RESUMEN
Aim Satisfactory short-term outcomes of transobturator tapes (TOTs) are recognized, yet a lack of long-term data exists. We investigated long-term patient-reported outcomes of TOTs. Methods A retrospective review was performed of 100 female patients post TOT insertion by a single surgeon (2005-2010). Results and postoperative complications were identified. At long-term follow-up, patients completed ICIQ-Short Form, PGI-S and PGI-I questionnaires. Results Mean age was 51.7 years (33-75), mean follow-up 9.4 years (7.25 - 12.75). Clinically, 68/100(68%) had mixed and 32/100(32%) pure stress urinary incontinence (SUI). Short-term cure/significant improvement in SUI was seen in 98/100(98%). Grade >2 Clavien-Dindo complications occurred in 10/100(10%) within 6 months of surgery. Long-term questionnaire response rate was 76/100(76%). 62/76 (81.57%) described current urinary condition as "much" or "very much" "better." No new complications emerged at long-term follow-up. Conclusion TOTs demonstrate high success rates in treatment of SUI, with no late-onset complications identified in our study. Recent concerns surrounding use of polypropylene tapes make reporting of long-term outcomes both desirable and necessary.
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Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Cabestrillo Suburetral/efectos adversos , Incontinencia Urinaria de Esfuerzo/cirugía , Femenino , Estudios de Seguimiento , Humanos , Medición de Resultados Informados por el Paciente , Polipropilenos , Estudios Retrospectivos , Encuestas y Cuestionarios , Factores de Tiempo , Resultado del TratamientoRESUMEN
OBJECTIVES: This study evaluated the benefit of physically-active lessons for learning maths multiplication-tables. The impact of the intervention on general numeracy, physical activity (PA), aerobic fitness, body mass index (BMI) and school-day moderate to vigorous PA (MVPA) was also assessed. DESIGN: Randomised controlled cross-over trial. METHOD: Year 3 students (n=172, mean age 8.4±0.3 years, 48% male) were recruited from 10 classes across two urban primary schools. Participants were randomly assigned to a seated classroom (Classroom) group or physically-active lessons in the playground (Playground) and crossed over to the alternative condition in the subsequent school term. The 6-week intervention comprised 3×30min sessions/week. Multiplication-tables (teacher-designed test) and general maths (standardised test) were assessed pre- and post-intervention. Aerobic fitness was assessed via the shuttle-run. Pre- to post-intervention change scores were compared for analysis and effect sizes (ES) calculated. Total PA and MVPA were assessed with accelerometers in a subset of participants. RESULTS: Multiplication scores improved significantly more in Playground than Classroom groups (ES=0.23; p=0.045), while no significant differences were observed in general numeracy (ES=0.05; p=0.66). Total PA and MVPA were substantially higher during Playground than Classroom lessons (ES: total PA=7.4, MVPA=6.5; p<0.001) but there were no differences in PA/MVPA between the groups throughout the rest of the school day. Aerobic fitness improved more in Playground than Classroom groups (ES=0.3; p<0.001) while the change in BMI was not different between groups (p=0.39). CONCLUSIONS: Physically-active lessons may benefit the learning of maths multiplication-tables while favourably contributing to school-day PA/MVPA.
Asunto(s)
Ejercicio Físico , Aprendizaje , Matemática/educación , Modelos Educacionales , Actigrafía , Índice de Masa Corporal , Niño , Estudios Cruzados , Femenino , Humanos , Masculino , Instituciones AcadémicasRESUMEN
The authors investigated metabolic and attentional energy costs as participants (N = 6) practiced in-phase, antiphase, and 90 degrees -phase cycling (order counterbalanced) on independent bicycle ergometers, with resistance (40 W/ergometer) and frequency (40 rpm) held constant. Coordination stabilized and became more accurate for all 3 cycling modes, as shown by measures of relative phase, but that collective variable could not account for other relevant attributes of the multifaceted motor behavior observed across the 3 coordination modes. In-phase and antiphase cycling were similar in stability and accuracy, but antiphase had the lowest metabolic and attentional energy costs. Because both homologous muscle action and perceptually symmetrical oscillations coincided in the in-phase mode, the absence of predominance of the inphase pattern showed that neither of those musculoskeletal and perceptual factors exclusively determined the strongest attractor of the coordination dynamics. Both metabolic and attentional costs declined with practice, consistent with the hypothesis that adaptive motor behavior is guided by sensory information concerning the energy demands of the task. Attentional cost was influenced not only by the information-processing demands of kinematic stability but also by the metabolic energy demands. Metabolic energy cost appeared to be the crucial determinant of the preferred solution for this coordination task.
