Table 2.

Potential neurophysiological tests for tremor differential diagnosis

Techniques	Diagnostic reliability	Design	Parkinsonian tremor	Essential tremor	Dystonic tremor	Psychogenic tremor	References
Mean hormonic peak power	Accuracy 94%	Tremulous PD(n = 39) vs. ET(n = 41)	Tremulous PD > ET		-	-	Muthuraman M. Mov Disord. 2011 [47]
Coherence entrainment test (CET)	Accuracy 100%	Psychogenic trmeor (n = 10) vs. DT (n = 11) vs. HC(n = 10)	-	-	negative	positive	McAuley J. Mov Disord. 2004 [50]
Blink reflex recovery curve (BRrc)	Accuracy 100%	DT(n = 10) vs. ET(n = 10) vs. HC(n = 12)	-	Normal	Increased R2 recovery index	-	Nistico R. Neurology. 2012 [51]
	Accuracy 100%	tPD(n = 11) vs. ET with rest tremor(n = 10) vs. HC(n = 20)	Incresed R2 component	Normal at ISI 100	-	-	Nistico R. Parkinsonism Relat. Disord. 2014 [52]
Temporal discrimination movement threshold (TDMT)	PPV 86.7%, NPV 70.8%	ET(n = 19) vs. TAD(n = 20) VS. HC(n = 25)	-	Higher	Normal	-	Tinazzi M. Neurology. 2013 [53]
Somatosensory Temporal discrimination threshold (TDT)	PPV 100.0%, NPV 74.1%	TAD (n = 20) vs. ET(n = 19) VS. HC(n = 25)	-	Normal	Higher	-	Tinazzi M. Neurology. 2013 [53]
Reciprocal inhibition (RI)	Not given	CD with arm tremor(n = 13) vs. ET(n = 8)	-	Normal	Partially reduced	-	Munchau L. Brain. 2001 [54]

TAD Tremor associated with dystonia, DT dystonic tremor, CD cervical dystonia, tPD tremor dominant PD, PPV positive predictive value, NPV negative predictive value, ISI interstimulus intervals, -, not given