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Biomedical subjects

M Pozzo

Publications and source records attributed to M Pozzo.

11 recordsLinked to original sources

Relationship between perceived exertion and mean power frequency of the EMG signal from the upper trapezius muscle during isometric shoulder elevation.

The aim of the study was to investigate the relationship between a fatigue-induced increase of perceived exertion in the neck with a decrease of mean power frequency (MPF) in the surface electromyography (sEMG) signal during repeated shoulder elevation endurance tasks. About Thirty-two healthy women (age range 20-62) performed two maximum 6-min shoulder elevation endurance tasks at 30% of their maximal voluntary contraction (MVC) level, separated by a rest of 6 min. During these exercises, perceived exertion was estimated using the Borg scale (range 0-10), whereas the MPF of the sEMG signal from the upper trapezius was simultaneously detected. Linear regression analysis was applied over time for each trial and subject for both MPF and Borg scale rating values. The MPF was normalized by the intercept of the linear regression analysis. The resulting slopes of normalized mean power frequency (nMPF) and Borg scale rating were correlated with each other by linear regression for both trials. In order to investigate the individual behavior of fatigue effects between trials, Delta (trial 2-trial 1) slopes of nMPF and Borg scale ratings were calculated for each subject. These slopes of nMPF and Borg scale ratings were correlated with each other as well by linear regression. The increase of Borg scale ratings, as well as the decrease of nMPF, were significantly higher in trial 2 than trial 1 (P<0.01). The results show a linear correlation between slopes of nMPF and Borg scale ratings for both trials 1 and 2 (r=0.76, P<0.01). Trial-to-trial slopes (Delta (trial 2-trial 1)) of nMPF and Borg scale rating, were also significantly correlated (r=0.68, P<0.05). Thus, the individually sensed increase of perceived exertion in the neck during trial 2 was accompanied by a simultaneously higher detected decrease of nMPF. These findings indicate a close relationship between subjective perception of exertion in the neck and objectively assessed muscle fatigue of the upper trapezius.

Adult↗

Multichannel surface EMG for the non-invasive assessment of the anal sphincter muscle.

BACKGROUND/AIMS: This work focuses on recording, processing and interpretation of multichannel surface EMG detected from the external anal sphincter muscle. The aim is to describe the information that can be extracted from signals recorded with such a technique. METHODS: The recording of many signals from different locations on a muscle allows the extraction of additional information on muscle physiology and anatomy with respect to that obtained by classic bipolar recordings. Multichannel EMG methods have been recently developed for the assessment of the external anal sphincter. An anal probe was used in this study to record signals at different depths within the anal canal during contractions at different effort levels. The plug is 150 mm in length and 14 mm in diameter, holding a circumferential array of 16 equally spaced silver bar electrodes, located at a distance of 20 mm from the probe tip and aligned with the probe axis. RESULTS: Information about localization of the innervation zone, fiber length, EMG amplitude, muscle fiber conduction velocity and single motor unit analysis can be obtained from the signals recorded with the circumferential array by means of innovative signal processing techniques. CONCLUSIONS: The type of information extracted from multichannel surface EMG signals cannot be obtained with other currently available techniques. The technological innovation described in this work is promising for a further insight into the investigation of pelvic floor pathologies and rehabilitation treatments.

Anal Canal↗

Muscle-fiber conduction velocity estimated from surface EMG signals during explosive dynamic contractions.

Muscle-fiber conduction velocity (CV) was estimated from surface electromyographic (EMG) signals during isometric contractions and during short (150-200 ms), explosive, dynamic exercises. Surface EMG signals were recorded with four linear adhesive arrays from the vastus lateralis and medialis muscles of 12 healthy subjects. Isometric contractions were at linearly increasing force from 0% to 100% of the maximum. The dynamic contractions consisted of explosive efforts of the lower limb on a sledge ergometer. For the explosive contractions, muscle-fiber CV was estimated in seven time-windows located along the ascending time interval of the force. There was a significant correlation between CV values during the isometric ramp and explosive contractions (R = 0.75). Moreover, CV estimates increased significantly from (mean +/- SD) 4.32 +/- 0.46 m/s to 4.97 +/- 0.45 m/s during the increasing-force explosive task. It was concluded that CV can be estimated reliably during dynamic tasks involving fast limb movements and that, in these contractions, it may provide important information on motor-unit control properties.

