Impaired motor function is a prominent characteristic of aging. Inflammatory processes and oxidative stress from advanced glycation end-products are related to impaired motor function and could plausibly be a contributing factor to the pathogenesis of paratonia, a specific motor disorder in people with dementia. Severe paratonia results in a substantial increase of a caretaker's burden and a decrease in the quality of life. The pathogenesis of paratonia is not well understood, and no effective interventions are available to combat it. Intensive glycaemic control, reducing oxidative stress, possibly combined with a low AGE diet and AGE targeting medication may be the key method for preventing advanced glycation end-product accumulation and reducing the inflammatory burden as well as possibly postponing or preventing paratonia.
BACKGROUND AND PURPOSE: The MyotonPRO is a portable device that measures muscle tone and biomechanical muscle properties objectively. MyotonPRO has already proven to be effective in measuring muscle properties in healthy and diseased populations. However, to the best of our knowledge, it has never been tested in individuals suffering from paratonia, a form of hypertonia frequently accompanying dementia. The aims of the present study were to (1) compare muscle tone, elasticity, and stiffness between 3 different subpopulations of young and old healthy adults and individuals with paratonia, and (2) investigate the intra- and interrater reproducibility of MyotonPRO measurements of the biceps brachii (BB) muscle in each subpopulation.METHODS: MyotonPRO measurements of muscle tone, elasticity, and dynamic stiffness were carried out by 2 investigators on 2 different days over the BB muscles of 54 participants (18 healthy young adults, 20 healthy older adults, and 16 older individuals with paratonia). Muscle properties were compared between subpopulations using ANOVA/Welch and post hoc tests. Reliability (intraclass correlation coefficient) and agreement parameters (standard error of measurement and the minimal detectable change) were calculated.RESULTS: Statistically significant differences between subpopulations were found in all parameters, except for stiffness between healthy elderly and individuals with paratonia. In the healthy subpopulations, (a) intrarater reliability was very high and intrarater agreement was good between 2 consecutive series, (b) between days intrarater reliability was low to high and intrarater agreement was variable, (c) interrater reliability was high to very high and interrater agreement was good. In individuals with paratonia, (a) intrarater reliability was moderate to high and agreement was variable between series, (b) between days intrarater reliability was poor to moderate and agreement was poor, (c) interrater reliability ranged from low to high with poor agreement.CONCLUSIONS: MyotonPRO measurements of the BB muscle showed good reproducibility in both healthy subpopulations, particularly for measurements performed within the same day. In individuals with paratonia, reliability and agreement were substantially lower. MyotonPRO can be used in clinical assessment and research. However, in individuals with paratonia, careful interpretation of results is required. Research in a larger sample of persons with paratonia at different stages of disease severity is recommended.
BACKGROUND AND PURPOSE: Paratonia is a motor problem that develops during the course of dementia. Definitions of paratonia used in the literature differ considerably, which has clinical implications and may lead to an undesirable heterogeneity in study populations. For this reason, we initiated a Delphi procedure with known experts in the field to establish an operational consensus definition of paratonia.METHODS: The Delphi procedure involved an anonymous and multistage approach presented as a questionnaire, with each stage building on the results of the previous one in order to reach consensus on the definition of paratonia.RESULTS: Eight of 17 experts agreed to participate in the study. After 4 rounds, the participants reached consensus on the following definition: paratonia is a form of hypertonia with an involuntary variable resistance during passive movement. The nature of paratonia may change with progression of dementia (eg, from active assistance (aka Mitgehen) to active resistance). The degree of resistance depends on the speed of movement (eg, slow > low resistance, fast > high resistance). The degree of paratonia is proportional to the amount of force applied and increases with progression of dementia. The resistance to passive movement is in any direction and there is no clasp-knife phenomenon.CONCLUSION: The Delphi procedure resulted in a comprehensive, operational definition of paratonia. Future research should focus on the reliability and validity of this definition.
