Table 2.

References addressing cortical inhibition/excitation in patients with focal hand dystonia (FHD), cervical dystonia (CD), benign essential blepharospasm (BEB), generalized (gen), or DYT1 dystonia (DYT1). The number after the year reflects position in the reference list. Under Participants, N_D and N_C respectively denote dystonia and control sample sizes, R denotes age range, M denotes mean (standard deviation), and D denotes duration of symptoms, all in years.

Author/Year	Participants	Type	Technique / Design	Key Findings
Abbruzzese, 2001 [27]	ND: 21, NC: 16, R: 28–78, D: 1–27	FHD, CD	TMS targeting APB, median nerve stimulation	Inhibitory effect of median nerve stimulation in CD and controls, but not in FHD.
Amadio, 2014 [39]	ND: 8, NC: 8, R: 30–61	CD	TMS w/wo sensory trick application	Sensory tricks reduced abnormal intracortical facilitation, suggesting improved M1 cortical inhibition.
Antelmi, 2016 [16]	ND: 19, NC: 19, M: 62.6 (9.2), D: 9.42 (4.7) 3 months post botox injection	CD	SEP recording	S1 disinhibition in CD, compared to healthy controls.
Baker, 2003 [56]	ND: 5, NC: 5, R: 50–62	BEB	BOLD activation mapping during spontaneous / voluntary blinking	Anterior visual cortex, central thalamus, and superior cerebellum activation larger patients than controls.
Beck, 2008 [107]	ND: 16, NC: 20, R: 43–72, D: 3–39	FHD	EMG recording of APB during isometric FDI flexion. TMS used to measure inhibition	Patients failed to modulate APB activity during FDI contraction and showed decreased inhibition to APB. This was prominent during movement initiation.
Beck, 2009 [109]	ND: 13, NC: 12, R: 44–73, D: 3–39	FHD	TMS targeting abductor pollicis brevis (APB)	Reduced IHI in mirror dystonia, but not in FHD patients without mirroring.
Blood, 2004 [78]	ND: 8, NC: 5, R: 31–58	FHD	fMRI during bilateral finger tapping	Higher caudate nucleus, putamen, globus pallidus, and M1 activation in FHD patients than controls.
Gilio, 2003 [98]	ND: 10, NC: 8, M: 40 (1.3), D: 2–15	FHD, gen	TMS over M1 targeting wrist extensors	No cortical excitability changes, small intracortical inhibition changes in patients; increased excitability / reduced inhibition in controls.
Hoffland, 2013 [55]	ND: 19, NC: 8, Older adults, D: 13 (7)	CD	Eyeblink conditioning, cerebellar TMS	cTMS improved eyeblink conditioning in CD.
Huang, 2010 [103]	ND: 11, NC: 9, R: 27–57, age at onset: 9–47	FHD, DYT1	rTMS over dorsal premotor cortex	Suppression of cortical excitability in controls and DYT1 dystonia, but not in FHD. rTMS improved intracortical inhibition and writing function in FHD.
Hubsch, 2013 [83]	ND: 21, NC: 25, M: 42.9 (14.3), D: 0.5–31	FHD	TMS over M1 and cerebellum. Correlation with adaptation task.	No sensorimotor plasticity modulation; reduced motor adaptation in patients, more robust cerebellar inhibition.
Hummel, 2002 [104]	ND: 6, NC: 18, R: 29–68	FHD	EEG and TMS during activation or inhibition of motor program	Inhibition of learned motor program was associated with increase in alpha oscillations in controls but not in patients. This suggests increased oscillation is a mechanism by which motor programs are inhibited.
Ridding, 1995 [99]	ND: 15, NC: 8, M: 47 (13)	FHD	TMS over M1 targeting first dorsal interosseous (FDI)	Decreased inhibition of hemisphere controlling the dystonic hand in patients. Similar excitability in patients and controls.
Sitburana, 2009 [106]	ND: 30, NC: 40, M: 51 (11.8), D: 9.7 (7.4)	FHD	Handwriting analysis; repetitive hand tasks	More motor overflow in patients than controls. Mirror overflow most prevalent, followed by ipsi- and contralateral.
Terranova, 2018 [108]	ND: 8, NC: 8, R: 31–66	FHD	Paired associative stimulation (PAS), SEP recording	While facilitation was larger for patients and spatial specificity was lost, inhibition was similar between patients and controls.
Tinazzi, 2000 [15]	ND: 10, NC: 10, M: 45.3 (8.1)	FHD, gen	SEP recording	SEP disinhibition, suggesting impaired afferent input gating, affecting motor excitability.