Table 2.

Overview of studies exploring the therapeutic potential of noninvasive cerebellar stimulation techniques in patients with ET

Study	N	Intervention	Sham	Blinding	Protocol	Results
Gironell, 200283	10	1‐Hz cerebellar rTMS, applied 2 cm below the inion (butterfly coil)	Yes	Patients and outcome assessor	30 trains of 10 seconds with pauses of 30 seconds; crossover design	Improvement of tremor severity 5 minutes after real stimulation, but not 60 minutes after rTMS (FTMTRS and accelerometry)
Popa, 201386	11	Neuronavigation‐guided 1 Hz bilateral cerebellar rTMS (figure‐of‐eight coil)	No	N/A	15 minutes of stimulation of each cerebellar hemisphere during 5 consecutive days	Improvement of tremor severity, writing/drawing, and tremor‐related functional disability at days 5, 12, and 29 Increased functional connectivity between the cerebellum and the motor cortex at day 5
Gironell, 201484	10	tDCS; two cathodes 3 cm left and right from the inion, two anodes over the prefrontal areas	Yes	Patients and outcome assessor	20 minutes of stimulation, 2 mA; 5 days per week for 2 weeks; crossover design	No changes in tremor severity at days 10 and 40 (FTMTRS and accelerometry)
Bologna, 201581	16	Cerebellar cTBS, applied 1 cm below the inion and 3 cm to the right (figure‐of‐eight coil)	Yes	Patients and outcome assessor	Triplets of 50‐Hz stimuli, repeated at 5 Hz for 40 seconds; crossover design	No excitability change in the left motor cortex No change in tremor severity, amplitude, frequency, and reaching movements (FTMTRS and kinematics)
Helvaci Yilmaz, 201685	6	tDCS; two anodes over the dorsolateral prefrontal areas, cathode over the inion	No	N/A	20 minutes of stimulation, 2 mA; 5 days per week for 2 weeks; 1 month later, 5 more sessions every other day	No differences in TETRAS scores between baseline and day 20; lower TETRAS score at day 50 Improvement in ADL scores at days 20 and 50
Shin, 201987	22	1‐Hz cerebellar rTMS, applied 3 cm lateral and 1 cm inferior to the inion over both hemispheres (figure‐of‐eight coil)	Yes	Patients	20 trains of 30 seconds with pauses of 10 seconds over each cerebellar hemisphere; 5 consecutive days	Decrease in total FTMTRS score, including subscales A and B (clinical severity), but not C (daily life activities), immediately and after 4 weeks in both groups without significant group effect

TETRAS, The Essential Tremor Rating Scale; rTMS, repetitive transcranial magnetic stimulation; FTMTRS, Fahn‐Tolosa‐Marin Tremor Rating Scale; cTBS, continuous theta burst stimulation; ADL, activities of dailyliving; N/A, not applicable.