Simultaneous Contraction Research Articles

The Assessment of Left Ventricular Systolic Asynchrony in Patients with Primary Hyperparathyroidism

Primary hyperparathyroidism (PHP) is associated with a variety of cardiovascular disturbances such as left ventricular (LV) hypertrophy, diastolic cardiac dysfunction, and hypertension. LV asynchrony is defined as the loss of the simultaneous peak contraction of corresponding cardiac segments. The objective of this study was to assess systolic asynchrony in patients with overt hyperparthyroidism. Asynchrony was evaluated in 22 patients with PHP and 24 controls. All the patients and controls were subjected to a tissue synchronization imaging (TSI). The time to regional peak systolic tissue velocity (Ts) in LV by the six-basal-six-midsegmental model was measured on ejection phase TSI images and four TSI parameters of systolic asynchrony were computed. All TSI parameters of LV asynchrony increased in patients with PHP patients compared to the controls: the standard deviation (SD) of the 12 LV segments Ts (37.3±20.6 vs. 21.5±11.1, P=0.01); the maximal difference in Ts between any 2 of the 12 LV segments (111.2±59.8 vs. 70.2±32.1, P=0.01); the SD of the 6 basal LV segments (42.9±36.4 vs. 18.5±13, P=0.003); and the maximal difference in Ts between any 2 of the 6 basal LV segments (89.6±50.5 vs. 48±31.1, P=0.003). Patients with PHP show an evidence of LV asynchrony by TSI. Asynchrony may contribute to the harmful cardiovascular effects of PHP.

Distal Esophageal Spasm in High-Resolution Esophageal Pressure Topography: Defining Clinical Phenotypes

The manometric diagnosis of distal esophageal spasm (DES) uses "simultaneous contractions" as a defining criterion, ignoring the concept of short latency distal contractions as an important feature. Our aim was to apply standardized metrics of contraction velocity and latency to high-resolution esophageal pressure topography (EPT) studies to refine the diagnosis of DES. Two thousand consecutive EPT studies were analyzed for contractile front velocity (CFV) and distal latency to identify patients potentially having DES. Normal limits for CFV and distal latency were established from 75 control subjects. Clinical data of patients with reduced distal latency and/or rapid CFV were reviewed. Of 1070 evaluable patients, 91 (8.5%) had a high CFV and/or low distal latency. Patients with only rapid contractions (n = 186 [17.4%] using conventional manometry criteria; n = 85 [7.9%] using EPT criteria) were heterogeneous in diagnosis and symptoms, with the majority ultimately categorized as weak peristalsis or normal. In contrast, 96% of patients with premature contraction had dysphagia, and all (n = 24; 2.2% overall) were ultimately managed as spastic achalasia or DES. The current DES diagnostic paradigm focused on "simultaneous contractions" identifies a large heterogeneous set of patients, most of whom do not have a clinical syndrome suggestive of esophageal spasm. Incorporating distal latency into the diagnostic algorithm of EPT studies improves upon this by isolating disorders of homogeneous pathophysiology: DES with short latency and spastic achalasia. We hypothesize that prioritizing measurement of distal latency will refine the management of these disorders, recognizing that outcomes trials are necessary.

A 35-day Bed Rest Decreases the Bilateral Deficit During Explosive Efforts of the Lower Limbs

