Muscle Activity In Patients Research Articles

Increased expression of VEGF following exercise training in patients with heart failure.

During the last decades several angiogenic factors have been characterized but so far it is unknown whether local muscle exercise training increases the expression of these factors in patients with moderate heart failure. Expression of the major putative angiogenic factor vascular endothelial growth factor (VEGF) at the level of messenger RNA (mRNA) and/or protein was therefore studied before and after 8 weeks of training in patient with chronic heart failure. VEGF mRNA and protein concentrations were determined in skeletal muscle biopsies before and after 8 weeks of one-legged knee extension training in patients with chronic heart failure (New York Heart Association II-III). Exercise training increased the citrate synthase activity and peripheral exercise capacity by 46% and 36%, respectively, in parallel with a two-fold increase in VEGF at both the mRNA (P = 0.03) and protein (P = 0.02) levels The increase in VEGF gene expression in response to exercise training indicates VEGF to be one possible mediator in exercise-induced angiogenesis and may therefore regulate an important and early step in adaptation to increased muscle activity in patient with chronic heart failure.

Quantification of sensory trick impact on tremor amplitude and frequency in 60 patients with head tremor.

Head tremor with an obvious head deviation is the typical clinical picture of tremulous cervical dystonia (TCD), whereas head tremor without any significant head deviation allows for the differential diagnosis of dystonic head tremor (DHT) as well as essential head tremor (EHT). Clinical and polyelectromyographic (poly-EMG) studies have shown a suppression of dystonic muscle activity in patients with TCD performing a maneuver called geste antagonistique. The effect of these trick maneuvers on head tremor has not been investigated in patients with DHT and EHT. We studied the impact of sensory trick maneuvers on head tremor amplitude and frequency clinically by using the tremor subscore of the Tsui scale and by means of computer-based accelerometry in 60 patients with head tremor as their major disorder. Based on clinical data (modified Tsui scale: rating of spontaneous head deviation [rotation + lateroflexion + ante-/retroflexion]), pharmacologic response of tremor (propranolol, primidone, or alcohol), family history (postural hand tremor in first-degree relatives), and poly-EMG findings (reciprocal inhibition in neck muscles during voluntary head rotation), 34 patients were diagnosed as having TCD, 14 were classified as having DHT, and 12 patients were diagnosed as having EHT. Using a clinical rating scale, head tremor amplitudes showed a significant decrease compared with baseline during the performance of sensory trick maneuvers in patients with TCD and DHT, but not in patients with EHT. This clinically observed effect was accompanied by a significant reduction in the mean peak power of the dominant frequency in patients with TCD (decrease by 83%, p = 0.0001) and DHT (decrease by 90%, p = 0.01), but not in patients with EHT (decrease by 6%, p = 0.6). Head tremor frequencies showed no significant changes in relation to the trick maneuvers. We conclude that a significant reduction of head tremor amplitude during a sensory trick maneuver is a useful quantitative criterion to distinguish TCD and DHT from EHT.

Effect of Head Position on Levator Veli Palatini Muscle Activity in Patients with Borderline Velopharynge al Competence/ Incompetenc e

Effect of Head Position on Levator Veli Palatini Muscle Activity in Patients with Borderline Velopharynge al Competence/ Incompetenc e

137. Ashworth Scale Correlates with Thresholds and Amplitudes of Reflex Muscle Activity in Patients with Spastic Hemiparesis Ales Praznikar, Milan Gregonc, Janez Krajnik (all from Ljubljana, Slovenia

137. Ashworth Scale Correlates with Thresholds and Amplitudes of Reflex Muscle Activity in Patients with Spastic Hemiparesis Ales Praznikar, Milan Gregonc, Janez Krajnik (all from Ljubljana, Slovenia

Exteroceptive suppression of temporalis muscle activity in patients with fibromyalgia, tension-type headache, and normal controls

Changes of the second suppressive period (ES2) of the exteroceptive suppression of the temporalis muscle activity are found in patients with chronic tension-type headache (TTH) and are suggested to reflect an abnormal endogenous pain control system. We investigated whether similar changes are found in patients with the fibromyalgia syndrome (FMS) that is also believed to result from disturbed central pain processing. The ES2 values of 27 patients with FMS were compared with those of 18 patients with TTH and 40 healthy volunteers. The duration of ES2 (±SD) in FMS patients was 30.6±7.5 ms and was not significantly different from the control group (33.1±7.8 ms), whereas it was significantly shortened in TTH patients (22.9±11.5 ms). Our results indicate that, despite similar concepts on the pathophysiology of the two chronic pain disorders, there are no comparable changes of this brain stem reflex activity in FMS.

