Nakane S, Ando Y, Matsuo H. Yips preceding baseball-related dystonia. Parkinsonism Relat Disord. 2018 Feb 11. pii: S1353-8020(18)30054-3. doi:10.1016/j.parkreldis.2018.02.018. [Epub ahead of print]
Yips is a multi-etiological phenomenon that is characterized by involuntary movements during the execution of fine motor skills in athletes. Yips manifests as twitches, transient tremors, staggers, jitters, and jerks. The etiology of yips involves a neurological origin associated with focal dystonia and a psychological origin linked to choking under pressure. The pathophysiology of yips is poorly understood and there is no known treatment.
A 15-year-old, right-handed high school baseball player (Patient 1) complained of stiffness and abnormal movements of the right shoulder and upper arm, triggered by moving the right arm. He pitched with the right hand. He had started began to playing baseball at the age 6 years, and had won an athletic scholarship in during at the high school registration. Because as he predominantly threw more balls than performed strikes in several games, his teammates jeered mocked at him. Owing to the resulting decline in his performance, he adopted an intensive training load (6–7 hours daily) and paid special attention to pitching. A feeling of discomfort in his right hand and fingertips bothered him. Three months later, he suffered injuries such as bruises on the right shoulder, and began to experience involuntary abnormal shoulder anteflexion during training. Finally, he reported that the involuntary movements always occurred during his daily-life activities, requiring elbow flexion, and frequently dislocated his right shoulder joint. He was observed to exhibit dystonic movements characterized by elbow flexion associated with elevation and adduction of the shoulder that occurred almost each time he moved his shoulder, elbow, and hand (video 1). He was able to attenuate the abnormal movement by using a sensory trick namely, clutching the right upper arm with his left hand. We diagnosed baseball-related focal dystonia. We attentively listened to his distress, including disputes among the teammates, and advised the patient to drastically reduce his total practice load and to exclude all repetitive movements of the right upper limb. Additionally, we decided to administer a muscle afferent block (MAB) for focal dystonia. 0.5% lidocaine was injected into the deltoid, trapezius, and pectoralis major muscles. We performed the MAB treatment 5 times for 3 month. After 4 months, normal training sessions including playing catch were resumed gradually. His condition had improved significantly 1.5 years after onset (video 2). The dystonia slightly persisted; he contributed to the team as a pinch hitter.
Dhungana S, Jankovic J. Yips and other movement disorders in golfers. Mov Disord. 2013 May;28(5):576-81.
Golf is a sport that requires perfect motor coordination and a balance between mobility and stability. Golfer's "yips," an intermittent motor disturbance manifested as transient tremor, jerk, or spasm that primarily occurs when the player is trying to chip or make a putt, is a movement disorder frequently encountered in both amateur and professional golfers. In addition, other movement disorders, such as tremors and dystonia, also can interfere with playing golf. Although the pathophysiology of the yips remains poorly understood, recent studies suggest that it may be a form of a task-specific, focal dystonia involving the hand and arm. Because task-specific dystonias and tremors are best treated by botulinum toxin injections, this also may be an effective therapy for the yips. The aim of this article is to systematically review the literature and our own experience with the yips and other movement disorders in golfers.
McDaniel KD, Cummings JL, Shain S. The "yips": a focal dystonia of golfers. Neurology. 1989 Feb;39(2 Pt 1):192-5.
The "yips" is an involuntary motor disturbance affecting golfers. A 69-item questionnaire was constructed and distributed to 1,050 professional and amateur golfers in an effort to define and characterize this syndrome. Of the male golfers there was a 42% response rate and 28% reported suffering from the yips. The disorder was described most frequently as jerks, tremors, and spasms affecting the preferred arm distally and primarily during putting. When compared with unaffected golfers, afflicted golfers were significantly older and had more cumulative years of golfing. In 24%, activities other than golfing were affected and 25% reported involvement of body regions beyond the arms. These data support the hypothesis that the yips represents a focal dystonia and shares many features with other occupational dystonias.