Space flight and bed rest (BR) lead to muscle atrophy and deterioration of neuromuscular function, especially in the postural muscles of the lower limbs. The reduction of neural drive during simultaneous maximal contractions of symmetrical muscles is also one of the main causes of the bilateral deficit (BLD). Indeed, the maximal force exerted with both limbs together (bilateral contraction, BL) is smaller than the sum of the forces developed separately by the two limbs (monolateral contraction, ML) under the same experimental conditions. PURPOSE: We investigated the effects of a 35-day head down tilt BR on the mean force and the BLD of the lower limbs during maximal explosive efforts. METHODS: Ten volunteers performed BL and ML explosive efforts of ∼450 ms on a sledge ergometer, against six different braking forces imposed by an electric motor. Mean force exerted by the right lower limb and surface EMG of right vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF) and gastrocnemius medialis (GM) were recorded. RESULTS: BR decreased: (a) the elevations of the "mean force - braking force" linear regression equations (p<0.05), and the average value throughout all experimental conditions (BL and ML) of mean force by 14.5% (p<0.001); (b) the integrated-EMG average values of VL by 26.5% (p<0.001), RF by 32.3% (p<0.01), BF by 32.3% (p<0.01) and GM by 45.9% (p<0.001); (c) the lean leg volume by 3.7% (p<0.01); (d) the BLD by 5.9% (p<0.001). After BR, the coordination among the four muscles, as determined from an analysis of the integrated-EMG time course, expressed as percentage of that attained at the end of the push (Dispersion Index), became better in BL as compared to ML, contributing to explain the lesser BLD. CONCLUSION: 35 days of BR brought about a decrease in mean force and BLD of the lower limbs. ML efforts were more susceptible to BR than the BL ones, suggesting that common daily activities seem to optimize the motor control of monolateral movements of the lower limbs. Supported by the Italian Space Agency (ASI-OSMA Contract I/007/06/0 Workpackage 1B-32) and the Slovene Ministry of Defence.

The evaluation of esophageal motility in patients with persistent dysphagia after fundoplication

Persistent postoperative dysphagia (PPD) is a relatively rare but troublesome complication of laparoscopic fundoplication in patients with gastroesophageal reflux disease. Although it is mainly attributed to impaired distal esophageal body (EB) function, it may develop in patients with preserved motility as well. Since little is known about the pre- and postoperative motility patterns of such patients we aimed to compare the esophageal motor function in patients with PPD and a matched control group of patients without swallowing problems after fundoplication. Patients, Methods: Eleven patients (M/F 3/8, mean age: 52.6 ys., BMI: 24.2) with PPD after laparoscopic fundoplication were evaluated. Standard water perfusion esophageal manometry was performed before and 3 months after fundoplication in all subjects and results were compared to an age, sex, BMI and preoperative dysphagia score matched group of 11 control patients without PPD. Results: Preoperative esophageal manometry showed similar lower esophageal sphincter (LES) length, pressure, relaxation time, and EB peristaltic wave duration in both groups. The amplitude of contractions in the distal EB were also similar, while patients with PPD had significantly lower amplitudes in the proximal esophagus than controls after dry (25.5 vs. 61.8mmHg, p=0.01) and wet (45.1 vs. 76.7mmHg, p=0.05) swallows. Propagation velocity of the contractions were slower in patients with PPD after wet swallows (2.56 vs. 3.27cm/s, p=0.05). The number of simultaneous contractions tended to be higher in PPD. Postoperatively both groups had similarly improved LES function. In the EB, distal contraction amplitudes were decreased in patients with PPD (95.6 vs. 75.5mmHg, p=0.05) but not in controls, compared to the preoperative values. After fundoplication the number of simultaneous contractions were significantly higher in patients with PPD than in controls. Conclusions: In patients with preserved distal EB contraction amplitudes, decreased peristaltic wave propagation velocity, and proximal amplitudes may be predictive for PPD after fundoplication. Patients with PPD have decreased distal EB contraction amplitudes after fundoplication compared to their preoperative results. TÁMOP421/B09/1, ETT340/09

Transtension to transpression: A study of strain evolution in Andaman Islands based on GPS measurements following Great Sumatra–Andaman Earthquake, 2004

We use campaign mode and continuous GPS data from 2005 to 2008 to examine the evolving strain pattern in Andaman Islands after the Great Sumatra–Andaman earthquake. Two and half years after the earthquake, the post-seismic period changes to inter-seismic period. At Port Blair, post-seismic displacement rate reduced to about 95% with clockwise rotation of azimuths and towards North Andaman, velocity vector gradually rotates towards north with drop in magnitude. The inter-seismic displacement was dominated by trench parallel movement. Strain calculations on inclined transpession model shows deformations at Andaman were highly heterogeneous both in post and inter-seismic periods with dominant strike-slip and dip-slip shearing along with layer parallel shortening and extension. Post-seismic and inter-seismic periods had suffered simultaneous subduction perpendicular extension and contraction leading to transtension and transpression deformational environments respectively. Occurrence of earthquakes during post and inter-seismic periods were results of interplay between simple shear and pure shear components of the strain matrix.