Neck and Abdominal Muscle Activity in Patients with Severe Thoracic Scoliosis

Patients with severe chronic obstructive pulmonary disease (COPD) do not use the sternocleidomastoid muscles when breathing at rest, but have a greater than normal neural drive to the rib-cage inspiratory muscles, the abdominal muscles, and the diaphragm. Yet the increased activation of the abdominal muscles and diaphragm in such patients has only limited mechanical effects, and this has led to the suggestion that the overall increase in neural drive is simply an automatic response of the respiratory system to a greater than resting stimulation. To test this hypothesis, we examined the pattern of respiratory-muscle activation in eight patients with severe thoracic scoliosis (Cobb angle between 100 degrees and 136 degrees). We recorded electromyograms of the sternocleidomastoid, scalene, rectus abdominis, external oblique, and transversus abdominis muscles; esophageal (Pes) and gastric (Pga) pressures; and the anteroposterior (AP) diameter of the abdomen during resting breathing in the seated posture. All patients had invariable phasic inspiratory activity in the scalenes; and five patients had invariable phasic expiratory activity in the transversus; intermittent expiratory activity in the transversus was also recorded in three patients. In contrast, only one patient had invariable phasic inspiratory activity in the sternocleidomastoid, and only one patient had invariable phasic expiratory activity in the external oblique. The decrease in abdominal AP diameter during expiration was commonly associated with a rise in Pga. These observations therefore indicate that the pattern of respiratory-muscle activation in patients with severe thoracic scoliosis is essentially similar to that seen in patients with severe COPD. This supports the concept that the order of recruitment of the respiratory muscles during breathing is an automatic response of the central controller.

Aberrant muscle activation in patients after resection of non-primary motor areas: demonstration by surface electromyography

Two patients presented with a tumor involving mainly the supplementary motor area or the premotor cortex. Shortly after tumor resection, each developed transient impairment of voluntary movements. An electromyogram, with the skin electrodes placed over the muscles of the upper arms and forearms, demonstrated aberrant ipsilateral, contralateral or bilateral muscle activation during unilateral motor tasks in both patients. The bilateral activation was more prominent in the patient who had an intact dominant hemisphere. The present study suggests for the first time the importance of non-primary motor areas of the human brain in activating the proper set of muscles on the proper side of the body.

Isometric abduction muscle activation in patients with rotator tendinosis of the shoulder

Objective: To examine the influence of pain on activation in brief maximal and sustained submaximal isometric abduction in patients with rotator tendinosis of the shoulder. Design: Randomized, controlled experimental trial. Participants: Ten patients with complaints of at least 3 months' duration (median range, 1 to 2 years) and nine healthy controls. Intervention: Patients and controls were randomized into subacromial local anesthetic injection on 2 different days. Methods: The uninvolved shoulder was tested first, elbow flexed 90°, shoulder abducted 45°. The protocol consisted of three brief maximal voluntary contractions (MVCs), followed by a sustained submaximal contraction until exhaustion and three MVCs during a 20-minute recovery period. Electromyography (EMG) was obtained bilaterally from the supraspinatus, infraspinatus, upper trapezius, and middle deltoid muscles. Pain was scored on a visual analogue scale (0 to 100). Results: Mean pain rating on MVC of the involved side of patients was reduced from 28 to 10 by subacromial injection. Mean MVC force improved from 163N to 184N (95% confidence interval for the difference, 14 to 29N). The accompanying EMG amplitude during MVC increased significantly in three of the four muscles examined. Pain, force, and EMG of the uninvolved side and in controls were unaltered. Endurance time and EMG (given as μV) during the submaximal contraction were not influenced by pain. MVC did not fully recover during the postexhaustive period, while the corresponding EMG amplitudes were comparable to values in unfatigued muscle. Conclusion: Pain reduced central motor drive during maximal efforts in the unfatigued state, but no additional reduction was seen after a sustained submaximal contraction.

Altered patterns of abdominal muscle activation in patients with chronic low back pain

This study investigated patterns of abdominal muscle recruitment during the abdominal drawing in manoeuvre in subjects with chronic low back pain (CLBP) and radiological diagnosis of spondylolysis or spondylolisthesis. Data were collected using surface electromyography from 12 physically active subjects with CLBP and 10 controls. The control subjects displayed an ability to preferentially activate internal oblique with minimal activation of upper rectus abdominis during the action of drawing in the abdominal wall. The group with CLBP were unable to achieve this. This finding may reflect the presence of neuromuscular dysfunction in this group. Further study is required to investigate if these findings are linked to the ability of patients with CLBP to provide dynamic stability of their lumbar spine.

