Assessment of physical fatigability and fatigue perception in myasthenia gravis

Abstract

LT allows quantification of fatigability as an objective measurement of decline in individual performance, even in patients without obvious neuromuscular deficits in routine testing. The missing correlation of experienced fatigue supports the multidimensional fatigue model. Muscle Nerve 55: 657-663, 2017.

Cognitive fatigue in patients with myasthenia gravis

“…A total of 33 MG patients (24 women; 9 men) aged 20 to 82 ( M = 52.6; SD = 17.7) and 17 healthy subjects (12 women; 5 men) aged 21 to 82 years ( M = 46.7; SD = 17.9) were prospectively recruited at the University Neuromuscular Department outpatient clinic, Halle, Germany. Groups did not differ in age or gender proportion (Table ), and the healthy control group was the same as described previously . Diagnosis of MG was based on generalized myasthenic symptoms; presence of AChR or muscle specific tyrosine kinase receptor (MuSK) antibodies; positive decrement in repetitive nerve stimulation; and positive response to symptomatic treatment (pyridostigmine) and/or immunotherapy (Table ).…”

“…Linear trend (LT) reflects the dynamic of individual performance within a defined time period . An LT of “0” indicates stable performance, <“0” represents a decline and indicates cognitive fatigability …”

Estimating and managing fatigue for our patients: Are we measuring up?

“…Fatigability, on the other hand, can be defined as objective changes in performance. In healthy adults, fatigue and fatigability are physiologic reactions to prolonged or intensive activity that typically does not interfere with normal everyday life . In illness, fatigue and fatigability are manifestations that often interfere with activity and QOL.…”

“…In the study by Tran et al, patients with mild (Myasthenia Gravis Foundation of America [MGFA] class II) or moderate (MGFA class III) generalized MG reported, on average, moderate fatigue scores, and patients with severe MG (MGFA Class IV) reported experiencing severe fatigue. 1 Other investigators have also reported subjective fatigue complaints in the majority of patients with MG. [5][6][7][8] When thinking about fatigue in the setting of any disease, we must start by distinguishing fatigue from fatigability, two constructs that, unfortunately, are sometimes conflated. As the authors point out, fatigue is subjective "tiredness" caused by mental and/or physical exertion.…”

“…In healthy adults, fatigue and fatigability are physiologic reactions to prolonged or intensive activity that typically does not interfere with normal everyday life. 5,9,10 In illness, fatigue and fatigability are manifestations that often interfere with activity and QOL. Fatigue and fatigability are common in both central (e.g., Parkinson disease, multiple sclerosis, stroke) and peripheral (e.g., muscle disease) neurological diseases.…”