PMC

Examples of the effect of local muscle weakness on muscle forces during gait. Top row: GMED weakness; middle row: plantarflexor (GAS+SO) weakness; bottom row: iliopsoas (PSO+IL) weakness. Lighter colors give strength values at increasing levels of weakness, from black = normal force (0% weakness) to light blue = total strength loss (100% weakness). 100% weakness was not possible for plantarflexors. Each line represents the average over 6 subjects. Abbreviations: GMED, gluteus medius; GMIN, gluteus minimus; GMAX, gluteus maximus; TFL, tensor fascia lata; SMM, semimembranosus; PSO, psoas; GAS, gastrocnemius; SO, soleus; TP, tibialis posterior; PERL, peroneus longus; BFS, biceps femoris short head; TA, tibialis anterior; IL, iliacus; RF, rectus femoris; ADL, adductor longus.

Small allele size (repeat length), age at diagnosis and initial symptoms. When comparing initial presenting symptoms to age at diagnosis and repeat length, we see a cluster of facial weakness (1 = dark blue dots) in individuals with the smallest repeat lengths (1–3 repeats = 10–18 kb allele size). We also see a cluster of proximal upper extremity weakness (3A = green dots) in individuals with medium (4–7 repeats; 18–30 kb allele size) repeat lengths. Right axis: 1 = facial weakness; 2 = trunk weakness; 3A = proximal upper extremity (UE) weakness; 3B = distal UE weakness; 3C = unspecified UE weakness; 4A = proximal lower extremity (LE) weakness; 4B = distal LE weakness; 4C = unspecified LE weakness; 5A = pain in the back/trunk; 5B = pain in the UE; 5C = pain in the LE; 6 = fatigue or generalized weakness; 7 = atrophy or loss of muscle mass; 8 = muscle cramps; 9 = abnormal laboratory values; 10 = family history of FSHD; 11 = no symptoms; 12A = injury due to falling; 12B = injury not due to falling; 13 = unable to classify; 14 = sensory changes; N = missing data.

Illustration of the 6MWT (a) and the FIM (b) at hospital discharge with non-parametric Cuzick test clearly rejecting the null hypothesis in favour of alternative: values for severe weakness < no weakness and for severe weakness ≤ moderate weakness vales ≤ no weakness.

EMG, electromyography; ICU-AW, intensive care unit–acquired weakness; MRC, Medical Research Council; NCS, nerve conduction study; NM, neuromuscular. Modified from Latronico and Bolton .