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Sarcopenia and frailty are common geriatric syndromes and are associated with adverse health outcome and impaired health-related quality of life. Co-occurrences of these two syndromes with age-related neurological diseases are potentially high but not well investigated. Moreover, it is not well understood how these syndromes interact with neurological diseases, such as Parkinson's disease, Alzheimer's disease and stroke. This article introduces the currently most accepted concepts of sarcopenia and frailty, discusses the potential relevance of the syndromes for geriatric patients and presents examples of studies that investigated potential interactions between these geriatric and neurological syndromes and conditions. First results indicate that (i) the co-occurrence of these geriatric syndromes and age-related neurological diseases is high, (ii) sarcopenia and frailty can influence the clinical state of neurological diseases to a relevant extent and (iii) at least some common causes and pathophysiological processes confer the geriatric and neurological conditions. In conclusion, profound knowledge about the interaction of sarcopenia, frailty and age-associated neurological conditions is currently not available. Such knowledge would have an enormous potential for improved therapy of these neurological conditions. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: The cause of sarcopenia is still not fully understood. A multifactorial aetiology is discussed. Neurodegenerative aspects in the genesis of sarcopenia, such as loss of motoneurons, have not yet been explored to a sufficient extent. Method: The Motor Unit Number Index (MUNIX) is a method for assessing the number and size (Motor Unit Size Index — MUSIX) of Motor Units (MUs) using the Compound Muscle Action Potential (CMAP) and the Surface electromyographic Interference Pattern (SIP). This method was used to study the hypothenar muscle in the right hand of 27 sarcopenic patients. Results: The mean MUNIX (111±51) of all investigated sarcopenic patients lies between the mean MUNIX of healthy persons and the mean MUNIX of ALS patients. 25% of sarcopenic patients exhibit pathologic values for both MUNIX (<80) and MUSIX (>100μV). A strong correlation (r=0.75, p<0.001) between MUSIX and the reciprocal value of MUNIX was identified. Conclusion: It was demonstrated for the first time by applying the MUNIX technique that loss of motoneurons plays a pathogenic role in the onset of sarcopenia. This was shown in 25% of sarcopenic participants who exhibited pathologic values for both MUNIX and MUSIX. Nerve sprouting seems to be an important mechanism of compensation for loss of motoneurons, reflected by the strong correlation between MUNIX and MUSIX. Use of MUNIX leads to the identification of a distinct subgroup of sarcopenic patients, which might have a major impact on future diagnostic and therapeutic concepts. [Copyright &y& Elsevier]

Abstract: Introduction: Sarcopenia is considered to be an enormous burden for both the individuals affected and for society at large. A multifactorial aetiology of this geriatric syndrome has been discussed. Amongst other pathomechanisms, the degeneration of the neuromuscular junction (NMJ) may be of major relevance. The intact balance between the pro-synaptic agent agrin and the anti-synaptic agent neurotrypsin ensures a structurally and functionally intact NMJ. Excessive cleavage of the native motoneuron-derived agrin by neurotrypsin into a C-terminal Agrin Fragment (CAF) leads to functional disintegration at the NMJ and may consecutively cause sarcopenia. The present study evaluates the hypothesis that CAF serum concentration is a potential marker for the loss of appendicular lean mass in older adults. It also explores how CAF concentration is influenced by vitamin D supplementation and physical exercise. Method: Serum was taken from 69 (47 female) prefrail community-dwelling older adults participating in a training intervention study to measure the CAF concentration using the Western blot technique. All participants were supplemented orally with vitamin D3 before the training intervention period commenced. Appendicular lean mass (aLM) was evaluated by dual energy X-ray absorptiometry. Multiple linear regression models were used to identify factors significantly associated with CAF concentration. Results: Appendicular lean mass, age and sex were identified as significant explanatory factors for CAF concentration. Gait speed and hand grip strength were not associated with CAF concentration. Male participants showed a strong correlation (r=−0.524) between CAF serum concentration and aLM, whereas this was not the case (r=−0.219) in females. Vitamin D supplementation and physical exercise were significantly associated with a reduction in CAF concentration, especially in participants with initially high CAF concentrations. Conclusions: C-terminal Agrin Fragment could be a potential marker for identifying sarcopenia in a subgroup of affected individuals in the future. The decline of muscle mass seems to be a CAF-associated process in males, whereas the situation in females may be more complex and multifactorial. CAF concentration is reduced by vitamin D supplementation and physical exercise and therefore suggests a potentially positive effect on NMJs. Further prospective studies of sarcopenic patients in addition to muscle biopsy and electromyographical investigations are planned to verify the external validity of the CAF concept. [Copyright &y& Elsevier]

Background: Among current operational definitions of frailty, the criteria proposed by Fried and colleagues have attracted great scientific interest. However, these criteria have usually been applied in epidemiological and only rarely in interventional studies. Objective: The present paper aims at testing the applicability of the Fried frailty criteria in the context of the recruitment process of a randomized controlled trial in prefrail older persons, and it discusses the respective scientific literature. Methods: Recruitment was promoted by newspaper articles as well as by targeted mail to customers of a local health insurance company and to recently treated patients of a geriatric day clinic. Furthermore, presentations were given in assisted living facilities. Potential candidates were screened for prefrailty, i.e. to see whether they met 1 or 2 of the Fried criteria (weight loss, handgrip strength, gait speed, exhaustion, physical activity). Results: A total of 298 people were screened. Among them 181 were not frail, 116 were prefrail and 1 was diagnosed as frail. The most prevalent criterion was exhaustion (24% of those screened). The second most prevalent criterion was low handgrip strength (20%). Low gait speed (8%), low physical activity (2%) and weight loss (2%) had a lower prevalence. According to the Geriatric Depression Scale, 14% of those who met the criterion 'exhaustion' were depressed. With regard to the Minnesota Leisure Time Physical Activity Questionnaire, used for the evaluation of 'physical activity', only 3 activities among the 18 selected by Fried were applicable to our cohort. Conclusions: Under the study conditions, good applicability of the Fried criteria was observed. Nevertheless, further refinement may be expedient in several criteria, especially exhaustion and physical activity, to enhance clinical usefulness. It may be helpful to adapt the cutoffs when applying the criteria to a European population. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]