DISCUSSION
The “yips,” or intermittent, transient tremors, jerks, or spasms3 that are seen in athletes, are well-documented in the lay press, but haven’t been significantly addressed in the medical literature.4 Stigma surrounding the condition among athletes likely leads to under-reporting. Athletes typically experience yips with fine motor movements, such as short putts in golf and pitching in baseball. In fact, while the majority of the medical literature on yips revolves around golfers, many talented baseball players have had their careers altered by the condition. The yips may also affect movements in sports like darts, cricket, table tennis, and billiards.
In 1984, dystonia was defined as a disorder of sensorimotor integration that results in co-contraction of agonist/antagonist muscles, and may be characterized by state dependence (exacerbation with specific activities) or sensory tricks (amelioration with specific types of sensory input).5 In 2013, the definition was revised to remove “co-contraction” from the definition because phenomenology alone is sufficient to make the diagnosis.1
Many athletes and sports fans believe the yips are caused by performance anxiety or related phobias, but evidence suggests that many athletes with the movement disorder may actually have focal limb dystonia.6,7 The yips can, however, lead to performance anxiety,3 but there has been no difference noted between the anxiety level of golfers with or without the yips.7 Psychological treatment approaches are commonly employed, but surface electromyograms have shown abnormal co-contraction of wrist flexor and extensor muscles in 5 out of 10 golfers with the yips (but 0 of those without) while putting—which is consistent with focal limb dystonia.8
Botulinum toxin injections are Tx of choice, but can cause weakness
Muscle relaxers, such as baclofen and benzodiazepines, as well as dopamine antagonists, can ameliorate dystonia.9 Focal limb dystonia may also respond to the antispasmodic trihexyphenidyl, but the dose must often be limited due to adverse effects such as nausea, dizziness, and anxiety.10
Botulinum toxin injections have proven effective for focal limb dystonia11 and are considered the treatment of choice. However, there are few reports on their use in athletes, where the adverse effect of weakness could affect performance. One case report also showed improvement of yips with acupuncture, although this has not been extensively studied.12
Our patient didn’t respond to low-dose (2 mg twice a day) trihexyphenidyl. Tetrabenazine, a dopamine depletor frequently used for hyperkinetic disorders, was not effective at 25 mg taken prior to coaching sessions. Higher doses of an anticholinergic could have been effective, but the patient declined our recommendation to pursue this (or botulinum toxin injections). He decided instead to train himself to use his left arm while coaching.