Enteric dysmotility/acquired chronic intestinal pseudoobstruction (ED/CIPO): relationship between symptoms, small intestinal manometric abnormalities and neurohistopathological findings

IntroductionEnteric dysmotility is an important clinical subgroup of the gastrointestinal neuromuscular disorders.1 Of a personal series of 130 patients recorded on our data base 89 have undergone both 24 h...

Changes in regional organization and mobility in the Zuni region of the American Southwest during the Pueblo III and IV periods: insights from INAA studies

The transition from the late Pueblo III (AD 1200–1275) to Pueblo IV (AD 1275–1400) period marks one of the most dramatic eras of demographic and social upheaval in the American Southwest. At this time, much of the northern Southwest was depopulated as thousands of ancestral Pueblo people moved to new homelands. In the Zuni region, this transition included a residential shift from dispersed, largely household-scale settlements to massive, multi-storied pueblos housing hundreds of people and a simultaneous contraction of regional settlement to a central core along the Zuni River and its major tributaries. This article presents a synthesis of our recent independent efforts to utilize instrumental neutron activation analysis (INAA) to investigate changes in social interaction in the Zuni region before and after this transition. We suggest that in addition to significant local and regional settlement shifts, the Pueblo III–IV transition in the Zuni region was accompanied by a major reorganization of pottery distribution networks as clear social boundaries began to emerge between village clusters. More generally, our combined study also highlights the iterative nature of INAA data analysis, the benefits of large sample sizes, and the utility of a diachronic interpretative approach.

Diffuse esophageal spasm: the surgical approach

Diffuse esophageal spasm (DES) is a rare primary motility disorder of unknown cause, that can be found in patients complaining of chest pain and dysphagia and in whom ischemic heart disease and GERD have been excluded. The manometric hallmark of DES is the presence of simultaneous contractions in the distal esophagus alternating with a normal peristalsis. Even at specialized esophageal motility laboratories, DES is considered an uncommon diagnosis. In this review, the authors discuss the clinical and diagnostic aspects of this disease, as well as the possible therapeutic options (medical, endoscopic or surgical therapy). Surgery (esophageal myotomy performed through a thoracotomy or with a thoracoscopic access) seems to have a better outcome than medical or endoscopic treatment, and it is considered "the last resource" in these patients. However, satisfactory results are reported, from highly skilled centers, in only about 70% of treated cases, certainly inferior to those achieved in other esophageal disorders. The role of surgery in this disease requires therefore further study, even if controlled trials are probably difficult to perform, due to the rarity of the disease.

A Unique Esophageal Motor Pattern That Involves Longitudinal Muscles Is Responsible for Emptying in Achalasia Esophagus (Gastroenterology 2010;139:102-111)

Hong et al1 has reported a study entitled A unique esophageal motor pattern that involves longitudinal muscles is responsible for emptying in achalasia in the July 2010 issue of Gastroenterology. Achalasia esophagus is characterized by loss of peristalsis and incomplete esophagogastric junction (EGJ) relaxation. Recent studies showed that there is considerable heterogeneity in the disease entity of achalasia esophagus.2 The symptoms such as dysphagia and chest pain in achalasia patients are related to poor esophageal emptying, and in turn related to impaired lower esophageal sphincter (LES) relaxation and lack of esophageal peristalsis. In achalasia, even though incomplete, esophageal emptying occurs intermittently, irrespective of the gravity. However, the precise mechanism of esophageal emptying has never been studied. In this study, based on a recent high-resolution manometry (HRM) classification proposed by Pandolfino et al,3 achalasia was categorized into 3 subtypes based on the esophageal response to wet swallows: type 1 was defined by simultaneous pressure waves of 30 mmHg and type 3 was defined by spastic simultaneous contractions. The authors evaluated the mechanisms of esophageal emptying in 13 patients with achalasia using simultaneous HRM, multiple intraluminal impedance (MII) and high-frequency intraluminal ultrasonography (HFIUS) images. In the results, based on HRM, the predominant achalasia pattern of type 2 was characterized by a unique motor pattern that consisted of upper esophageal sphincter contraction, simultaneous esophageal pressure (pan-esophageal pressurization [PEP]) and EGJ contraction following wet swallows. HFIUS identified longitudinal muscle contraction of the distal esophagus as the cause of PEP in type 2 achalasia. MII revealed that esophageal emptying occurred intermittently (36% swallows) during the periods of PEP. On the other hand, type 1 achalasia had no emptying and type 3 achalasia had relatively normal emptying during most swallows. Therefore, they concluded that the esophageal emptying in achalasia results from swallow-induced longitudinal muscle contraction of the distal esophagus, which increases esophageal pressure and allows flow across the unrelaxed EGJ.

