It is generally accepted that when subjects move voluntarily in response to a reaction signal, the cerebral cortex plays a major role in identifying the sensory stimulus and releasing the instructions to move. Indeed, theoretical models have been put forward in psychophysiological studies to symbolize the steps of such cerebral processing (Gratton et al. 1988). In contrast, startle reactions occur via a subcortical reflex mechanism. Sensory inputs activate the reticular formation and the descending reticulo-spinal tract to the spinal cord (Davis et al. 1982). Because of the differences in the length of the circuits, as well as in the amount of sensory processing, the latencies of the startle reaction are much shorter than those of a voluntary reaction. In muscles of the forearm, a startle reaction occurs at less than 80 ms. In contrast, the voluntary reaction time to a visual 'go' signal is of the order of 150 ms. The reaction time to auditory and somatosensory stimuli is shorter but even then rarely less than 100 ms (Brown et al. 1991a;Thompson et al. 1992;Pascual-Leone et al. 1992). Recently, Valls-Sol e et al. (1995) have shown that reaction times can be considerably reduced if a very loud, startling, sound is given at the same time as the visual 'go' signal. The amount of shortening is much greater than that observed in conventional intersensory facilitation (Nickerson, 1973), and presumably represents a specific startle-related effect. The question is what neural mechanisms are responsible for this Journal of Physiology (1999) 1. The reaction time to a visual stimulus shortens significantly when an unexpected acoustic startle is delivered together with the 'go' signal in healthy human subjects. In this paper we have investigated the physiological mechanisms underlying this effect. If the commands for the startle and the voluntary reaction were superimposed at some level in the CNS, then we would expect to see alterations in the configuration of the voluntary response. Conversely, if the circuit activated by the startling stimulus is somehow involved in the execution of voluntary movements, then reaction time would be sped up but the configuration of the motor programme would be preserved. 2. Fourteen healthy male and female volunteers were instructed to react as fast as possible to a visual 'go' signal by flexing or extending their wrist, or rising onto tiptoe from a standing position. These movements generated consistent and characteristic patterns of EMG activation. In random trials, the 'go' signal was accompanied by a very loud acoustic stimulus. This stimulus was sufficient to produce a startle reflex when given unexpectedly on its own. 3. The startling stimulus almost halved the latency of the voluntary response but did not change the configuration of the EMG pattern in either the arm or the leg. In some subjects the reaction times were shorter than the calculated minimum time for processing of sensory information at the cerebral cortex. Most subjects reported that the very rapid responses were produc...
The aim of the present study was to evaluate the psychometric properties of the Brazilian version of the Nottingham Health Profile (NHP), a generic instrument for quality of life assessment. This NHP was translated to Portuguese, following recommended methodology, and applied to 215 subjects, being 170 community elderly (66.3 ± 8.5 years), 30 chronic stroke survivors (56.4 ± 10.9 years), and 15 parkinsonians (59.6 ± 10.2 years). The data was analysed by Rasch analysis. Out of the 38 items of NHP, only two items (5%) did not fit the statistical model, indicating that the items collaborated to mea- IntroduçãoUm instrumento de avaliação de qualidade de vida não deve se limitar, simplesmente, a medir a presença e a gravidade dos sintomas de uma doença. Deve também ser capaz de mostrar como as manifestações de uma doença ou tratamento são experimentadas pelo indivíduo 1,2,3,4 valorizando aspectos da vida que geralmente não são considerados como "saúde", como, por exemplo, renda familiar, autonomia e trabalho 5 .A utilização desses instrumentos na avaliação da qualidade de vida tem sido reconhecida como uma importante área do conhecimento científico no campo da saúde 2,3,6 . Carr et al. 7 reafirmaram a importância destes instrumentos em inquéritos populacionais ou como identificadores das necessidades de saúde da população, bem como na prática clínica ou em experimentos clínicos controlados. Nestes tipos de estudos, é essencial o uso de medidas de qualidade de vida que sejam válidas, confiá-veis e, sobretudo, sensíveis às mudanças clíni-cas obtidas com o tratamento 2,7 . Em muitos países, devido ao acesso restrito a questioná-rios, além dos gastos em tempo e dinheiro necessários para produzi-los, a adaptação de questionários tem sido vista como uma forma simples de se obter medidas válidas e confiá-veis, visto que um questionário culturalmente adaptado indica que tanto a linguagem, quanTeixeira-Salmela et al. 906Cad. Saúde Pública, Rio de Janeiro, 20(4): 905-914, jul-ago, 2004 to o significado dos itens contidos no instrumento, são consistentes com aqueles do documento original 1,8,9,10 .O Perfil de Saúde de Nottingham (PSN) é um instrumento genérico de avaliação de qualidade de vida, desenvolvido originalmente para avaliar a qualidade de vida em pacientes portadores de doenças crônicas 11,12,13 . Trata-se de um questionário auto-administrado, constituí-do de 38 itens, baseados na classificação de incapacidade descrita pela Organização Mundial da Saúde, com respostas no formato sim/não. Os itens estão organizados em seis categorias que englobam nível de energia, dor, reações emocionais, sono, interação social e habilidades físicas. Cada resposta positiva corresponde a um escore de um (1) e cada resposta negativa corresponde a um escore zero (0), perfazendo uma pontuação máxima de 38. Utilizando uma linguagem de fácil interpretação, o PSN fornece uma medida simples da saúde física, social e emocional do indivíduo 12,14 , sendo considerado clinicamente válido para distinguir pacientes com diferentes nív...
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