Dystonia Associated with Idiopathic Slow Orthostatic Tremor

Christopher Kobylecki; Monty A. Silverdale; Jeremy P. R. Dick; Mark W. Kellett; Andrew G. Marshall

doi:10.5334/tohm.259

Figures & Tables

Video 1

Patient 6, Video Clip A. The video shows a jerky asymmetrical postural tremor with dystonic posturing of the right upper limb, and jerky dystonic head tremor.

Table 1

Clinical and Neurophysiological Characteristics of Patients with Slow Orthostatic Tremor

Patient Number	Age/Sex	Duration (years)	Clinical Features	Treatment	Rest Tremor	EMG Burst Duration (ms)	Orthostatic Tremor	Investigations
1	70/F	6	LL rest tremor LL tremor on standing Asymmetric R>L rest, postural, action UL tremor + jaw tremor No parkinsonism	Levodopa – Gabapentin + Clonazepam +	R UL 4.6 Hz R>L LL 5.2 Hz	80–100	R>L 5.8 Hz (increased amplitude)	[¹²³I]-FP-CIT SPECT normal
2	77/F	15	Retrocollis initially LL tremor on walking, no rest tremor Intermittent R hand postural tremor	BTX + (retrocollis) Clonazepam nt	None	50–60	8 Hz	–
3	43/M	8	LL/truncal tremor on standing, improved when walking Slight LL rest tremor Dystonic posturing R>L UL, increased when writing Asymmetric jerky postural UL tremor Cervical dystonia and head tremor No parkinsonism	Clonazepam – Propranolol – Levodopa – Topiramate – Primidone + Alcohol+THP–	None	80	5.3 Hz	Copper studies normal SCA genetics negative
4	33/M	16	Jerky head tremor, cervical dystonia Moderate jerky L UL rest, postural, action tremor LL tremor on standing No parkinsonism	Propranolol + Topiramate – BTX + (head tremor)	L UL 6 Hz No LL tremor	60–150	7.5 Hz	Copper studies normal
5	62/M	12	LL tremor and unsteady when standing still No LL rest tremor Jerky UL R>L postural, action>rest tremor No parkinsonism	THP – Levodopa +/– Topiramate –	UL 6.5 Hz LL 6.5 Hz	60–80	6.25 Hz	[¹²³I]-FP-CIT SPECT normal
6	53/F	4	UL jerky postural tremor R>L, increased with action Dystonic posturing R>L UL Unsteady on standing, slow OT improved on walking Head tremor, left torticollis No parkinsonism	Alcohol + SSRI + Metoprolol + Primidone nt THP +	–	150	4-5 Hz	Copper studies normal
7	50/F	6	LL tremor, unsteady when standing still Jerky head tremor, cervical dystonia R>L rest tremor UL/LL R>L jerky postural tremor UL Writer’s cramp No parkinsonism	Propranolol + Levodopa +	R LL 4 Hz L LL 5 Hz	100–120	R LL 6 Hz L LL 5 Hz	Copper studies normal
8	46/F	2	LL tremor, unsteady on standing Head tremor, UL action tremor R torticollis, jerky head tremor No rest tremor Jerky UL action tremor Slow OT on standing	Primidone nt Clonazepam nt THP +	LL 5 Hz		R LL 7 Hz L LL 7.5 Hz	Copper studies normal

[i] Abbreviations: +, Benefit from Treatment; −, No Effect or Worsening; BTX, Botulinum Toxin; EMG; FP-CIT SPECT; L, Left; LL; nt, Not Tolerated; OT, Orthostatic Tremor; R, Right; SCA; SSRI, Selective Serotonin Reuptake Inhibitor; THP, Trihexiphenidyl; UL.

**Neurophysiological Analysis in Patients 7 (Left Column) and 8 (Right Column).** (A,B) Raw electromyography recordings from right (top) and left (bottom) tibialis anterior (TA) over a 1-second epoch. (C,D) Power spectra from right and left TA demonstrating dominant peaks at 6–7 Hz for both patients. (E,F) Intralimb (right TA – right medial gastrocnemius) and interlimb (right TA – left TA) coherence analysis. The horizontal line represents the 5% significance level for the null hypothesis of zero coherence, and values above this line therefore show significant coherence.

Video 2

Patient 6, Video Clip B. Slow pseudo-orthostatic tremor is evident on standing.

Video 3

Patient 7, Video Clip A. At rest this patient displays mild right sided rest tremor of upper and lower limbs. There is a jerky mixed head tremor. On posture holding she shows jerky right more than left upper limb tremor with dystonic right upper limb posturing and position specificity.

Video 4

Patient 7, Video Clip B. Gait is normal with no evidence of tremor until she stands still, at which point slow pseudo-orthostatic tremor is again seen.

Video 5

Patient 8, Video Clip A. At rest the patient has right torticollis with a jerky head tremor. There is action tremor of the upper limbs with no bradykinesia.