Analysis of Postural Adjustment Responses to Perturbation Stimulus by Surface Tilts in the Feet-together Position

Base of support (BOS) influences the postural control of upright standing in humans. Since a narrowed BOS in the upright position makes postural control difficult, it is important to evaluate and practice balance with a narrowed BOS. We performed an experimental study to clarify the postural control mechanism in a feet-together position in response to dynamic perturbations. Subjects were 10 healthy young adults. Using an electrically operated platform, tilting perturbation was applied to subjects standing in feet-together position. Perturbation was in four directions: backward, forward, right, and left. Using a motion analysis system and electromyography (EMG), we simultaneously measured the three-dimensional postural change and EMG of seven muscles of the trunk and legs. We obtained joint angular change from the motion analysis and the integrated values of muscle activity and latency of the lower extremities from the EMG. In terms of pitch tilt, the ankle strategy was observed: this involved simultaneous contraction of the ankle muscles as usual in the upright position. In contrast, in terms of roll tilt, ”counterweighting” was observed. We also observed a change in postural control to respond to the narrowed BOS. We found that, unlike the feet-apart position, the feet-together position, narrowing the BOS in the left-right direction causes a prominent change and makes postural control strategy difficult only in response to roll tilt perturbations. In the future, we need to investigate the effectiveness of balance training including roll tilting in the feet-together position in improving balance ability in the left-right direction.

Clinical characteristics and treatment of dystonia

Dystonia is defined as a syndrome of sustained muscle contractions, frequently causing twisting and repetitive movements, or abnormal postures. Its diagnosis is based on clinical characteristics. In dystonia, the pattern of abnormal posture or movement tends to be constant during the short term even if its severity fluctuates. This stereotypy often helps differentiate dystonia from psychogenic reaction. Dystonia may appear only during some specific task (task specificity) especially in its early phase, although it often becomes obscure during the long clinical course, resulting in persistent dystonic posture. Sensory trick or geste antagoniste means the change of severity triggered by some sensory input Overflow phenomenon is the activation of muscles unnecessary to a task, hampering purposeful movement. Symptoms tend to be milder in the morning, with large individual variation of its duration (morning benefit). Symptoms of dystonia may abruptly appear or disappear (flip-flop phenomenon). Cocontraction, believed as an essential feature of dystonia, reflects a loss of reciprocal inhibition of muscle activities, causing involuntary simultaneous contractions of agonists and antagonists. "Negative dystonia," still an unaccepted feature of dystonia, is defined as non-paretic loss of central driving of muscle activities necessary to a task. Apraxia of lid opening/closure, paretic form of hand dystonia, dropped head syndrome, camptocormia, Pisa syndrome, cervical dystonia with limited range of head movement, or mandibular dystonia without cocontractions of masticatory muscles, can be explained with this concept at least in a subset of cases. Treatment of dystonia includes medication, botulinum toxin injection, intrathecal baclofen, surgical intervention, acupuncture and other alternative therapies, rehabilitation, and psychotherapy. Oral medication is usually an adjunct to more potent therapeutic options except for some specific indications like dopa-responsive dystonia. Botulinum toxin is usually the treatment of choice for focal dystonia. Deep brain stimulation can be considered for both focal and non-focal phenotypes of dystonia.

