardioversion for an acute AF episode. We identified 739 individuals with a valid ECG and complete follow-up data. The maximum amplitudes of the F-waves in leads II and V1 were manually measured from the pre-procedure ECG. Patients were categorized into fine and coarse F-wave groups. The optimal lead and amplitude threshold for grouping were found in an events per person-years analysis. SSE were identified from the patient medical records until either anticoagulation was prescribed, AF was deemed chronic, the patient had deceased, or the end of follow-up. RESULTS: Overall 37 (5.0%) patients suffered SSE during the median follow-up time of 5.4 years (1.9-10.8). Measured from lead V1 the SSE rates per 100 person-years were 1.5 and 0.7 in fine and coarse F-wave groups, respectively. Fine F-waves were observed in 112 (15.2%). Baseline characteristics were similar between the groups. Fine F-wave predicted SSE in a competing risk analysis (SHR 2.34, 95%CI 1.12-4.87, p = .023). Analyses from lead II did not provide significant results. CONCLUSION: Electrocardiographic F-wave amplitude may provide additional information on stroke risk in patients with paroxysmal AF and borderline indications or contraindications for anticoagulation.


Assuntos
Fibrilação Atrial , Acidente Vascular Cerebral , Tromboembolia , Humanos , Fibrilação Atrial/complicações , Fibrilação Atrial/tratamento farmacológico , Eletrocardiografia/métodos , Tromboembolia/epidemiologia , Tromboembolia/etiologia , Tromboembolia/prevenção & controle , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/prevenção & controle , Anticoagulantes/uso terapêutico
7.
Neurol Sci ; 45(2): 735-740, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37584878

RESUMO

OBJECTIVE: Electrodiagnostic testing is an important screening test for myotonic dystrophy type 1 (DM1). Although myotonic discharges are observed on electromyography in cases of DM1, it is difficult to distinguish DM1 from other myotonic disorders clinically. In the present study, afterdischarges, another type of pathological potential revealed by electrodiagnostic testing, were analyzed, and their role in distinguishing DM1 from other myotonic disorders was explored. METHODS: Data from 33 patients with myotonic discharges on electromyography were analyzed retrospectively. According to gene testing, the patients were divided into DM1 (n = 20) and non-DM1 myotonia (n = 13) groups. Afterdischarges were investigated by retrospectively evaluating the electrodiagnostic findings of motor nerve conduction studies, F-waves, and repetitive nerve stimulations. RESULTS: Afterdischarges were observed in 17 of the 20 patients with DM1, with an occurrence rate of approximately 85%. However, afterdischarges were absent in all patients with non-DM1 myotonia. There were significant differences in the occurrence rate between the two groups (P < 0.01). CONCLUSION: Afterdischarges may serve as a suggestive role in clinical diagnosis of DM1. The discovery that DM1 can present with afterdischarges may pave a new way to study the pathogenesis of DM1.


Assuntos
Miotonia , Distrofia Miotônica , Humanos , Distrofia Miotônica/diagnóstico , Distrofia Miotônica/genética , Miotonia/diagnóstico , Miotonia/genética , Estudos Retrospectivos , Eletromiografia , Testes Genéticos
8.
Brain ; 147(2): 406-413, 2024 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-37796028

RESUMO

Neurophysiological methods are used widely to gain information about motor neuron excitability and axon conduction in neurodegenerative diseases. The F-wave is a common biomarker used to test motor neuron properties in the diagnosis of neurological diseases. Although the origin of the F-wave is a subject of debate, the most widely accepted mechanism posits that the F-wave is generated by the backfiring of motor neurons stimulated antidromically from the periphery. In this study, we developed an ex vivo mouse sciatic nerve-attached spinal cord preparation with sensory axons severed. In this preparation, stimulation of the whole sciatic nerve or its tibial branch evoked responses with the electrophysiological signatures of F-waves. Manipulations of synaptic transmission by either removal of extracellular calcium or block of post-synaptic glutamate receptors abolished these responses. These results suggest that F-waves are mediated by spinal microcircuits activated by recurrent motor axon collaterals via glutamatergic synapses.


