Drop attacks in the elderly: effect of pyridostigmine.

Sir, Elderly people are prone to sudden unexplained falls, usually categorized as 'drop attacks', a definition excluding those in whom the falls are accompanied or preceded by changes in the level of consciousness or by vertigo."2 The event is unpredictable and hence potentially dangerous, and constitutes the major type of home accident amongst people over the age of 65.3 The basic abnormality to which the falls may be attributable has not so far been clarified, but is not usually considered to be connected with the frequent cardiac or cerebral vasculopathy common in the age group.2 An approach to the question of the underlying pathophysiology of the disorder was put forward by Weiner et al.4 who found postural reflex impairment in 44% (severe) and 24% (moderate) of 34 such patients. The possibility of the immediate cause of the fall being a failure to generate tension in the quadriceps muscles sufficiently quickly to maintain erect posture has also been mooted.5 This concept of a causal momentary failure in the peripheral neuromuscular circuit is somewhat reminiscent of the familiar clinical sign in spastic paraparesis characterized by sudden collapse of muscle resistance to passive stretching. Preventive treatment has so far been limited to various means of special attention to daily care of susceptible individuals3'6 with medication limited to that required for coexistent disorders (success has recently been reported7 following treatment of hypothyroidism). The concept referred to above of impaired maintenance of quadriceps tension, prompted a trial of the anti-cholinesterase pyridostigmine, as a possible means of somehow aiding maintenance of the neuromuscular contraction mechanism. This agent has been prescribed in six individuals (three men, three women) aged 6573 with typical drop attacks as defined, occurring several times a month. Two patients suffered from moderate hypertension; at the onset of therapy none had any abnormal neurological findings, but one female followed for 2 years subsequently developed signs and symptoms compatible with multiple system atrophy. In this patient, the two other females and one male, drop attacks ceased with onset of therapy. The male patient agreed to suspend medication in advance of electromyography studies for possible myasthenia gravis (which were negative); attacks returned 2 weeks later and ceased once more on resumption of treatment. Two females refused to stop therapy. All patients were started and kept on a dosage of60 mg pyridostigmine twice daily and none of them reported any undesirable side effects on this regime. In those responding favourably, benefit resulted from the onset of treatment and was subsequently maintained, the longest period being 4 years to date. This limited series may not justify conclusions at present, but I believe the drug to be worth trying in patients whose falls cannot be attributed to any clear aetiological causation. Jackson Braham Department of'Neurology, Sheba Medical Centre, Tel Hashomer, Ramat-Gan, Tel Aviv University Medical School, Israel. References