Sarcopenia, low muscle strength, cognitive functions, and quality of life in parkinsonian syndromes

Parkinsonian syndromes are disabling neurodegenerative diseases resulting in reduced muscle function/performance and sarcopenia, but clinical manifestations could be systemic, including deterioration of cognitive function. As studies have reported an association between muscle dysfunction and cognitive decline yet no information on these syndromes is available, we investigated the relationship between sarcopenia, its components, and cognitive function, fatigue, and quality of life (QoL).

Consecutive patients affected by parkinsonian syndromes were assessed for the presence of sarcopenia using the European Working Group on Sarcopenia in Older People-2 algorithm: low strength (handgrip strength: <27 kg [men]; <16 kg [women]) and low appendicular skeletal muscle index by impedance (<7.0 kg/m² [men]; <6.0 kg/m² [women]). Cognitive function was evaluated using the Montreal Cognitive Assessment, the Mini Mental State Examination and the Frontal Assessment Battery. Fatigue and QoL were assessed using the 16-item Parkinson's Disease Fatigue Scale and the 39-item Parkinson's Disease Questionnaire, respectively.

In total, 314 patients were included: 198 presented with low strength (63.0% probable sarcopenia); 68 (21.7%) of these were diagnosed with sarcopenia. After adjusting for multiple confounders, we observed a significant effect (poorer score) of both low strength only and sarcopenia on Montreal Cognitive Assessment, Mini Mental State Examination, and QoL. Only reduced muscle strength had a relevant impact on the outcomes considered.

Sarcopenia is associated with worse cognitive functions and QoL in patients with parkinsonian syndromes, with muscle dysfunction playing a major role. The prognostic impact of sarcopenia and its components should be addressed in prospective studies.