Adult↗

Sixty-four channel wearable acquisition system for long-term surface electromyogram recording with electrode arrays.

The use of mono- and bi-dimensional electromyogram (EMG) electrode arrays for the assessment of the neuromuscular system can provide an insight into muscle physiology not achieved with classical bipolar surface EMG. Among the advantages of multichannel EMG detection, there is a) the possibility of estimating muscle fibre conduction velocity, even during motor tasks, and b) the possibility to increase the number of detection points on a muscle, improving the performance of pattern-based EMG decomposition methods. For these reasons, the development and use of multichannel surface EMG devices and techniques were chosen as the primary goals within the European RTD Project 'Neuromuscular assessment in the elderly worker' (NEW). The specific requirements of Project NEW called for the availability of a user-friendly, small-sized EMG acquisition system for field use, suitable for multichannel EMG recording using electrode arrays from one or more muscles. A market survey established that none of the commercially available EMG acquisition systems featured all the desired specifications, nor could they be easily adapted for specific use. The paper describes the design of an innovative acquisition system for long-term multichannel EMG recording fulfilling these requirements and comprising adhesive electrode arrays for artifact-free EMG acquisition during work activity and a portable, user-friendly, battery-powered acquisition system for multichannel EMG recording and storage on a removable PCMCIA card. The system has been used extensively within Project NEW for laboratory and field tests and can find applications in other fields of basic and applied research, including ergonomics, occupational and sports medicine.

Ambulatory Care↗

[Incidence of complications of thyroid surgery].

BACKGROUND: Thyroid surgery presents a low incidence of complications. Death is certainly a rare, or even exceptional event. Hypoparathyroidism, above all if definitive, is the main complication of total thyroidectomy with percentages that very between 0 and 10% in the literature (average 2%). METHODS: The incidence of recurrent lesions varies between an improbable 0% to 8%, whereas lesions to the superior laryngeal nerve are relatively frequent, but often undervalued. Dysphagia, although always transient, presents a high risk of pneumonia ab ingestis and severe dehydration. Hemorrhage has an incidence of 0.1-3.8% and infection is reported in approximately 1% of cases. The permanent and recurrence nature of thyroid pathology in literature is between 5 and 11%, resulting from inadequate or sometimes useless surgery. Hypothyroidism is the logical consequence of total thyroidectomy. In the light of these data we have re-examined 300 operations involving thyroid pathology performed by the same team using the same method over the past 4 years (82% females, 18% males). 33% of the cases presented benign euthyroid nodular pathology, 27% hyperfunctioning benign nodular pathology, 2.6% Flajani-Basedow-Graves disease, 9% were adenomas, 7% were differentiated carcinomas, 2% anaplastic carcinomas and 0.7% medullary carcinomas. 99 extracapsular total loboisthmectomies, 135 total extracapsular thyroidectomies and 66 subtotal thyroidectomies were performed. RESULTS: The following complications were observed: 31/300 symptomatic hypocalcemias of which 25 were transient and 6 (2%) were definitive but easily controlled with treatment; 9 recurrent monoplegias out of 501 isolated recurrent forms of which 4 (0.8%) was permanent; 5/300 (1.7%) postoperative dysphagias associated with recurrent monoplegia in 4 cases. Damage to the external branch of the superior laryngeal nerve was suspected in 11/300 cases (3.7%). Postoperative hemorrhage occurred with an incidence of 1.3%, whereas the incidence of wound infection and serous collection was 1.7%. Moreover, persistent hyperthyroidism after subtotal bilateral thyroidectomy was observed secondary to toxic plurinodular struma. A case of paralysis of the right ulnar nerve, when the arm was adducted, was observed on the operating table, but regressed after about 4 months. Mortality was zero. CONCLUSIONS: Thyroid surgery is still hampered by a relatively low percentage of complications, which are probably still the result of various technical limitations, and it appears difficult to reduce these, let alone eliminate them completely.