Esophageal body motility in achalasia and Chagas' disease

Previous studies have correlated esophageal body motility findings in idiopathic (IdAc) achalasia and achalasia secondary to Chagas' disease (ChAc) with degree of megaesophagus. The aim of this study was to compare esophageal body manometric data in patients with IdAc and achalasia secondary to Chagas' disease and correlate it with the degree of megaesophagus and symptom duration. One hundred nontreated patients with achalasia, 79% IdAc and 21% secondary to ChAc were compared with regards to age of presentation, duration of symptoms, amplitude and duration of simultaneous contractions, frequency of failed contractions, and degree of megaesophagus. Seventy-one percent of patients were classified as nonadvanced megaesophagus (60 [76%] with IdAc and 11 [52%] with ChAc) and 29% as advanced megaesophagus (19 [24%] with IdAc and 10 [48%] with ChAc, P= 0.04). In IdAc but not in ChAc, the symptom duration was significantly longer in advanced megaesophagus (A) compared with nonadvanced megaesophagus (NA) (34.8 ± 6.3 months vs. 95.4 ± 22.2 months, P= 0.001). There was no difference in amplitude and duration of simultaneous contractions in both achalasia groups (P > 0.05). Duration of contractions were longer in IdAc compared with ChAc in (NA) (P < 0.05), but not in (A). In IdAc but not in ChAc the amplitude of simultaneous contractions decreased with increased esophageal dilatation (P < 0.05). In ChAc but not in IdAC, the duration of contractions increased with esophageal dilatation (P < 0.05). Failed contractions were more frequent in ChAc group (28.6%) than in IdAc (10% -P= 0.03). Patients with ChAc have a higher prevalence of advanced megaesophagus compared with IdAc at diagnosis. In IdAc there was a strong correlation between advanced megaesophagus and longer symptom duration, suggesting disease progression over time, not observed in ChAc in which a more extensive denervation occurs earlier in the disease process.

Does esophageal dysfunction affect the course of treadmill stress test in patients with recurrent angina-like chest pain?

cardioesophageal reflex may increase severity of chest pain and signs of myocardial ischemia on electrocardiogram (ECG), both in patients with and without significant coronary artery stenosis. the aim of the study was to evaluate the relationships between esophageal pH and pressure and clinical and electrocardiographic signs of myocardial ischemia. in 129 consecutive patients with recurrent chest pain, 77 without significant coronary artery lesions in coronary angiography and 52 with myocardial ischemia, panendoscopy, pH-metry, manometry, and treadmill stress test were performed. The prevalence of esophageal disorders was similar in patients with and without significant coronary artery narrowing. Subjects with significant ST interval depression in the stress test had a higher rate of simultaneous esophageal contractions. There were no differences in the results of the treadmill test between patients with and without esophageal disorders. Forty percent of patients with significant coronary artery lesions, who had to stop the test because of chest pain, did not present significant ST interval depression on ECG; however, such depression was observed in 60% of patients with normal coronary angiography. Patients with exercise-provoked chest pain had more pronounced abnormalities in esophageal pH, together with the amplitude and coordination of esophageal contractions. Demographic and clinical factors associated with chest pain and changes in exercise ECG were not evaluated. esophageal disorders are an important cause of chest pain, potentially affecting the results of the treadmill stress test. However, further research is needed to determine the predictors of the cardioesophageal loop activity.

A Case of Symptomatic Diffuse Esophageal Spasm During Multiple Rapid Swallowing Test on High-Resolution Manometry

Diffuse esophageal spasm (DES) is an uncommon motility disorder of unknown etiology in which the abnormal motility has been offered as a possible cause for the patient's dysphagia or chest pain. Esophageal manometry is the gold standard for the diagnosis of DES and the diagnostic hallmark is identification of simultaneous contractions in at least 20% of wet swallows, alternating with normal peristalsis. Recently, a new diagnostic technique, high-resolution manometry has been reported to improve the accuracy and detail in describing esophageal function. We report a female patient with intermittent dysphagia and chest pain occurring only when swallowing a large amount of water. On HRM, this patient had esophageal spasms, increased pressurization front velocity attributable to rapid contractile wave front, associated with symptoms, which were provoked by a multiple rapid swallowing test, and thereby was diagnosed with DES.

