An attempt to explain the mechanism of drop attacks.
We have investigated the possibility that a delay in long-loop (transcortical) reflexes might be responsible for the occurrence of drop attacks which occur in middle-aged women without disturbance of consciousness. We have not been able to confirm this suggestion. However, using simple Newtonian principles, we calculate how far the subject may fall before a long-loop reflex can be generated in the quadriceps muscle. We suggest that in some subjects tension cannot be generated sufficiently quickly to maintain the erect posture. This hypothesis provides a link between subjects who experience drop attacks due to overt muscle weakness and subjects without physical signs.
D000328:Adult; D001696:Biomechanical Phenomena; D002540:Cerebral Cortex / Q000503:physiopathology; D004576:Electromyography; D005260:Female; D006801:Humans; D007717:Knee / Q000503:physiopathology; D008875:Middle Aged; D009132:Muscles / Q000503:physiopathology; D004856:Postural Balance; D012026:Reflex, Stretch; D013116:Spinal Cord / Q000503:physiopathology; D013575:Syncope / Q000209:etiology*