Abnormal iron deposition associated with the degenerative process could be the source of T2 shortening, which is a useful MR imaging finding in the diagnosis of ALS.

No abstract

The clinical and radiological features in seven patients who had asymmetric muscular atrophy of the hand and forearm when young are reported and a new hypothesis for its aetiology is proposed. Investigation of body growth curves (a surrogate for velocity of arm growth) showed close relation between (a) the age when the body height increased most rapidly and the onset age of this disorder, and (b) the age when the rapid body growth period ended and the age when symptom progression ceased. Cervical radiological evidence is provided showing asymmetric anterior cord atrophy, disappearance of slackness of dorsal roots in neck extension, and anterior and lateral displacement of the lower cervical cord against the posterior aspects of the vertebral bodies during neck flexion. These results suggest that disproportionate shortening of the dorsal roots is further accentuated during the juvenile growth spurt, which determines the onset and self limited course of the condition, and that repeated neck flexion causes microtrauma and relative ischaemia of anterior horn cells, which finally results in atrophy of the muscles innervated by motoneurons with long axons.Predisposing anatomical factors are a straight neck due to lack of physiological cervical lordosis and the presence offoreshortened dorsal roots. (3 Neurol Neurosurg Psychiatry 1995;58:56-64)

No abstract

We conducted overnight polysomnographic sleep studies of 16 patients (5 men and 11 women) with clinically well-controlled myasthenia gravis (MG). The subtypes of MG were IIA (3 patients), IIB (11 patients), IV (1 patient) and V (1 patient). Twelve patients were found on polysomnography to have obstructive and/or central types of the sleep apnoeas (SA). Their mean age was 42.4, SD 16.4 years, and the mean duration of MG was 7.4, SD 6.96 years. SA was not detected in 4 patients whose mean age was 30.8, SD 10.71 years and who had manifested MG for a mean duration of only 0.9, SD 0.65 years. Thus, patients with a longer duration of MG tended to have more SA. In 9 of the 12 SA patients, polysomnographic studies were repeated following thymectomy. SA had resolved in 6 patients, but persisted in 3. These findings suggest that SA is a possible clinical manifestiation of MG and that nocturnal dysfunction of both peripheral and central colinergic systems may be involved.