Jan-Peter Krenovsky1, Kai Bötzel2, Andres Ceballos-Baumann3, Urban M Fietzek3, Benedikt Schoser4, Walter Maetzler5, Uta Ferrari6, Michael Drey6. 1. Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany, janpeter.krenovsky@med.uni-muenchen.de. 2. Department of Neurology, University Hospital, LMU Munich, Munich, Germany. 3. Schön Klinik München Schwabing, Department of Neurology and Clinical Neurophysiology, Munich, Germany. 4. Friedrich Baur Institute at the Department of Neurology, University Hospital, LMU Munich, Munich, Germany. 5. Department of Neurology, Christian-Albrechts University, Kiel, Germany. 6. Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany.
Abstract
INTRODUCTION: Pathogenesis in a subgroup of sarcopenic patients seems to be based on a reduced number of motor neurons. This study aimed at investigating the overlap between sarcopenia and neurodegeneration, as reflected by a low number of motor neurons in patients with Parkinsonian syndromes (PS). METHODS: The motor unit number index (MUNIX) of the hypothenar muscle was used to assess the number and size (MUSIX) of motor units (MUs) in patients with idiopathic Parkinson disease (iPD, n = 53), patients with atypical Parkinsonian syndrome (aPS, n = 21), and a control group (n = 30). Mean age of participants was 70.3 years and 54.1% were female. Skeletal muscle mass by bioelectrical impedance analysis, hand-grip strength and gait speed were measured. Based on these assessments, sarcopenia was diagnosed according to the criteria of the European Working Group on Sarcopenia in Older People. RESULTS: Sarcopenia criteria were met by 10 patients with PS (13.5%). The study group had significantly lower MUNIX values than the control group (109 [SD ±39.1] vs. 129 [SD ±45.1]; p = 0.020) even after adjustment for age and sex. Three of the 5 sarcopenic iPD patients (75%) had pathological low MUNIX values (<80). DISCUSSION/ CONCLUSION: Sarcopenia is a frequent comorbidity in PS. The pathologically low MUNIX values found in 75% of our sarcopenic iPD patients provides further support for the existence of a neurodegenerative overlap syndrome with a reduced number of MUs potentially leading to sarcopenia. This finding warrants further evaluation.
INTRODUCTION: Pathogenesis in a subgroup of sarcopenic patients seems to be based on a reduced number of motor neurons. This study aimed at investigating the overlap between sarcopenia and neurodegeneration, as reflected by a low number of motor neurons in patients with Parkinsonian syndromes (PS). METHODS: The motor unit number index (MUNIX) of the hypothenar muscle was used to assess the number and size (MUSIX) of motor units (MUs) in patients with idiopathic Parkinson disease (iPD, n = 53), patients with atypical Parkinsonian syndrome (aPS, n = 21), and a control group (n = 30). Mean age of participants was 70.3 years and 54.1% were female. Skeletal muscle mass by bioelectrical impedance analysis, hand-grip strength and gait speed were measured. Based on these assessments, sarcopenia was diagnosed according to the criteria of the European Working Group on Sarcopenia in Older People. RESULTS:Sarcopenia criteria were met by 10 patients with PS (13.5%). The study group had significantly lower MUNIX values than the control group (109 [SD ±39.1] vs. 129 [SD ±45.1]; p = 0.020) even after adjustment for age and sex. Three of the 5 sarcopenic iPDpatients (75%) had pathological low MUNIX values (<80). DISCUSSION/ CONCLUSION:Sarcopenia is a frequent comorbidity in PS. The pathologically low MUNIX values found in 75% of our sarcopenic iPDpatients provides further support for the existence of a neurodegenerative overlap syndrome with a reduced number of MUs potentially leading to sarcopenia. This finding warrants further evaluation.