We present a video of three patients referred to a Movement Disorders specialist (E.D.L.) for evaluation and management of tremor. Two of the three (i.e., patients 1 and 3) had pre-existing diagnoses of ET; in a third (i.e., patient 2), the referring diagnosis was uncertain. On examination, patients were directed to fully straighten their arms at the elbow, wrist, and fingers, but without overstressing; they were assessed in three arm positions (i.e., pronation, “karate chop”, and wing positions). All patients exhibit hand tremor as well as asymmetric, dystonic posturing of the hands, specifically “spooning”, i.e., wrist flexion and metacarpophalangeal hyperextension (Video 1). In one patient (patient 2), the examination is further notable for concomitant cervical dystonia. In all cases, the diagnosis was ultimately revised to or established as dystonia given these features and failure to fulfill ET diagnostic criteria (e.g., irregularity or jerkiness of tremor).1
Video 1.
Clinical Phenomenology. Patient 1. Examination with arms extended in the “karate chop” position demonstrates episodic postural hand tremor and bilateral “spooning”. Patient 2. Examination with arms extended in the “karate chop” position demonstrates. (A) Episodic, irregular postural hand tremor and “spooning” on left, with superimposed jerky movements and (B) episodic head tremor with head turn to left and hypertrophy of the right sternocleidomastoid muscle, consistent with concomitant cervical dystonia. Patient 3. Examination with arms extended and pronated demonstrates bilateral, episodic postural hand tremor and unilateral “spooning” on left.
Given the heterogeneity of presentation and relative rarity of the disorder, the clinical diagnosis of dystonia can be challenging. Diagnostic confusion is particularly common between dystonia and other movement disorders. Among initially misdiagnosed cases, revision of diagnosis requires recognition of both features atypical for the initial diagnosis and features specifically suggestive of dystonia.2
Initial misdiagnosis of dystonia as ET is not uncommon. In a retrospective case series of 71 patients with pre-existing diagnoses of ET referred for evaluation at a movement disorders center, diagnosis (by Movement Disorders Society 1998 consensus guidelines3) was ultimately revised in 26 (36.6%); in six (8.5%) cases, the diagnosis was revised to isolated dystonia.4 The presence of dystonic posturing, including spooning, was associated with revision of diagnosis, noted to be over 10-fold more likely among those whose diagnosis was revised than those whose diagnosis was confirmed as ET. The presence of other dystonic features, including tremor null point or directionality, and sensory trick, was also associated with revision of diagnosis.
Spooning has not been documented in the general population, but it should be noted that overextending the arms may sometimes produce a posture that resembles spooning. Hence, it is important to ask examinees not to overstress their extended arms during the examination.
We propose that recognition of subtle clinical features of dystonia such as spooning during evaluation of tremor may aid in the diagnosis of underlying dystonia and, ultimately, initiation of appropriate treatment.
Notes
[1] Funding: None.
[2] Financial disclosure Financial Disclosures: None.
[3] Conflicts of Interest: The authors report no conflict of interest.
[4] Ethics Statement: All patients that appear on video have provided written informed consent; authorization for the videotaping and for publication of the videotape was provided.