Assuntos
Doenças do Sistema Nervoso , Fenômenos Fisiológicos do Sistema Nervoso , Animais , Camundongos , Neurônios Motores/fisiologia , Transmissão Sináptica , Sinapses , Medula Espinal , Estimulação Elétrica
9.
J Lab Physicians ; 15(4): 493-497, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37780872

RESUMO

Introduction F wave response, a late response obtained from a motor nerve, can be influenced by various external factors like gender, temperature, height, weight, and limb length, and hence it causes variation in the measured parameters. Since very few studies have studied the impact of arm length on the F wave, this study was conducted to analyze the relation between the arm length on various parameters of F wave and hence to consider the importance of it during conduct of a nerve conduction study. Methods The study was conducted among 40 healthy individuals and 40 diabetics with neuropathy. The arm length was measured in the upper limbs in both the groups and F wave was recorded following a conventional procedure using a standardized instrument. Results This study showed that in the upper limbs of both the groups, there existed a positive correlation for certain parameters like minimum, maximum and mean latencies, persistence, FM latency and M latency, and a negative correlation for chronodispersion. Conclusion F wave parameters should be adjusted for arm length to improve the sensitivity and diagnostic ability of neurological testing.

10.
Heliyon ; 9(10): e20551, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37800073

RESUMO

Background: The F wave waveforms show diversity according to the number and size of re-firing cells, but there is still no analytical method that reflects this feature. We previously reported that five classifications of F waves are obtained from the ulnar nerve. However, the diversity of F waves derived from the lower extremities may not be similar. We therefore compared the diversity of F waves in the upper and lower extremities in healthy subjects. New method: F waves were measured during tibial nerve stimulation in 26 healthy subjects. The amount of amplitude decrease was calculated from the amplitude value after the additive averaging process and based on the average amplitude value of each stimulus, and the relationship between the peak latency and density was examined. Results: The amount of amplitude decrease due to the additive averaging process was negatively correlated with the density of negative peaks. The diversity of F waves could be categorized into four class based on the histograms. Comparison with existing method: The new method uses a novel additive average method that reflects the diversity of F waves. Furthermore, it uses a histogram to visualize the cancellation between waveforms. Conclusion: We developed an analysis method that reflects the diversity of F waves in a novel manner, which visualizes cancellation between waveforms using a histogram.

11.
Turk J Phys Med Rehabil ; 69(3): 309-316, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37674799

RESUMO

Objectives: This study investigated whether peroneal nerve F-wave persistence increased when the Jendrassik maneuver (JM) was performed, aiming to obtain information about the physiology of F-waves and JM. Patients and methods: Thirty healthy individuals (HIs; 17 females, 13 males; mean age: 33.6±8.2 years; range, 23-50 years) were included in the prospective experimental study conducted between June 15, 2021, and December 15, 2021. Nerve conduction studies of peroneal, superficial peroneal, posterior tibial, and sural nerves were performed in one extremity of each HI. The peroneal nerve F-wave study was performed at rest (Study 1), during JM (Study 2), and after JM (Study 3). F-wave persistence of the peroneal nerve, maximum F-wave amplitude (ampF-wavemax), mean F-wave amplitude (ampF-wavemean), minimum F-wave latency, and the ratio of ampF-wavemean to maximum M amplitude (F/M ratio) were analyzed. Results: The mean peroneal nerve F-wave persistence in Study 1, Study 2, and Study 3 was 28.7±23.9%, 52.3±32.1%, and 34.7±29.0%, respectively. F-wave persistence in Study 2 was higher compared to Studies 1 and 3 (p<0.001 and p<0.001, respectively). Moreover, ampF-wavemax, ampF-wavemean, and F/M ratio in Study 2 were higher than Studies 1 and 3 (p=0.026 and p=0.021 for ampF-wavemean; p=0.015 and p=0.003 for ampF-wavemax; p=0.033 and p=0.015 for F/M ratio, respectively). F-wave persistence in Study 2 was positively correlated with ampF-wavemax and ampF-wavemean (p<0.001, r= 0.717; p<0.001, r=0.786, respectively). Conclusion: This study demonstrated that JM increased F-wave persistence and amplitude. Jendrassik maneuver may show its effect through motor neuron excitability.