Asunto(s)
Atención/fisiología , Metabolismo Energético/fisiología , Ejercicio Físico/fisiología , Cinestesia/fisiología , Desempeño Psicomotor/fisiología , Adaptación Fisiológica , Adulto , Fenómenos Biomecánicos , Prueba de Esfuerzo , Humanos , Masculino , Contracción Muscular/fisiología , Valores de Referencia , Estadísticas no ParamétricasRESUMEN
Kinematic (relative phase error), metabolic (oxygen consumption, heart rate) and attentional (baseline and cycling reaction times) variables were measured while participants practised a high energy-demanding, intrinsically unstable 90 degrees relative phase coordination pattern on independent bicycle ergometers. The variables were found to be strongly inter-correlated, suggesting a link between emerging performance stability with practice and minimal metabolic and attentional cost. The effects of practice of 90 degrees relative phase coordination on the performance of in-phase (0 degrees-phase) and antiphase (180 degrees-phase) coordination were investigated by measuring the relative phase attractor layouts and recording the metabolic and attentional cost of the three coordination patterns before and after practice. The attentional variables did not differ significantly between coordination patterns and did not change with practice. Before practice, the coordination performance was most accurate and stable for in-phase cycling, with antiphase next and 90 degrees-phase the poorest. However, metabolic cost was lower for antiphase than either in-phase or 90 degrees-phase cycling, and the pre-practice attractor layout deviated from that predicted on the basis of dynamic stability as an attractor state, revealing an attraction to antiphase cycling. After practice of 90 degrees-phase cycling, in-phase cycling remained the most accurate and stable, with 90 degrees-phase next and antiphase the poorest, but antiphase retained the lowest metabolic energy cost. The attractor layout had changed, with new attractors formed at the practised 90 degrees-phase pattern and its symmetrical partner of 270 degrees-phase. Considering both the pre- and post-practice results, attractors were formed at either a low metabolic energy cost but less stable (antiphase) pattern or at a more stable but higher metabolic energy cost (90 degrees-phase) pattern, but in neither case at the most stable and accurate (in-phase) pattern. The results suggest that energetic factors affect coordination dynamics and that coordination modes lower in metabolic energy expenditure may compete with dynamically stable modes.
Asunto(s)
Atención , Cognición , Metabolismo Energético/fisiología , Extremidad Inferior/fisiología , Desempeño Psicomotor/fisiología , Extremidad Superior/fisiología , Adulto , Fenómenos Biomecánicos , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Consumo de OxígenoRESUMEN
The aim of this study was to characterise the abnormalities of muscle activation which underlie low dexterity after stroke. A broad definition of dexterity was adopted, where loss of dexterity refers to an inability to coordinate muscle activity in the performance of a motor task (i.e. dexterity was not confined to manual dexterity). EMG of biceps brachii and triceps brachii were monitored from 16 people after stroke and 10 neurologically normal controls as they performed a tracking task requiring coordinated elbow flexion and extension. Weakness could not interfere with performance since the task was designed to require minimal strength. Stroke subjects were assigned to a low (n=10) or high (n=6) dexterity group based on their performance. Spatiotemporal aspects of biceps and triceps EMG were analysed. Low dexterity performance after stroke was characterised by excessive biceps muscle activation (P=0.002) and decreased coupling of muscle activation to target motion (P=0.002). In this study, we could rule out weakness, slowness of muscle activation, excessive co-contraction and spasticity as causes of these abnormalities. Therefore, the loss of dexterity after stroke can be seen as a specific negative impairment which can exist independently of other motor impairments and reflects a loss of skill in generating spatial and temporal muscle activation patterns which conform with environmental demands.
