Multiple sclerosis and sarcopenia: analysis of population-level prevalence and key risk factors from the UK Biobank.

Background: Sarcopenia and presarcopenia are characterized by the age-related deterioration of skeletal muscle mass and/or function and are associated with adverse health outcomes. The relationship between multiple sclerosis (MS) and sarcopenia/presarcopenia are poorly understood.

Objectives: To examine the prevalence of presarcopenia/sarcopenia in people with MS compared to the non-MS population.

Toward therapeutic trials in primary lateral sclerosis.

Primary lateral sclerosis (PLS) is a rare neurodegenerative disorder primarily affecting the upper motor neurons. People living with PLS experience progressive physical and communication disability, which typically evolves slowly over several years. In contrast to amyotrophic lateral sclerosis (ALS), life expectancy is anticipated to be normal.

Variability across versions of the self-administered ALSFRS-R: a review and call for harmonization.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease predominantly affecting motor neurons resulting in substantial, progressive disability. The amyotrophic lateral sclerosis functional rating scale - revised (ALSFRS-R) is commonly used to assess and monitor functional status in patients with ALS. Additionally, it is the current regulatory accepted primary outcome measure documenting functional status in ALS clinical trials.

Concurrent nodular lymphocytic myositis and myasthenia gravis. A case report.

Localized painful nodules associated with focal myositis have been previously documented, either as isolated occurrences or in conjunction with systemic illnesses, such as polymyositis [1-4]. These nodules typically manifest over the course of 2-8 weeks and exhibit histological features consistent with inflammatory myositis. Here we present a unique case of a patient with a history of myasthenia gravis, who experienced exacerbation of myasthenic symptoms, accompanied by the development of palpable, tender nodules on her thighs and proximal weakness.

Acute changes in forearm vascular compliance during transient sympatho-excitation.

The study of vascular regulation often omits important information about the elastic properties of arteries under conditions of pulsatile flow. The purpose of this study was to examine the relationship between muscle sympathetic nerve activity (MSNA), vascular bed compliance, and peripheral blood flow responses in humans. We hypothesized that increases in MSNA would correlate with reductions in vascular compliance, and that changes in compliance would correspond with changes in peripheral blood flow during sympatho-excitation.

Cerebral haemodynamics during arrhythmia in health, ischaemic heart disease and heart failure with reduced ejection fraction, and in a preclinical swine model.

Ventricular arrhythmias are associated with neurological impairment and could represent a source of cerebral hypoperfusion. In the present study, data from healthy individuals (n = 11), patients with ischaemic heart disease (IHD; ejection fraction >40%; n = 9) and patients with heart failure with reduced ejection fraction (HFrEF; EF = 31 (5)%, n = 11), as well as data from swine surgeries, where spontaneous ventricular arrhythmias were observed during cerebrovascular examination (transcranial Doppler ultrasound in humans and laser Doppler in swine) were analysed retrospectively to investigate the effect of arrhythmia on cerebral microvascular haemodynamics. A subset of participants also completed the Montreal Cognitive Assessment (MoCA).

The physiological basis underlying functional connectivity differences in older adults: A multi-modal analysis of resting-state fMRI.

The purpose of this study was to determine if differences in functional connectivity strength (FCS) with age were confounded by vascular parameters including resting cerebral blood flow (CBF), cerebrovascular reactivity (CVR), and BOLD-CBF coupling. Neuroimaging data were collected from 13 younger adults (24 ± 2 years) and 14 older adults (71 ± 4 years). A dual-echo resting state pseudo-continuous arterial spin labeling sequence was performed, as well as a BOLD breath-hold protocol.

Neuroprotective effects of exercise on the aging human neuromuscular system.

Human biological aging from maturity to senescence is associated with a gradual loss of muscle mass and neuromuscular function. It is not until very old age (>80 years) however, that these changes often manifest into functional impairments. A driving factor underlying the age-related loss of muscle mass and function is the reduction in the number and quality of motor units (MUs).

Cerebrovascular insufficiency and amyloidogenic signaling in Ossabaw swine with cardiometabolic heart failure.

Individuals with heart failure (HF) frequently present with comorbidities, including obesity, insulin resistance, hypertension, and dyslipidemia. Many patients with HF experience cardiogenic dementia, yet the pathophysiology of this disease remains poorly understood. Using a swine model of cardiometabolic HF (Western diet+aortic banding; WD-AB), we tested the hypothesis that WD-AB would promote a multidementia phenotype involving cerebrovascular dysfunction alongside evidence of Alzheimer's disease (AD) pathology.

Pathophysiology and management of critical illness polyneuropathy and myopathy.

Critical illness-associated weakness (CIAW) is an umbrella term used to describe a group of neuromuscular disorders caused by severe illness. It can be subdivided into three major classifications based on the component of the neuromuscular system (i.e.

Coexistence of peripheral potentiation and corticospinal inhibition following a conditioning contraction in human first dorsal interosseous muscle.