12.
Muscle Nerve ; 68(3): 329-333, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37439375

RESUMO

INTRODUCTION/AIMS: Pancreatic islet transplantation (ITx) is increasingly used in patients with brittle type 1 diabetes (T1D). If successful, ITx results in insulin-free euglycemia, but its application is limited by a need for lifelong immunosuppression. The aim of this study was to assess the long-term effects of ITx on the occurrence and course of polyneuropathy in a cohort of patients with brittle T1D. METHODS: In this prospective, single-center study, 13 patients (4 males and 9 females) with brittle T1D had a baseline neurological exam with the calculation of Utah Neuropathy Scale (UNS) and a limited nerve conduction study before ITx, and about yearly after in the patients who achieved insulin independence. RESULTS: Patients were followed for a period of 17 to 133 months. There was no significant difference between UNS and nerve conduction study parameters at baseline and at the end of follow-up, except for significant decreases in peroneal (50.34 ± 6.12 vs. 52.42 ± 6.47 ms, P = 0.005) and ulnar (27.5 ± 2.15 vs. 29.45 ± 2.10 ms, P = 0.009) F-wave latencies and an increase in ulnar sensory nerve conduction velocity (49.98 ± 6.27 vs. 47.19 ± 5.36 m/s, P = 0.04). DISCUSSION: If successful, ITx has a good long-term safety profile for peripheral nerve toxicity, and a favorable effect on diabetic neuropathy.


Assuntos
Diabetes Mellitus Tipo 1 , Neuropatias Diabéticas , Transplante das Ilhotas Pancreáticas , Polineuropatias , Masculino , Feminino , Humanos , Transplante das Ilhotas Pancreáticas/métodos , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/cirurgia , Estudos Prospectivos , Insulina , Condução Nervosa
13.
Clin Neurophysiol Pract ; 8: 49-57, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37008279

RESUMO

Objective: To establish the utility of the additional evaluation of the P15 potential generated at the greater sciatic foramen in the tibial nerve somatosensory evoked potentials (SEPs) in diagnosing lumbar spinal stenosis (LSS). Methods: We retrospectively reviewed tibial nerve SEP findings in patients having MRI-confirmed LSS at the cauda equina or conus/epiconus region. P15 and N21 potentials were recorded and the following findings were defined as localizing abnormalities: 1) normal P15 latency either with prolonged P15-N21 interval or with absent N21; 2) decreased ratio of the N21 amplitude to P15 amplitude. As non-localizing abnormalities, N21 and P38 latencies were also evaluated. Tibial nerve F-wave findings were also investigated. Results: According to the entry criteria, 18 patients were included, 15 with cauda equina lesions and 3 with conus/epiconus lesions. Localizing abnormalities in SEPs were found in 67% of patients, achieving significantly higher sensitivity than delayed P38 latency (28%), and higher sensitivity than N21 abnormalities (39%), though this was not significant. Localizing abnormalities were observed even in 6 out of 11 patients lacking both sensory symptoms and signs. Tibial nerve F-wave was abnormal in 36% of 14 patients with F-wave examinations, whereas the localizing abnormalities in SEPs were found in 64% of the same patient population. P15 amplitude was depressed in 4 patients (22%), which may indicate the involvement of the dorsal root ganglion in LSS, although its latency was normal even for these patients. Conclusions: Tibial nerve SEPs with the recording of P15 and N21 potentials achieved sufficiently high sensitivity in diagnosing LSS. They have the advantage over F-wave in that they can localize the lesion at the cauda equina or conus/epiconus level. Significance: Tibial nerve SEPs are promising in evaluating LSS, especially in documenting sensory tract involvement in cases lacking sensory symptoms/signs.

14.
Cureus ; 15(2): e35254, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36968912

RESUMO

Although isolated lower leg pain (LPP) without neurological deficit is frequently encountered in clinical practice, some of its aspects remain underexplored in the literature. There is contrasting evidence supporting the use of late responses, namely, F-waves and A-waves, in the assessment of nerve root damage. We describe the case of a 29-year-old female who presented with pain in the left calf. Neurological investigations were only significant for a positive straight leg raise test on the left side. F-wave studies of the left tibial nerve at distal and proximal points of stimulation showed the presence of the A-wave preceding the F-wave, the duration of which was prolonged. One year later, the patient reported new-onset left-sided low back pain with radiation to the gluteal area that appeared after a 10-hour airplane flight. Low back and calf pain were resolved with manipulative therapy. A-waves that had been recorded before F-waves were now no longer detectable. The presence of a neuropathic radicular component was accompanied by subclinical damage to motor fibers, as detected by routine F-waves studies. This case report illustrates the utility of integrating F-wave duration and the presence of A-waves into clinical, neurophysiological, and neuroimaging data in determining pain-generating structures in isolated LLP.