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Destreza Motora , Músculo Esquelético/fisiopatología , Accidente Cerebrovascular/fisiopatología , Anciano , Anciano de 80 o más Años , Brazo/inervación , Electromiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Contracción MuscularRESUMEN
A simple model of the joint between the leg and the rearfoot is that of two hinges each with one degree of freedom. The superior hinge at the talocrural joint caters for most of the sagittal plane motion due to its mediolateral orientation. Motion in the transverse and coronal planes is largely taken up by the subtalar joint which has an inclination of 42 degrees to the transverse plane and deviates 23 degrees to the medial side. It could be expected from the orientation of this joint that rearfoot motion in the coronal plane (inversion/eversion) would be tightly coupled to motion in the transverse plane (adduction/abduction). A simple, non-viscous mechanical hinge joint would produce an in-phase, fixed gain relationship between inversion/eversion and adduction/abduction. This relation could be adequately quantified by Pearson's product moment correlation (r(P)). In contrast, muscular control of the joint, which introduces visco-elastic elements and time-delayed control lines and feedback loops, could be characterised by more complex phase and gain relations among the frequency components of the signals. These relations can be characterised by a transfer function relation (gain and phase angle) computed using a dynamic analysis. In the present study, both Pearson's correlation and linear systems analysis were employed. For 43 normal adults, five trials of one walking stride (stance and swing phases) were videographed at 30 Hz with three markers placed on each of the leg and rearfoot. Using inversion/eversion as the input and adduction/abduction as the output, the proportion of the total variance accounted for by a dynamic relation was measured by the coherence square function, which is analogous to the correlation squared (r(P)(2)). The mean r(P)(2) was 0.26, whereas the mean overall coherence was 0.62, thus accounting for more than twice the variance. This result suggests that while there may be a degree of simple mechanical coupling between inversion/eversion and adduction/abduction during walking, the major control is via muscular and/or visco-elastic passive elements.
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Articulación del Tobillo/fisiología , Rango del Movimiento Articular/fisiología , Caminata/fisiología , Adulto , Fenómenos Biomecánicos , Retroalimentación/fisiología , Femenino , Humanos , Masculino , Soporte de Peso/fisiologíaRESUMEN
One defining characteristic of skilled motor performance is the ability to complete the task with minimum energy expenditure. This experiment was designed to examine practice effects on coordination and control, metabolic energy expenditure, and muscle activation. Participants rowed an ergometer at 100 W for ten 16-min sessions. Oxygen consumption and perceived exertion (central and peripheral) declined significantly with practice and movement economy improved (reliably) by 9%. There was an associated but non-significant reduction in heart rate. Stroke rate decreased significantly. Peak forces applied to the ergometer handle were significantly less variable following practice and increased stability of the post-practice movement pattern was also revealed in more tightly clustered plots of hip velocity against horizontal displacement. Over practice trials muscle activation decreased, as revealed in integrated EMG data from the vastus lateralis and biceps brachii, and coherence analysis revealed the muscle activation patterns became more tightly coordinated. The results showed that practice reduced the metabolic energy cost of performance and practice-related refinements to coordination and control were also associated with significant reductions in muscle activation.
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Metabolismo Energético/fisiología , Lateralidad Funcional/fisiología , Contracción Isométrica/fisiología , Desempeño Psicomotor/fisiología , Adolescente , Adulto , Fenómenos Biomecánicos , Electromiografía , Prueba de Esfuerzo , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Destreza Motora/fisiología , Músculo Esquelético/fisiología , Oxígeno/fisiología , Práctica PsicológicaRESUMEN
It is a general assumption that, in able-bodied persons, tonic stretch reflex (TSR) activity is not elicited during stretching of relaxed muscles and that the presence of TSR activity following brain damage is, therefore, indicative of spasticity. However, a variety of studies have reported age-related changes in reflex activity, raising the question of whether this assumption is justified in older subjects. The aim of this study was to determine if TSRs were activated in the relaxed elbow flexors of able-bodied people in an age-group at risk of stroke. Electromyographic (EMG) activity was recorded in 30 able-bodied subjects aged 46 to 78 years when their relaxed elbow flexors were subjected to ramp and sinusoidal stretches of different amplitudes and velocities. It was found that these subjects did not exhibit TSR activity under these conditions. Therefore, the practice of measuring TSR activity as a means of quantifying spasticity in stroke patients appears justified.
