Patients with focal dystonia take advantage of certain cutaneous or proprioceptive sensory inputs to alleviate their symptoms ("sensory trick"). We examined the effects of increasing muscle spindle activity by the tonic vibration reflex maneuver and decreasing it by intramuscular injection of lidocaine. The vibration was applied to the palm or the tendon of forearm muscles in 15 patients with writer's cramp and 15 age-matched normal subjects. In 11 patients, the vibration induced dystonic postures or movements typical of those seen during writing. Normal subjects showed either no response to the vibration or a gradually developing tonic vibration reflex only in the wrist and finger flexors, which produced visible movements with a significantly longer latency (12.5 +/- 6.7 seconds [mean +/- standard deviation]) than what was observed in the patients (2.7 +/- 2.5 seconds, p < 0.0001). Local injection of lidocaine (0.5%, 5-40 ml/muscle) attenuated the tendon reflex with relatively little effect on the M response. Injection into muscles with increased activity produced marked reduction of dystonic movements and significant clinical improvement in 13 patients, whereas injection into the other muscles had no effect. The clinical benefit lasted for 1 to 24 hours after injection. In 13 patients who had additional injections of 10% ethanol, which blocks sodium channels for a longer period than does lidocaine, the duration of action was prolonged to 5 to 21 days. These findings suggest that muscles causing dystonic movements have abnormal sensitivities to vibration at rest and that muscle afferents may play a pivotal role in producing dystonic movements.(ABSTRACT TRUNCATED AT 250 WORDS)

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Type F botulinum toxin can be used for treating patients with dystonia who become refractory to type A toxin injection due to antibody development. We compared the therapeutic efficacy of type F botulinum toxin to that of type A toxin in a self-controlled, double-blind clinical trial. In nine patients with blepharospasm, we injected type A toxin on one side and the same units of type F toxin on the other side. Although the onset of clinical effect, maximal benefit, and adverse reactions were similar between type A and F toxins, the duration of the clinical effect was significantly shorter on the side injected with type F toxin. Although type F toxin proved its promise as an alternative to type A toxin, its usefulness is limited by the shorter duration of action.

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This study was performed to determine the rates of breastfeeding among singletons, twins and triplets in Japan, and identify factors associated with the decision to breastfeed or bottle-feed. We analyzed a database of medical check-up of infants aged 3 to 6 months between April 2001 and July 2004 in Nishinomiya City in Japan. This medical check-up is given to almost 100% of infants in Japan and the data of 15,262 infants were analyzed. Among these, 14,963 (98.0%) were singletons, 290 (1.9%) were twins and 9 (0.1%) were triplets. Exclusive breast-feeding was chosen by 6680 (43.8%) mothers, mixed-feeding by 4645 (30.4%) mothers, and bottle-feeding with formula milk only by 3900 (25.6%) mothers. The rate of exclusive breastfeeding among twins or triplets was significantly lower than among singleton babies: 4.1% among twins or triplets, and 44.7% among singletons. Moreover, twins and triplets were independently associated with a higher rate of bottle-feeding: the odds ratio indicated that mothers who had twins or triplets were 2.44 times more likely to choose bottle-feeding with formula milk only than those who had singletons. Sucking ability at birth was associated with a higher rate of bottle-feeding: the odds ratio indicated that mothers who had infants with poor sucking ability at birth were 1.56 times more likely to choose bottle-feeding as those who had infants with normal sucking ability.