Drop attack (DA) is defined as a sudden fall, without loss of consciousness, vertigo, or myoclonic associated jerks, followed by a prompt recovery of stance. 64% of the cases have unknown origin. In this work we describe the case of a 31 years old female suffering from sudden falls since she was 24 years old. These falls were more frequent when the subject felt her lower limb tired and were evoked by specific visual stimuli, such as high contrast pictures with brilliant colours or striped patterns. The attacks have been evoked under controlled conditions and monitored by a video-EEG-poligraphic technique. Stroboscopic light stimulation (13-20 Hz) evoked short lower limb akinetic episodes without any EEG change. The presentation of optokinetic stimuli induced similar abrupt falls. Voluntary leg muscles contraction hindered the falls. EEG recordings, both in awake or sleeping condition, didn't show any pathological modification. The same was for MR scanning of the brain and of the spinal cord. The authors conclude that the drop attacks observed in this case are of idiopathic, dysfunctional origin, the underlying mechanism involving the optokinetic pathway. In fact, it is known that through this way the visual input reaches the structures controlling gaze stability and postural tone at brainstem level.
Drop Attacks. A proposito di un caso clinico
BOTTI, Fabio Massimo;
1999
Abstract
Drop attack (DA) is defined as a sudden fall, without loss of consciousness, vertigo, or myoclonic associated jerks, followed by a prompt recovery of stance. 64% of the cases have unknown origin. In this work we describe the case of a 31 years old female suffering from sudden falls since she was 24 years old. These falls were more frequent when the subject felt her lower limb tired and were evoked by specific visual stimuli, such as high contrast pictures with brilliant colours or striped patterns. The attacks have been evoked under controlled conditions and monitored by a video-EEG-poligraphic technique. Stroboscopic light stimulation (13-20 Hz) evoked short lower limb akinetic episodes without any EEG change. The presentation of optokinetic stimuli induced similar abrupt falls. Voluntary leg muscles contraction hindered the falls. EEG recordings, both in awake or sleeping condition, didn't show any pathological modification. The same was for MR scanning of the brain and of the spinal cord. The authors conclude that the drop attacks observed in this case are of idiopathic, dysfunctional origin, the underlying mechanism involving the optokinetic pathway. In fact, it is known that through this way the visual input reaches the structures controlling gaze stability and postural tone at brainstem level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
