Rozprawy doktorskie na temat „Muscle rigidity”

Rigidity is one of the cardinal symptoms in Parkinson's disease, along with Bradykinesia, tremor and postural instability. Rigidity in PD has been understudied, but its pathophysiological basis remains unclear. Various types of neurophysiological and biomechanical approach have been developed in order to investigate the neural control of muscle tone. A common approach is to observe the sensitivity of muscle resistance in response to stretch velocity or displacement [Kamper, Rea, He]. A recent study on elbow flexors in patients with spasticity and rigidity showed a velocity dependent increase in reactive torque in both groups [Lee H, et al). Even though this Study shows a correlation between elbow flexors and velocity, it doesn't discuss the role of elbow extensors. We studied the rigidity response in the elbow of both arms to different speed movements in 12 patients suffering from Parkinson's disease ON or OFF medication. The purpose of this study was to look at both elbow flexion and extension and show that quantitative measures of rigidity and movement disorders in subjects with Parkinson's disease correlate with the currently used clinical evaluations and also find the correlation between velocity and both elbow extension and flexion at the same time. Elbow was flexed and extended by means of a robotic arm,under four different speeds. The resistance to movement was recorded with a torque sensor and EMG of two elbow muscles; Biceps and Triceps; was recorded while the subjects were attempting to relax. The patients were also examined by physicians and their elbow rigidity and muscle tone and Parkinson's disease stage was evaluated and a Universal score in the categories of UPDRS, MMSE, and CAPIT was assigned for each arm of each individual. In the end we will argue that there is a very strong correlation between speed and elbow Extension and Flexion, muscle activity and the rigidity presented in each arm. We will also present the correlation between the robotic torque measurement and the clinical scores given to each subject.

This study focuses on developing a new approach to seated work positions. It was conducted on 67 office workers who use the Video Display Terminal (VDT) as a major function of their working day. Muscle tension was measured by surface electromyography when subjects were asked to adopt four selected working postures. Pain was measured before and after ergonomic intervention on the Nordic scale, which was modified for this study. Performance was measured on timed typing tests. A psychosocial questionnaire was used to determine influences of job demands, and a diagnostic assessment was performed to determine symptoms and pre-existing musculoskeletal conditions. Furniture was used to place subjects in desired positions during the clinical testing sessions and the extended intervention period. The chair seat pan was adjusted to a forward tilt to promote a lordotic curve of the low back, resulting in an erect upper body and upright head position. The desk and keyboard were adjusted to the proper height for each worker. A neutral wrist position was obtained by lowering and tilting the keyboard away from the user. Results revealed muscle tension scores in the upper trapezius and forearm extensors were significantly reduced when the workers were placed with the head in a midline position, with forward-tilting seating and with use of a negative sloping keyboard tray. Subjects reported low pain scores at pretest so no changes were noted after intervention. Loss of control over job elements, lack of job satisfaction, and fear of job loss were related to an increase in muscle tension. Only fear of job loss correlated to increased pain levels. There was no relationship between any of the job demand factors and performance.

Background: Spasticity is a common neurological impairment after injury to the central nervous system, but the neural and biomechanical contributions to it are still poorly understood. Histopathological studies have demonstrated a generalized increase in extracellular connective tissue in spastic muscles, which can decrease its compliance, and reduce the threshold for stimulation of the spindle receptors. Here we propose and provide preliminary evidence for a novel hypothesis for exacerbation of spasticity in an immobilized limb - the hyaluronan hypothesis. We hypothesize that the extracellular connective tissue, which is composed chiefly of hyaluronan, becomes hyper-viscous and stiff in an immobilized limb due to its non-Newtonian properties. Methods: In this case series, we assessed the safety, tolerability, and efficacy of human recombinant hyaluronidase, which hydrolyzes hyaluronan, in combination with saline in restoring tissue compliance. Twenty-one individuals, with moderate-severe upper limb spasticity affecting more than one joint, received multiple intramuscular injections of hyaluronidase-saline. Adverse effects were monitored over 15 weeks. The Modified Ashworth Scale (MAS) assessed reduction in spasticity while active and passive range of motion was assessed using quantitative video analysis of upper limb movement. Findings: 21 participants were included. The procedure was well tolerated. Extensive safety monitoring in all patients revealed no clinically significant adverse events at 15 weeks. Treatment seemed to be effective at reducing spasticity in all twenty-one participants who received the injections (p<0.05 in 16 evaluation over 24 in passive ROM and 17 over 24 in active ROM). The measures of motor function (MAS) showed still improvement at 15 months (p=.000). Interpretations: Subcutaneous administration of hyaluronidase-saline in a multiple sites was fairly safe and well tolerated in adult patients with spasticity; however, these results must be viewed as preliminary until data from blinded, controlled clinical trials are available.<br>Introduzione: La spasticità è un danno neurologico comune conseguente ad una lesione al sistema nervoso centrale, ma i contributi neurali e biomeccanici ad esso correlati sono ancora poco conosciuta. Studi istopatologici hanno dimostrato un aumento generalizzato nel tessuto connettivo extracellulare nei muscoli spastici, che può diminuire la sua funzionalità e ridurre la soglia per la stimolazione dei fusi neuromuscolari. Con questo lavoro proponiamo e forniamo le prove preliminari per una nuova ipotesi per l'esacerbazione della spasticità in un arto immobilizzato: l'ipotesi ialuronato. Si Ipotizza che il tessuto connettivo extracellulare, che è composto principalmente da ialuronato, diventi iper-viscoso e rigido in un arto immobilizzato grazie alle sue proprietà non-Newtoniane. Metodi: In questo case series, è stata valutata la sicurezza, tollerabilità e efficacia della ialuronidasi ricombinante umana, che idrolizza lo ialuronato, in combinazione con una soluzione salina per ripristinare la funzionalità dei tessuti. Ventuno persone fisiche, con moderata-grave spasticità degli arti superiori in più di una articolazione, hanno ricevuto multiple iniezioni intramuscolari di ialuronidasi-salina. Gli effetti avversi sono stati monitorati per 15 settimane. La Modified Ashworth Scale (MAS) ha valutato la riduzione della spasticità mentre la l’escursione articolare di movimento attiva e passiva è stata valutata mediante analisi quantitativa del movimento dell'arto (ROM) superiore tramite video. Risultati: 21 partecipanti sono stati inclusi. La procedura è stata ben tollerata. Il monitoraggio estensivo sulla sicurezza dei pazienti non ha rivelato eventi avversi clinicamente significativi a 15 settimane. Il trattamento è risultato efficace nel ridurre la spasticità in tutti i ventuno partecipanti che hanno ricevuto le iniezioni (p <0.05 di 16 valutazione su 24 nella ROM passivo e 17 su 24 nel ROM attivo). Le misure di funzione motoria (MAS) hanno mostrato un mantenimento del miglioramento a 15 mesi (p = 0,000). Conclusioni: La somministrazione di ialuronidasi-salina in più siti è risultata sicura e ben tollerata in pazienti adulti con spasticità; tuttavia, questi risultati devono essere visti come preliminari fino a quando ulteriori studi clinici controllati in cieco non saranno disponibili.