In skeletal muscle, postactivation potentiation (PAP) is observed following a conditioning contraction (CC) as a large (two- to three-fold) increase in evoked twitch force and rate of force development (RFD). However, this enhancement has not been observed to occur during potentiated voluntary contractions. The purpose of this study was to determine whether the lack of voluntary potentiation may be related to the development of central (corticospinal) inhibition.

Effect of Acute High-intensity Interval Exercise on Whole-body Fat Oxidation and Subcutaneous Adipose Tissue Cell Signaling in Overweight Women.

Exercise-induced alterations in adipose tissue insulin and/or β-adrenergic signaling may contribute to increases in whole-body fat oxidation following acute exercise. Thus, we examined changes in insulin (Akt, AS160) and β-adrenergic (PKA) signaling proteins in subcutaneous adipose tissue and whole-body fat oxidation in overweight women following acute high-intensity interval exercise (HIIE). Overweight females completed two experimental sessions in a randomized order: 1) control (bed rest) and 2) HIIE (10 × 4 min running intervals at 90% HR, 2-min recovery).

Maintaining Motor Units into Old Age: Running the Final Common Pathway.

Invited Letter to the Editor. This article is a commentary on the recently published manuscript "Use it or lose it: tonic activity of slow motoneurons promotes their survival and preferentially increases slow fiber-type groupings in muscles of old lifelong recreational sportsmen". Mosole S, Carraro U, Kern H, Loefler S, Zampieri S.

Electrophysiological and neuromuscular stability of persons with chronic inflammatory demyelinating polyneuropathy.

Introduction: We assessed motor unit (MU) properties and neuromuscular stability in the tibialis anterior (TA) of chronic inflammatory demyelinating polyneuropathy (CIDP) patients using decomposition-based quantitative electromyography.

Methods: Dorsiflexion strength was assessed, and surface and concentric needle electromyography were sampled from the TA. Estimates of MU numbers were derived using decomposition-based quantitative electromyography and spike-triggered averaging.

Motor unit number and transmission stability in octogenarian world class athletes: Can age-related deficits be outrun?

Our group has shown a greater number of functioning motor units (MU) in a cohort of highly active older (∼65 yr) masters runners relative to age-matched controls. Because of the precipitous loss in the number of functioning MUs in the eighth and ninth decades of life it is unknown whether older world class octogenarian masters athletes (MA) would also have greater numbers of functioning MUs compared with age-matched controls. We measured MU numbers and neuromuscular transmission stability in the tibialis anterior of world champion MAs (∼80 yr) and compared the values with healthy age-matched controls (∼80 yr).

Physiology in Medicine: neuromuscular consequences of diabetic neuropathy.

Diabetic polyneuropathy (DPN) refers to peripheral nerve dysfunction as a complication of diabetes mellitus. This condition is relatively common and is likely a result of vascular and/or metabolic disturbances related to diabetes. In the early or less severe stages of DPN it typically results in sensory impairments but can eventually lead to major dysfunction of the neuromuscular system.

Reduced skeletal muscle quantity and quality in patients with diabetic polyneuropathy assessed by magnetic resonance imaging.

Introduction: The aim of this study was to determine whether diabetic polyneuropathy (DPN) is associated with reduced muscle quality using MRI.

Methods: MRIs of the tibialis anterior (TA) muscle were recorded from 9 individuals (5 men) with DPN (∼65 years) and 8 (4 men) age- and gender-matched controls. A magnetization transfer ratio (MTR) and T2 relaxation times of the TA were calculated.

Blood flow and muscle oxygenation during low, moderate, and maximal sustained isometric contractions.

A reduction of blood flow to active muscle will precipitate fatigue, and sustained isometric contractions produce intramuscular and compartmental pressures that can limit flow. The present study explored how blood flow and muscle oxygenation respond to isometric contractions at low, moderate, and maximal intensities. Over two visits, 10 males (26 ± 2 yr; means ± SD) performed 1-min dorsiflexion contractions at 30, 60, and 100% of maximal voluntary contraction (MVC) torque.

Decreased muscle endurance associated with diabetic neuropathy may be attributed partially to neuromuscular transmission failure.

Diabetic polyneuropathy (DPN) can cause muscle atrophy, weakness, contractile slowing, and neuromuscular transmission instability. Our objective was to assess the response of the impaired neuromuscular system of DPN in humans when stressed with a sustained maximal voluntary contraction (MVC). Baseline MVC and evoked dorsiflexor contractile properties were assessed in DPN patients (n = 10) and controls (n = 10).

The altered vestibular-evoked myogenic and whole-body postural responses in old men during standing.

Age-related decrements within the sensorimotor system may lead to alterations and impairments in postural control, but a link to a vestibular mechanism is unclear. The purpose of the present study was to determine whether vestibular control of standing balance is altered with adult aging. Eight old (~77 years) and eight young (~26 years) men stood without aids on a commercially available force plate with their head turned to the right, arms relaxed at their sides and eyes closed while receiving stochastic vestibular stimuli (0-25 Hz, root mean square amplitude=0.