Asunto(s)
Envejecimiento/fisiología , Electromiografía , Contracción Isométrica/fisiología , Reflejo de Estiramiento/fisiología , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Procesamiento de Señales Asistido por ComputadorRESUMEN
OBJECTIVES: To estimate the intakes of cereal and dairy products and their contribution to nutrient intakes in men and women from the Republic of Ireland with a view to formulating food-based dietary guidelines. DESIGN: The North/South Ireland Food Consumption Survey established a database of habitual food and drink consumption using a 7-day food diary. From this database all cereal and dairy products from recipes and identifiable sources were identified and a new database was generated from which analysis of the role of cereal and dairy products in the diet was carried out. RESULTS: Almost 100% of the population consumed cereal and dairy products over the course of the survey week. In general, men consumed significantly more cereal and dairy products than did women (P<0.05). Cereal products made an important contribution to the mean daily intakes of energy (26%), protein (21%), fat (13%), carbohydrate (41%), fibre (45%), iron (43%) and folate (27%). Dairy products also contributed largely to the mean daily intakes of energy (11%), protein (14%), fat (17%), calcium (48%), phosphorus (24%) and vitamin A (27%). Analysis of nutrient intakes across tertiles of cereal and dairy consumption showed that high consumers of wholemeal bread, breakfast cereals, reduced-fat milk and yoghurt had lower fat and higher carbohydrate, fibre and micronutrient intakes than low consumers of these foods. CONCLUSIONS: Findings from the present study could be used to develop effective health strategies to implement changes in cereal and dairy consumption that could alter fat, fibre and micronutrient intakes in the diet.
Asunto(s)
Productos Lácteos , Grano Comestible , Conducta Alimentaria , Micronutrientes , Política Nutricional , Adulto , Factores de Edad , Análisis de Varianza , Registros de Dieta , Grasas de la Dieta/análisis , Fibras de la Dieta/análisis , Femenino , Humanos , Irlanda , Masculino , Persona de Mediana Edad , Encuestas Nutricionales , Factores Sexuales , Estadísticas no ParamétricasRESUMEN
OBJECTIVES: To examine the temporal pattern of the number of eating occasions that occurred at home, at work and outside the home, and to examine the contribution of fat to energy and the contribution of 26 food groups to fat at home and outside the home. DESIGN AND SETTING: Food intake data were collected using a 7-day food diary from a random sample of 18-64-year-old adults from the Republic of Ireland (n=958). Respondents recorded the day, time and location of every eating occasion. RESULTS: The number of eating occasions was constant across the days of the week for meals consumed at home, whereas the number of eating occasions increased at weekends for meals outside the home. The contribution of fat to energy approximated the 35% recommendation at home from Monday to Friday, but increased above this on Saturday and Sunday. The contribution of fat to energy outside the home was always above the recommendation. The food groups that contributed most to fat were similar at home and outside the home. These included butter and full-fat spreads, fresh meat, meat products, meat dishes, biscuits, cakes and pastries, whole milk, and chips and processed potatoes. CONCLUSION: The contribution of fat to energy was above the recommendations when eating outside the home, regardless of day of the week. A number of food groups have been identified that contributed most to fat intake outside the home and these might be targeted in developing public health nutrition strategies to reduce fat intake.
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Grasas de la Dieta/administración & dosificación , Ingestión de Energía , Conducta Alimentaria , Política Nutricional , Adolescente , Adulto , Análisis de Varianza , Registros de Dieta , Grasas de la Dieta/metabolismo , Femenino , Humanos , Irlanda , Masculino , Persona de Mediana Edad , RestaurantesRESUMEN
OBJECTIVES: To examine the contribution of the food service sector to the nutrient quality of the Irish diet, and to compare intakes at home, work and outside the home ('out') and within the subgroups of the out location (pub, deli, takeaway). DESIGN AND SETTING: Random sample of adults from the Republic of Ireland. Food intake data were collected using a 7-day food diary. Respondents recorded the location of every eating occasion determined by where the food was prepared rather than consumed. RESULTS: Intakes of energy, protein, fat and carbohydrate were significantly greater at home than at work or out (P<0.05). The intake of alcohol was significantly (P<0.001) greater out than at home or work. The percentage contribution of fat to energy was above the recommendations (33% of total energy and 35% of food energy) for both men and women at all locations, with the exception of the contribution of fat to total energy for men at the out location. Within the subgroups of the out location, the contribution of alcohol to total energy was greatest in pubs and the contribution of fat to both total and food energy was greatest in takeaways. Intakes of fibre and most micronutrients per 10 MJ of food energy were greater (P<0.05) at home than at work or out. CONCLUSION: Foods eaten outside the home contribute a disproportionately high level of fat intake and should be targeted in public health nutrition strategies.