Amitriptyline, a combined serotonin and noradrenaline re-uptake inhibitor, reduces exteroceptive suppression of temporal muscle activity in patients with chronic tension-type headache

Although reflexes in human jaw muscles have been extensively studied, the neurotransmitters involved in the regulation of these reflexes are not well known. The aim of the present study was to investigate whether amitriptyline, a combined serotonin and noradrenaline re-uptake inhibitor, modulates the late exteroceptive suppression period (ES2) of temporal muscle activity in chronic tension-type headache. ES2 was recorded with a previously evaluated method and assessed by a blinded observer in 35 patients with chronic tension-type headache. Thereafter, ES2 was recorded in 27 of these patients during a double-blind, placebo-controlled, 3-way crossover trial investigating the prophylactic effect of amitriptyline, the selective serotonin re-uptake inhibitor citalopram, and placebo. ES2 duration was significantly shorter during treatment with amitriptyline than during placebo, P = 0.02, while ES2 duration only tended to be shorter during treatment with citalopram, P = 0.34. ES2 was not significantly correlated to the prophylactic effect of amitriptyline or to a range of clinical and experimental pain parameters. Our results demonstrate that amitriptyline reduces ES2 and indicate that ES2 is modulated by serotonergic as well as noradrenergic neuronal pathways.

Amitriptyline, a combined serotonin and noradrenaline re-uptake inhibitor, reduces exteroceptive suppression of temporal muscle activity in patients with chronic tension-type headache

Although reflexes in human jaw muscles have been extensively studied, the neurotransmitters involved in the regulation of these reflexes are not well known. The aim of the present study was to investigate whether amitriptyline, a combined serotonin and noradrenaline re-uptake inhibitor, modulates the late exteroceptive suppression period (ES 2) of temporal muscle activity in chronic tension-type headache. ES 2 was recorded with a previously evaluated method and assessed by a blinded observer in 35 patients with chronic tension-type headache. Thereafter, ES 2 was recorded in 27 of these patients during a double-blind, placebo-controlled, 3-way crossover trial investigating the prophylactic effect of amitriptyline, the selective serotonin re-uptake inhibitor citalopram, and placebo. ES 2 duration was significantly shorter during treatment with amitriptyline than during placebo, P = 0.02, while ES 2 duration only tended to be shorter during treatment with citalopram, P = 0.34. ES 2 was not significantly correlated to the prophylactic effect of amitriptyline or to a range of clinical and experimental pain parameters. Our results demonstrate that amitriptyline reduces ES 2 and indicate that ES 2 is modulated by serotonergic as well as noradrenergic neuronal pathways.

The effect of the tongue retaining device on awake genioglossus muscle activity in patients with obstructive sleep apnea

Knowledge of how dental appliances alter upper airway muscle activity when they are used for the treatment of snoring and/or obstructive sleep apnea (OSA) is very limited. The purpose of this study was to define the effect of a tongue retaining device (TRD) on awake genioglossus (GG) muscle activity in 10 adult subjects with OSA and in 6 age and body mass index (BMI) matched symptom-free control subjects. The TRD is a custom-made appliance designed to allow the tongue to remain in a forward position between the anterior teeth by holding the tongue in an anterior bulb with negative pressure, during sleep. This pulls the tongue forward to enlarge the volume of the upper airway and to reduce upper airway resistance. In this study, two customized TRDs were used for each subject. The TRD-A did not have an anterior bulb but incorporated lingual surface electrodes to record the GG electromyographic (EMG) activity. The TRD-B contained an anterior bulb and two similar electrodes. The GG EMG activity was also recorded while patients used the TRD-B but were instructed to keep their tongue at rest outside the anterior bulb; this condition is hereafter referred to as TRD-X. The GG EMG activity and nasal airflow were simultaneously recorded while subjects used these customized TRDs during spontaneous awake breathing in both the upright and supine position. The following results were obtained and were consistent whether subjects were in the upright or the supine position. The GG EMG activity was greater with the TRD-B than with the TRD-A in control subjects ( p < 0.05), whereas the GG EMG activity was less with the TRD-B than with the TRD-A in subjects with OSA ( p < 0.01). Furthermore, there was no significant difference between the GG EMG activity of the TRD-A and the TRD-X in control subjects, whereas there was less activity with the TRD-X than with the TRD-A in subjects with OSA ( p < 0.05). On the basis of these findings, it was concluded that the TRD has different effects on the awake GG muscle activity in control subjects and patients with OSA. The resultant change in the anatomic configuration of the upper airway caused by the TRD may be important in the treatment of OSA because such a change may alleviate the impaired upper airway function. (Am J Orthod Dentofac Orthop 1996;110:28-35.)