Adolescent↗

[Intestinal perforation caused by a toothpick].

Intestinal injuries are pathologies frequently caused by toothpicks. In literature are reported serious damage to the cardiovascular system, lung and systemic fatal sepsis. In literature are also reported some deaths caused by delayed diagnosis. The authors report two cases of intestinal perforation by toothpick. Both patients had accidentally swallowed the toothpick. The clinical state was compatible with acute abdomen in a 59 year old psychopathic patient and acute appendicitis in a 27 year old patient. The aim of this paper is to emphasize the importance of a careful anamnesis for detecting the swallowing of a toothpick.

Abdomen, Acute↗

[Lipoma of the colon as an unusual cause of recurring partial intestinal occlusion. Clinical case and review of the literature].

A case of a symptomatic colonic lipoma causing recurrent abdominal pain and intestinal obstruction, not treated is reported. Lipomas are the most common mesenchymal benign tumors that can be found in the colon and are second as frequence only to the adenomatous polyps. In 65% of cases the lipomas are located in the large bowel and represent the most common cause of intestinal intussusception in the adult. Lipomas are most frequent in the right colon (40%-68%) an opposite distribution in comparison with adenocarcinomas and adenomatous polyps. When their diameter is more than 3 cm, lipomas become symtomatic. In lipomas less then 2 cm in diameter it is possible an endoscopic removal while for bigger sizes the surgical laparoscopic approach is recommended.

Aged↗

[Bilateral inguinal hernia. Which treatment?].

The authors present a series of 70 bilateral inguinal hernias selected from a total of 641 inguinal hernias operated from May 1994 to November 1996 using alloplastic surgery. They discuss the most appropriate methods of access for treating this pathology in a single operation, and propose inguinal access as the most preferable method owing to its easy execution and apparently greater safety. Laparoscopic techniques should be reserved for special cases such as pluri-recidivating hernias.

Adult↗

[Neuromuscular assessment of the elderly worker: the European NEW project].

Neuromuscular problems reduce working ability of aging workers, and increase cases of work loss and accidents. For this reason, elderly people throughout Europe are forced into early retirement, and fail to be self-supporting. There is a need to identify and monitor work related neuromuscular disorders in order to reduce their consequences by monitoring the most vulnerable individuals, identify the determinants of neuromuscular aging related to occupational conditions, prevent pathologies and their evolution. Preliminary results show the possibility of identification of neuromuscular problems through non invasive techniques, some of which, recently developed within the SENIAM and PROCID Concerted Actions, can provide quantitative indices of neuromuscular performance. Substantial field tests and training initiatives are required to demonstrate if these techniques can be used outside the research labs, if there may be a European market in the fields of ergonomics and occupational health, and if they can be routinely used with standardized methodology to monitor the relationship between occupational and neuromuscular system conditions in the working environment. The objective of the European Project Neuromuscular assessment in the Elderly Worker (NEW) is to answer these questions.

Aged↗

[Volvulus of the sigmoid colon].

Sigmoid colon is the most frequent side for a volvulus. We present four cases of sigmoid volvulus admitted to our department during the period July 1994-December 1995. Intestinal volvulus, despite its benignity, has a quite high morbidity and mortality. Important factors such as the patient's features and frequent late diagnosis can influence the complicated outcome of the disease. Plane X-ray of the abdomen is helpful while barium enema can be therapeutical because of the pressure of the inflated air. Sigmoid resection is the most effective treatment for the disease.

Aged↗