Asunto(s)
Ingestión de Energía , Política Nutricional , Adolescente , Adulto , Factores de Edad , Análisis de Varianza , Registros de Dieta , Carbohidratos de la Dieta/administración & dosificación , Carbohidratos de la Dieta/metabolismo , Grasas de la Dieta/administración & dosificación , Grasas de la Dieta/metabolismo , Fibras de la Dieta/administración & dosificación , Proteínas en la Dieta/administración & dosificación , Femenino , Humanos , Irlanda , Masculino , Persona de Mediana Edad , RestaurantesRESUMEN
OBJECTIVES: To analyse the temporal distribution of the intake of cereal and dairy products in the Republic of Ireland. DESIGN: The North/South Ireland Food Consumption Survey established a database of habitual food and drink consumption using a 7-day food diary. The database also recorded the time and day of food consumption. Mean intakes of cereal and dairy products were calculated for time of the day and day of the week. RESULTS: At the weekend, the percentage of consumers decreased for nearly all cereal and dairy products. White bread, total cereals, full-fat milk and total dairy intakes were significantly lower at the weekend (P<0.01) compared with weekdays. Intakes of cereal and dairy products over time of the day showed clear mealtime or snacking patterns when the number of consumers was controlled for. White bread, wholemeal bread, total cereals, full-fat milk, reduced-fat milk and total dairy intakes showed mealtime peaks for morning, afternoon and evening. When examined by tertile of intake, tertile of percentage energy from fat and tertile of fibre intake, intakes of cereal and dairy products over time of the day and day of the week were similar to trends described above, regardless of the tertile. CONCLUSIONS: Temporal analysis of the intakes of cereal and dairy products did not reveal any unusual trends in this population. However, the significant methodological issues raised in this paper will be of benefit to other aspects of research in this area.
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Productos Lácteos , Registros de Dieta , Grano Comestible , Conducta Alimentaria , Política Nutricional , Adolescente , Adulto , Análisis de Varianza , Grasas de la Dieta/análisis , Fibras de la Dieta/análisis , Femenino , Humanos , Irlanda , Masculino , Persona de Mediana Edad , Factores Sexuales , Factores de TiempoRESUMEN
BACKGROUND: Spasticity is defined/assessed in resting limbs, where increased stretch reflex activity and mechanical joint resistance are evident. Treatment with antispastic agents assumes that these features contribute to the movement disorder, although it is unclear whether they persist during voluntary contraction. OBJECTIVES: To compare reflex amplitude and joint resistance in spastic and normal limbs over an equivalent range of background contraction. METHODS: Thirteen normal and eight hemiparetic subjects with mild/moderate spasticity and without significant contracture were studied. Reflex and passive joint resistance were compared at rest and during six small increments of biceps voluntary contraction, up to 15% of normal maximum. A novel approach was used to match contraction levels between groups. RESULTS: Reflex amplitude and joint mechanical resistance were linearly related to contraction in both groups. The slopes of these relations were not above normal in the spastic subjects on linear regression. Thus, reflex amplitude and joint resistance were not different between groups over a comparable range of contraction levels. Spastic subjects exhibited a smaller range of reflex modulation than normals because of decreased maximal contraction levels (weakness) and significant increases of resting contraction levels. CONCLUSIONS: Spasticity was most evident at rest because subjects could not reduce background contraction to normal. When background contractions were matched to normal levels, no evidence of exaggerated reflex activity or mechanical resistance was found. Instead, reduced capacity to modulate reflex activity dynamically over the normal range may contribute to the movement disorder. This finding does not support the routine use of antispastic agents to treat the movement disorder.
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Hemiplejía/fisiopatología , Contracción Isométrica/fisiología , Espasticidad Muscular/fisiopatología , Reflejo de Estiramiento/fisiología , Adulto , Anciano , Estudios de Casos y Controles , Articulación del Codo/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/fisiopatología , Descanso/fisiología , TorqueRESUMEN
Mechanisms of spasticity and possible therapeutic interventions continue to dominate research into motor disorders following cerebral lesions. However, the accumulated evidence suggests that this focus on spasticity may be out of step with its effects. In contrast, hypertonia remains an important problem. Further investigation into its link with muscle contracture is required and it needs to be clearly distinguished from reflex hyperexcitability in patients with spasticity.