Chest Pain During Upper Endoscopy

A 75-year-old male patient visited Seoul St. Mary's Hospital for regular check-up after endoscopic resection of the early gastric cancer. He complained of mild and intermittent dysphagia to solids and liquids for 1 year duration. Frequency of dysphagia increased recently. Previously performed upper endoscopies were reported as normal. After insertion of endoscopy, he complained of severe chest pain. The esophageal mucosa appeared normal but there were severe contractions leading to resistance in advancing the scope in the mid esophagus (Fig. 1). Esophagogram showed a corkscrew appearance on the mid and lower part of the esophagus (Fig. 2). Esophageal manometry disclosed the hypercontractile amplitudes of 365 mmHg (Fig. 3). A normal relaxation of the lower esophageal sphincter ruled out achalasia. Cardiac evaluation revealed nonspecific findings. These findings led to the diagnosis of diffuse esophageal spasm (DES), which was responsible for the chest pain. Chest pain subsided with the treatment of proton pump inhibitor, verapamil and isosorbide mononitrate. Figure 1 Upper endoscopy before (A) and after (B) the development of chest pain. Powerful contraction of mid esophagus is observed in the figure 1B. Figure 2 Corkscrew esophagus on barium esophagogram. Figure 3 Esophageal manometry shows multiple spontaneous simultaneous contractions. The amplitudes of these contractions are particularly high. The pain associated with DES are very variable in severity and sometimes can mimic that of angina pectoris.1 Upper endoscopy is firstly recommended to detect structural causes of dysphagia and noncardiac chest pain. In most affected patients, the esophagus retains the ability to propagate normal peristaltic contractions. As endoscopy has substantial limitations in assessing abnormal esophageal motility in DES, the intraluminal manometry is usually needed for the diagnosis of increased pressure of nonperistaltic contractions.2 The presented case showed interestingly endoscopic findings strongly suggestive of DES along with compatible radiographic and manometric findings.

Intra-left ventricular systolic asynchrony in patients with overt hyperthyroidism

Hyperthyroidism causes a variety of adverse effects on the cardiovascular system. Left ventricular (LV) asynchrony is defined as loss of the simultaneous peak contraction of corresponding cardiac segments. The aim of this study was to assess systolic asynchrony in patients with overt hyperthyroidism. Asynchrony was evaluated in 27 patients with overt hyperthyroidism and 21 controls. All the patients and controls were subjected to a tissue synchronization imaging (TSI). The time to regional peak systolic tissue velocity (Ts) in LV by the six-basal-six-mid-segmental model was measured on ejection phase TSI images and four TSI parameters of systolic asynchrony were computed. All TSI parameters of LV asynchrony increased in hyperthyroid patients compared to controls: the standard deviation (SD) of the 12 LV segments Ts (35.7±14.4 vs 20.1±10.1, P<0.0001); the maximal difference in Ts between any 2 of the 12 LV segments (111.9±40.7 vs 65.9±30.7, P<0.0001); the SD of the 6 basal LV segments (31.2±18.2 vs 16.8±9.7, P=0.01); and the maximal difference in Ts between any 2 of the 6 basal LV segments (76.6±42.0 vs 44.4±25.7, P=0.005). Patients with overt hyperthyroidism present evidence of LV asynchrony by TSI.

Co-contraction modifies the stretch reflex elicited in muscles shortened by a joint perturbation

Simultaneous contraction of agonist and antagonist muscles acting about a joint influences joint stiffness and stability. Although several studies have shown that reflexes in the muscle lengthened by a joint perturbation are modulated during co-contraction, little attention has been given to reflex regulation in the antagonist (shortened) muscle. The goal of the present study was to determine whether co-contraction gives rise to altered reflex regulation across the joint by examining reflexes in the muscle shortened by a joint perturbation. Reflexes were recorded from electromyographic activity in elbow flexors and extensors while positional perturbations to the elbow joint were applied. Perturbations were delivered during isolated activation of the flexor or extensor muscles as well as during flexor and extensor co-contraction. Across the group, the shortening reflex in the elbow extensor switched from suppression during isolated extensor muscle activation to facilitation during co-contraction. The shortening reflex in the elbow flexor remained suppressive during co-contraction but was significantly smaller compared to the response obtained during isolated elbow flexor activation. This response in the shortened muscle was graded by the level of activation in the lengthened muscle. The lengthening reflex did not change during co-contraction. These results support the idea that reflexes are regulated across multiple muscles around a joint. We speculate that the facilitatory response in the shortened muscle arises through a fast-conducting oligosynaptic pathway involving Ib interneurons.

