Among 51 patients with adult-onset hypothyroidism, clinical examination revealed abnormal findings from the peripheral nerves in 12. The electromyogram was abnormal in 18 patients, whereas abnormalities of motor conduction were observed in 19 patients, mainly as a prolonged distal latency. Electroencephalographic abnormalities of different types were detected in 30 of the 41 patients studied.
There is no clear-cut correlation between either EEG or EMG abnormalities with the various metabolic indexes of severity of the disease process. On the other hand, electromyographic evidence of genuine myopathy was only rarely obtained.
Scarpalezos S, Lygidakis C, Papageorgiou C, Maliara S, Koukoulommati AS, Koutras DA. Neural and Muscular Manifestations of Hypothyroidism. Arch Neurol. 1973;29(3):140–144. doi:10.1001/archneur.1973.00490270022002