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Contractura/fisiopatología , Enfermedad de la Neurona Motora/fisiopatología , Hipertonía Muscular/fisiopatología , Espasticidad Muscular/fisiopatología , Reflejo Anormal/fisiología , Daño Encefálico Crónico/complicaciones , Daño Encefálico Crónico/fisiopatología , Daño Encefálico Crónico/terapia , Contractura/terapia , Humanos , Enfermedad de la Neurona Motora/terapia , Neuronas Motoras/fisiología , Hipertonía Muscular/terapia , Espasticidad Muscular/terapia , Músculo Esquelético/inervación , PronósticoRESUMEN
Athetoid dysarthria is thought to result from involuntary movements which are variable and irregular in nature. In this study, electromyographic (EMG) activity recorded from six speech muscles was quantified during repetitions of a test sentence by normal and athetoid adult subjects. In the athetoid subjects the articulation of the test sentence was disrupted intermittently by involuntary activity which usually occurred in the time intervals between the syllables in the test sentence, rather than during articulation of the syllables themselves. The EMG activity associated with each syllable in the test sentence was partitioned into reproducible and variable components. The ratio of the reproducible component to the variable component--the signal-to-noise ratio--did not differ significantly between the two subject groups. In the athetoid subjects, however, the reproducible component of the EMG activity was grossly abnormal. We concluded that this abnormal voluntary activity, rather than variable involuntary activity, was the primary cause of athetoid dysarthria.
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Atetosis/fisiopatología , Parálisis Cerebral/fisiopatología , Disartria/fisiopatología , Músculos Faciales/fisiología , Trastornos del Habla/fisiopatología , Habla/fisiología , Adulto , Atetosis/etiología , Parálisis Cerebral/complicaciones , Disartria/etiología , Electromiografía , Humanos , RuidoRESUMEN
Time domain and frequency domain analyses were performed on smoothed and averaged electromyographic (IEMG) activity recorded intramuscularly from 6 muscles of the lips, tongue and jaw during speech in normal and athetoid cerebral palsy subjects. The speech IEMG waveforms in both groups were composed of slowly changing tonic activity merging with more rapidly changing phasic bursts. Significant increases both in the durations and average levels of IEMG activity in the athetoid subjects resulted in a 5- to 30-fold increase in the speech muscle energy expended by these subjects. The peak-to-peak amplitudes of the IEMG activity were significantly increased in the athetoid subjects, commensurate with their increased average levels, thus demonstrating that they could vary their muscle contraction levels over a wide range. The velocities (rates of change) of muscle IEMG activity did not differ significantly between the two groups. The velocity of the IEMG activity increased linearly with its amplitude in both subject groups, but the durations of the IEMG bursts nevertheless were highly variable. The slope of the velocity-amplitude relation in the athetoid subjects was less than half that in the normal subjects, suggesting that the frequency bandwidth of muscle activity was reduced in the athetoid subjects, despite a normal range of IEMG velocities. The frequency analysis confirmed this suggestion. The upper limit of the average frequency spectrum of voluntary muscle activity for speech was 7 Hz in the normal subjects, whereas this limit was 4 Hz in the athetoid subjects. In the normal subjects each muscle had a different frequency spectrum, whereas the spectra for the 6 muscles were remarkably uniform in the athetoid subjects, implying an abnormality in the functional organization of their muscles. The findings of this study showed clearly that the temporospatial patterns of voluntary muscle activity in the athetoid subjects were grossly abnormal. Since this voluntary activity was reproducible across multiple repetitions of the same speech sample, the dysarthria in these speakers may be attributed to abnormal control of voluntary activity, not to involuntary movement. The results support the view that the primary disability in cerebral palsy is a disruption of the physiological mechanisms which subserve the acquisition of motor skills.