15.
Exp Brain Res ; 241(2): 527-537, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36622384

RESUMO

The F-wave is a motor response elicited via the antidromic firings of motor nerves by the electrical stimulation of peripheral nerves, which reflects the motoneuron pool excitability. However, the F-wave generally has low robustness i.e., low persistence and small amplitude. We recently found that motor point stimulation (MPS), which provides the muscle belly with electrical stimulation, shows different neural responses compared to nerve stimulation, e.g., MPS elicits F-waves more robustly than nerve stimulation. Here, we investigated whether F-waves induced by MPS can identify changes in motoneuron pool excitability during handgrip and motor imagery. Twelve participants participated in the present study. We applied MPS on their soleus muscle and recorded F-waves during eyes-open (EO), eyes-closed (EC), handgrip (HG), and motor imagery (MI) conditions. In the EO and EC conditions, participants relaxed with their eyes open and closed, respectively. In the HG, participants matched the handgrip force level to 30% of the maximum voluntary force with visual feedback. In the MI, they performed kinesthetic MI of plantarflexion at the maximal strength with closed eyes. In the HG and MI, the amplitudes of the F-waves induced by MPS were increased compared with those in the EO and EC, respectively. These results indicate that the motoneuron pool excitability was facilitated during the HG and MI conditions, consistent with findings in previous studies. Our findings suggest that F-waves elicited by MPS can be a good tool in human neurophysiology to assess the motoneuron pool excitability during cognitive and motor tasks.


Assuntos
Potencial Evocado Motor , Força da Mão , Humanos , Potencial Evocado Motor/fisiologia , Músculo Esquelético/fisiologia , Neurônios Motores/fisiologia , Imagens, Psicoterapia , Estimulação Elétrica , Eletromiografia/métodos
16.
Pacing Clin Electrophysiol ; 46(6): 515-518, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36690018

RESUMO

The 12-lead electrocardiogram (ECG) is a fundamental modality to help determine the mechanism and the localization of atrial tachycardias (ATs). Although macroreentrant ATs and focal ATs typically show F-waves and discrete P-waves respectively on the 12-lead ECG, this is not universally the case in scar-related ATs.1, We present three cases clearly showing the discrepancy between the AT morphology on the 12-lead ECG and the AT-mechanism.


Assuntos
Ablação por Cateter , Taquicardia Atrial Ectópica , Taquicardia Supraventricular , Humanos , Cicatriz , Eletrocardiografia
17.
Muscle Nerve ; 67(3): 236-238, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36576113

RESUMO

INTRODUCTION/AIMS: Conventional recording of F-waves from the vastus lateralis muscle causes severe pain in some subjects. Thus, we aimed to investigate the effects of the stimulation frequency on pain and F-wave parameters when recording F-waves from this muscle and to develop a method for recording F-waves from the vastus lateralis muscle that causes minimal pain. METHODS: The subject's femoral nerve was electrically stimulated at 0.5 or 0.2 Hz 30 times, while F-waves were recorded from the vastus lateralis muscle. Pain intensity was measured immediately using a visual analog scale. In addition, the visual analog scale, F-wave persistence, F-wave latency, and F/M amplitude ratio were compared between F-wave recordings with 0.5-Hz electrical stimulation and those with 0.2-Hz electrical stimulation. RESULTS: Eleven healthy men participated in this study. The visual analog scale and F-wave persistence decreased when electrical stimulation at 0.2 Hz was applied compared with electrical stimulation at 0.5 Hz. DISCUSSION: Electrical stimulation at 0.5 Hz increased pain due to temporal summation. However, electrical stimulation at 0.2 Hz did not cause temporal summation, suggesting reduced pain and excitability of the alpha motor neuron pool.