Abdominal respiratory muscle activity in patients with stable chronic obstructive pulmonary disease

With the purpose of defining the pattern of abdominal respiratory muscle activity in patients with chronic obstructive pulmonary disease (COPD), we studied the electromyogram of the rectus abdominis (RA), the external oblique (EO) and transversus (TM) muscles in 14 patients with different degrees of airways obstruction (FEV1: 41 +/- 12%; FEV1/FVC: 45 +/- 10%; RV: 198 +/- 38%; PaO2: 75.8 +/- 12 y PaCO2: 41.4 +/- 5.7 mmHg). The EMG was obtained by insertion of bipolar electrodes guided by an ultrasound image of the abdominal wall to locate the position of the muscles. The measurements were recorded in supine decubitus position in 5 situations: a) breathing at tidal volume; b) slow expiration until RV; c) with inspiratory load; d) with expiratory load, and e) during relaxed breathing with the arms raised. Recordings were also made in the same situations with 10 patients sitting. Eight patients presented phasic expiratory activity during relaxed breathing (TM activity alone or accompanied by EO). We found no significant differences in degree of hyperinflation or in arterial gases between patients with phasic expiratory activity and those without. There were significant differences between these 2 groups, however, as to degree of airways obstruction, for absolute values of FEV1 (p < 0.02) and in raw values (p < 0.04). Slow breathing until RV recruited muscular activity in 13 patients; the muscles did not operate in unison, however, with TM acting first. Recruitment was also observed when inspiratory and expiratory loads were placed, although in this case the 3 muscles acted simultaneously. Phasic activity was observed in only 2 patients for recordings made with arms raised, at which time there was greater tonic muscle activity. The phasic activity pattern recorded when patients were sitting was very similar to that obtained in supine position. In summary, some patients with stable COPD have phasic expiratory activity of the abdominal muscles when resting. These muscles do not appear to act as a unit and this phasic expiratory activity is related to severity of upper airways obstruction.

Oral Air Pressure and Nasal Air Flow Rate on Levator Veli Palatini Muscle Activity in Patients Wearing a Speech Appliance

Oral Air Pressure and Nasal Air Flow Rate on Levator Veli Palatini Muscle Activity in Patients Wearing a Speech Appliance

Oral air pressure and nasal air flow rate on levator veli palatini muscle activity in patients wearing a speech appliance.

This study was designed to determine if levator veli palatini muscle activity can be elicited by simultaneous changes in oral air pressure and nasal air flow when a speech appliance is in place. The speech appliances routinely worn by 15 subjects were each modified experimentally by drilling a hole in the vertical center of the pharyngeal bulb. The air flow rate into the nasal cavity through the opening in the bulb was altered by changing the circular area of the opening in the bulb from the occluded condition (Condition I), to circular area of 12.6 mm2 (4 mm in diameter; Condition II), and then to 38.5 mm2 (7 mm in diameter; Condition III). Electromyographic activity was measured from the levator veli palatini muscle with changes in nasal air flow rate and oral air pressure. Levator veli palatini muscle activity was correlated with changes in nasal air flow and oral air pressure. Increases in levator veli palatini muscle activity were associated with increases in nasal air flow rate compared to oral air pressure changes. The results indicated that aerodynamic variables of nasal air flow and oral air pressure might be involved in the neural control of speech production in individuals wearing a speech appliance, even if the subjects exhibit velopharyngeal incompetence without using a speech appliance. Also, the stimulating effect of bulb reduction therapy on velopharyngeal function might be achieved through the change in aerodynamic variables in association with the bulb reduction.

Occlusal adjustment and myoelectric activity of the jaw elevator muscles in patients with nocturnal bruxism and craniomandibular disorders.

The effects of occlusal adjustments on the myoelectric activity of the anterior temporal and masseter muscles, with the mandible at rest and during maximal clenching in the intercuspal position (ICP), were studied in 24 nocturnal bruxism patients. Before the occlusal adjustment, the patients were treated with a flat occlusal splint for chronic craniomandibular disorders. The results revealed that within the short term the occlusal adjustment, in terms of increased number of occlusal contacts and teeth in contact in ICP, did not change the postural activity, whereas, on average, the level of activation of the jaw elevators, in terms of normalized electromyogram, increased during maximal clenching in ICP. The increase of activity was more pronounced in the masseter muscle than in the anterior temporal muscle.

Neck muscle activity in patients with severe chronic obstructive pulmonary disease.