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Atetosis/fisiopatología , Disartria/fisiopatología , Boca/fisiopatología , Músculos/fisiopatología , Trastornos del Habla/fisiopatología , Adulto , Atetosis/complicaciones , Parálisis Cerebral/complicaciones , Parálisis Cerebral/fisiopatología , Disartria/etiología , Electromiografía/métodos , Humanos , Maxilares , Labio/fisiopatología , Lengua/fisiopatologíaRESUMEN
When studying muscle stretch reflexes with tonic stimuli or making a clinical assessment of muscle tone, it is imperative that the subject does not track the stretch stimulus either consciously or unconsciously. Such tracking contaminates reflex responses with voluntary ones and so invalidates any conclusions reached. Ideally, the stimuli used should be beyond the speed of a person's tracking ability. Both experiments on tonic stretch reflexes and clinical assessment of muscle tone of necessity involve the application of perturbations to the same limb from which a response is to be measured. These perturbations produce different peripheral feedback from the limb, including particularly cutaneous signals but also different Golgi tendon and muscle spindle afference than would occur for similar movements made voluntarily. This combination of peripheral signals resulting from perturbation of a limb is referred to here as perturbational feedback. There is evidence in the literature that subjects can generate voluntary responses to same-limb perturbations within latencies normally accepted for reflexes. Such fast responses might enable faster targets to be tracked voluntarily. In this study the tracking frequency response for the forearm was investigated using sinusoidal and irregular target signals. Perturbations were applied to a manipulandum and the subjects were required to voluntarily track these perturbations under two conditions: (1) where their arm was secured in the manipulandum and therefore they had perturbational feedback of tracking errors and (2) where their tracking arm was not in contact with the manipulandum and they had only visual or kinesthetic feedback of tracking errors. For sinusoidal target inputs, perturbational feedback allowed superior tracking performance. Many subjects could produce good tracking responses at 5 Hz and some as high as 7 Hz. This is a considerably higher frequency than was found when perturbational feedback was not present and greater than has been reported in the literature for all other types of tracking (typically about 2 Hz). In contrast, when irregular signals having power up to 4 Hz were used, perturbational feedback conferred only a marginal advantage on tracking performance. The enhancement of sinusoidal tracking performance by feedback may be due to the fact that cyclic movements can be internally generated by the subject and minimal reference to external cues provided by perturbational feedback can be used to synchronise such self-generated movements with a target. In contrast, this proposed mechanism cannot be used for tracking of irregular targets. Since perturbational feedback did not improve the maximum tracking frequency for irregular targets, there was no evidence for the operation of a shorter latency, same-limb displacement response.
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Nervios Periféricos/fisiología , Desempeño Psicomotor/fisiología , Reflejo de Estiramiento/fisiología , Adulto , Análisis de Varianza , Estimulación Eléctrica , Retroalimentación , Humanos , Masculino , Oscilometría , TorqueRESUMEN
It has become increasingly recognized that the major functional deficits following brain damage are largely due to "negative' features such as weakness and loss of dexterity rather than spasticity. A variety of studies suggest that spasticity is a distinct problem and separate from the loss of dexterity, but that it may be implicated in the formation of muscle contracture and even in the recovery of strength. In order to address these issues, we examined the relationship between spasticity, contracture, strength and dexterity in the affected upper limb following stroke. Spasticity was measured both as increased tonic stretch reflexes and increased resistance to passive stretch (hypertonia). Twenty-four patients were recruited non-selectively from three rehabilitation units within 13 months of their stroke. Few patients exhibited increased tonic reflexes but half were found to have muscle contracture, the earliest at 2 months following stroke. Hypertonia was associated with contracture but not with reflex hyperexcitability. Increased tonic stretch reflexes were observed only in a subgroup of those with contracture and where present could usually be elicited only at the end of muscle range. This findings suggests that instead of spasticity causing contracture, contracture may actually potentiate spasticity in some patients. However, the majority of patients with contracture did not have increased tonic stretch reflexes. In addition, we found no relationship between spasticity and either weakness or loss of dexterity. Therefore, while hypertonia remains an important problem following cerebral lesions, it would appear that the amount of attention directed to reflex hyperexcitability associated with spasticity is out of proportion with its effects. Consequently, hypertonia needs to be clearly distinguished from reflex hyperexcitability in patients with spasticity.
Asunto(s)
Trastornos Cerebrovasculares/fisiopatología , Contracción Muscular/fisiología , Espasticidad Muscular/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Codo/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Subjects with cerebral palsy aged six to 19 years undertook a training programme to reduce spasticity and contracture of the triceps surae muscle using feedback of the gain of the tonic stretch reflex. Stretch reflex gain was significantly reduced (by 50 per cent on average) in all eight test subjects, whereas there was no significant change in control subjects, matched for age and level of spasticity, who had no reflex training. Contracture of the triceps surae muscle was not altered. Since the reduction in spasticity can be expected to slow the recurrence of muscle shortening, it is suggested that for correction of muscle contracture, muscle-lengthening procedures to promote muscle growth should be combined with reflex training to maintain the growth achieved.