Assuntos
Dor , Músculo Quadríceps , Masculino , Humanos , Músculo Quadríceps/fisiologia , Eletromiografia/métodos , Estimulação Elétrica/métodos , Nervo Femoral/fisiologia
18.
Front Physiol ; 13: 976925, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36200057

RESUMO

Background: The autonomic nervous system (ANS) is known as a potent modulator of the initiation and perpetuation of atrial fibrillation (AF), hence information about ANS activity during AF may improve treatment strategy. Respiratory induced ANS variation in the f-waves of the ECG may provide such information. Objective: This paper proposes a novel approach for improved estimation of such respiratory induced variations and investigates the impact of deep breathing on the f-wave frequency in AF patients. Methods: A harmonic model is fitted to the f-wave signal to estimate a high-resolution f-wave frequency trend, and an orthogonal subspace projection approach is employed to quantify variations in the frequency trend that are linearly related to respiration using an ECG-derived respiration signal. The performance of the proposed approach is evaluated and compared to that of a previously proposed bandpass filtering approach using simulated f-wave signals. Further, the proposed approach is applied to analyze ECG data recorded for 5 min during baseline and 1 min deep breathing from 28 AF patients from the Swedish cardiopulmonary bioimage study (SCAPIS). Results: The simulation results show that the estimates of respiratory variations obtained using the proposed approach are more accurate than estimates obtained using the previous approach. Results from the analysis of SCAPIS data show no significant differences between baseline and deep breathing in heart rate (75.5 ± 22.9 vs. 74 ± 22.3) bpm, atrial fibrillation rate (6.93 ± 1.18 vs. 6.94 ± 0.66) Hz and respiratory f-wave frequency variations (0.130 ± 0.042 vs. 0.130 ± 0.034) Hz. However, individual variations are large with changes in heart rate and atrial fibrillatory rate in response to deep breathing ranging from -9% to +5% and -8% to +6%, respectively and there is a weak correlation between changes in heart rate and changes in atrial fibrillatory rate (r = 0.38, p < 0.03). Conclusion: Respiratory induced f-wave frequency variations were observed at baseline and during deep breathing. No significant changes in the magnitude of these variations in response to deep breathing was observed in the present study population.

19.
BMC Res Notes ; 15(1): 297, 2022 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-36085097

RESUMO

OBJECTIVES: F wave is one of the nerve conduction studies, mainly used to study the proximal pathway of peripheral nerves. One of its applications is dynamic assessment, i.e., before and after physical activity, when symptoms develop in some patients. Best to our knowledge, few studies evaluate normal dynamic F wave values in healthy individuals. This study aims to determine and compare normal values of several parameters of Compound Muscle Action Potential (CMAP) and F waves of tibial nerves dynamically before and after physical activity in the lower extremities of 34 normal subjects. These parameters were recorded before and after 15 min of continuous walking at intervals of 1, 5, and 10 min after the end of physical activity. RESULTS: Normal values of CMAP onset latency and amplitude, minimum, maximum, and mean latency of 10 F waves, F chronodispersion, and F persistence were dynamically collected before and during 10 min after physical activity in three phases. Some of the parameters showed significant changes (P < 0.05). Although physical activity showed statistically significant effects on some CMAP and F wave parameters (especially F chronodispersion) in normal subjects, none of them exceeded the normal clinical values introduced in the literature.


Assuntos
Exercício Físico , Músculos/fisiologia , Caminhada , Potenciais de Ação , Nível de Saúde , Humanos , Extremidade Inferior
20.
Cureus ; 14(8): e28242, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36158375

RESUMO

Background There are many physiological changes that accompany aging. Slowing of muscle contraction, alteration of muscle metabolism and neuromuscular junction, and reduction of nerve conduction velocity (NCV) are among these physiological changes. The present study was conducted to elucidate the effect of physiological factors like gender, height, and Body Mass Index (BMI) on motor and sensory nerve conduction study (NCS) of the upper limb and find out the normal data for healthy elderly subjects in central India. Methods A cross-sectional study among 382 healthy adult participants of central India aged 60 years and above. The study was carried out in the department of Physiology, Acharya Vinoba Bhave Rural Hospital, Wardha, India, from July 2017 to June 2022. An NCS was performed using the Neuron Spectrum 5 machine (Neurosoft, Ivanovo, Russia). A Microsoft Excel spreadsheet (Microsoft Corporation, Redmond, Washington, United States) was used to tabulate the information gathered. For statistical analysis, IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, New York, United States) was used. Results All NCS parameters were greater in males as compared to females. As age advances, longer distal motor latency (DML) and F-wave minimum latency, decreasing amplitude, and slowing of conduction velocity (CV) were observed. As height increases, increasing DML and F-wave minimum latency, decreasing amplitude, and slowing of CV were observed. Higher BMI was found to be associated with lower amplitudes and slowing of CVs. Conclusion Age and height have a negative influence on amplitude and CV is a positive influence on DML and F-min latency. Higher BMI has a negative influence on amplitude and CV.

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