The present studies were designed to assess the pattern of activity and the frequency of activation of the neck muscles in patients with chronic obstructive pulmonary disease (COPD). Using concentric needle electrodes, we thus recorded the electromyograms of the scalene, sternocleidomastoid, and trapezius muscles during resting breathing in 40 stable patients with severe chronic airflow obstruction (FEV1 = 0.69 +/- 0.18 L) and hyperinflation (FRC = 228 +/- 40% of predicted); 17 patients were hypercapnic at rest. When breathing in the seated posture, all patients (100%) had strong inspiratory contraction of the scalenes. In contrast, no patient showed inspiratory activity in the trapezius, and only four patients (10%) showed definite, invariable inspiratory activity in the sternocleidomastoid. These two muscles were silent in the supine posture as well, even though the adoption of this posture was associated with an increase in dyspnea in most patients. We conclude, therefore, that in contrast to conventional thinking, most stable patients with severe COPD do not use the sternocleidomastoids or the trapezii when breathing at rest. Additional measurements indicated that the sternocleidomastoid inspiratory activity previously recorded in such patients was in general caused by a cross-contamination from surrounding muscles.

A Preliminary Investigation of the Relationship Between Lumbar Postero-anterior Mobility and Low Back Pain

AbstractIt is widely assumed that there is a relationship between pain, stiffness and muscle activity in patients with low back pain. This preliminary study was designed to begin an investigation of the existence of this relationship. Two subjects with low back pain and six normal subjects participated. The postero-anterior mobility of L3 and L4 was measured together with lumbar extensor muscle EMG. All normal subjects showed negligible muscle activity whereas both low back pain subjects demonstrated elevated EMG levels. In addition, both low back pain subjects were found to have relatively low mobility of L3 and L4 as compared to the normal subjects. Further research to investigate the relationship between these variables is indicated.

Wolff Award 1992. Exteroceptive suppression of temporalis muscle activity in patients with chronic headache and in normal volunteers: methodology, clinical and pathophysiological relevance.

Exteroceptive suppression of temporalis muscle activity was studied in patients with chronic headache and in healthy controls. Among different methods of recording, averaging 10 full-wave rectified EMG responses produces results with acceptable variability and discomfort. The late temporalis exteroceptive suppression period (ES2) is reduced on average in patients with chronic tension-type headache; this finding has been reproduced by several independent laboratories. Mean duration of temporalis ES2 is also diminished, but to a lesser degree, in daily drug abuse headache and, as shown by others, in episodic tension-type headache. It is normal in migraine between attacks, cluster headache and various types of symptomatic headaches. Temporalis ES2 may be decreased in untreated patients with major depression. In healthy volunteers, temporalis ES2 duration is reduced by a short-lasting painful stimulus to peripheral limbs after a delay of 50 to 60 ms, and by a sub-motor threshold electromagnetic stimulation to the contralateral cerebral cortex after a delay of 20 to 30 ms. In contrast, long-lasting trains of peripheral painful stimuli have no effect. Various pharmacological agents are able to modify temporalis ES2. Its duration is increased by 5-HT antagonists, but decreased by 5-HT uptake blockers. Pharmacological effects may differ between controls and patients. Considering these results and available data on the anatomo-functional organization of masticatory reflexes, we postulate that temporalis ES2 is a marker of the excitability of interneuronal nets in the ponto-medullary reticular formation. In chronic tension-type headache, excitability of these interneurons is decreased because of inadequate control by the serotonergic raphe magnus nucleus and the periaqueductal gray matter. Dysfunctioning of the latter structures might be caused by abnormal limbic inputs to the brain stem. Some steps of this pathophysiological hypothesis can be verified by modern neurophysiological techniques.

An evaluation of laryngeal muscle activation in patients with voice tremor.

Eight patients with voice tremor were studied to characterize laryngeal muscle involvement. Electromyographic (EMG) recordings were made from intrinsic laryngeal muscles, simultaneously with some extrinsic laryngeal muscles, respiratory movement, and voice recordings during respiration, whisper, and phonation. Spectral measures were used to determine the tremor frequency and the prominence of spectral peaks in the EMG, respiratory and acoustic signals, while correlation coefficients were computed between pairs of tremulous EMG signals to measure the synchrony of tremor between muscles. The intrinsic laryngeal muscles were tremulous during respiration and speech, with the thyroarytenoid most often involved. Tremor was also detected in some of the extrinsic muscle recordings and the percentage of muscles with tremor was higher during phonation than during whisper or respiration. Time delays were found between tremor oscillations in laryngeal muscles. Because the thyroarytenoid was affected in all the patients studied, botulinum toxin injections may be beneficial in treatment of this voice disorder.