*Poster 158: Changes in Corticospinal Excitability Induced by Simultaneous Isometric Contractions and Paired Associative Stimulation

*Poster 158: Changes in Corticospinal Excitability Induced by Simultaneous Isometric Contractions and Paired Associative Stimulation

Pattern Mining of Multichannel sEMG for Tremor Classification

Tremor is defined as the involuntary rhythmic or quasi-rhythmic oscillation of a body part, resulting from alternating or simultaneous contractions of antagonistic muscle groups. While tremor may be physiological, those who have disabling pathological tremors find that performing typical activities for daily living to be physically challenging and emotionally draining. Detecting the presence of tremor and its proper identification are crucial in prescribing the appropriate therapy to lessen its deleterious physical, emotional, psychological, and social impact. While diagnosis relies heavily on clinical evaluation, pattern analysis of surface electromyogram (sEMG) signals can be a useful diagnostic aid for an objective identification of tremor types. Using sEMG system attached to several parts of the patient's body while performing several tasks, this research aims to develop a classifier system that automates the process of tremor types recognition. Finding the optimal model and its corresponding parameters is not a straightforward process. The resulting workflow, however, provides valuable information in understanding the interplay and impact of the different features and their parameters to the behavior and performance of the classifier system. The resulting model analysis helps identify the necessary locations for the placement of sEMG electrodes and relevant features that have significant impact in the process of classification. These information can help clinicians in streamlining the process of diagnosis without sacrificing its accuracy.

Effect of the artificial somato-autonomic neuroanastomosis on defecation after spinal cord injury and its underlying mechanisms

Objective A new artificial somatic-autonomic neuroanastomosis has been established in male rats with spinal cord injury (SCI). Anorectal manometry and neural retrograde tracing were conducted in such animal model after establishing the regenerated reflex pathway to analyze the mechanisms,and the effects on restoring anorectal function and rectum external sphincter synergetic status. Methods In normal male Sprague-Dawley rats weighing 280-300 g, under anesthesia the rats were subjected to limited laminectomy of L4-L6 vertebrae to expose the spinal cord, and the new reflex pathways were established by intradural microanastomosis of left L4 ventral root to the L6 ventral root while leaving the L4 dorsal root intact to trigger the new defecation reflex pathway. Then L4VR-L6VR formed the foreign nerve root. Three months later the spinal cord was completely transected at the T9-10 level. Eight weeks later the model rats were randomly divided into two groups (n1=8,n2=4). The rats in the group 1 were applied in anorectal manometry, and those in the group 2 for neural retrograde tracing study. Results Stimulation of the L4VR proximal end to the anastomosis and the left sciatic nerve induced rectum to contract, and simultaneously greatly weakened electric activity of external anal sphincter (EAS) ( indicating synergetic relaxation of EAS). But stimulation of the contralateral L6VR evoked simultaneous contraction of rectum and EAS. After FG was injected into the left major pelvic ganglia (MPG) and TMR into the EAS, FG-TMR dual labeled neurons and FG or TMR single labeled neurons were mainly observed in the angulus anterior of L4segment in the model rats. FG-TMR positive neurons were not observed in the spinal cord of the normal rats. Conclusion After establishment of the artificial somato-autonomic neuroanastomosis the regenerated neural pathways can effectively improve the rectum EAS synergetic status and restore the anorectal function.Simultaneous reinnervation of MPG and EAS by one group of the dual labeled neurons in L4 may be the key neural anatomy infrastructure for controllable defecation via the somatic-autonomic reflex pathway. Key words: Somato-autonomic neuroanastomosis; Spinal cord injury; Synergetic defecation