PT  - JOURNAL ARTICLE
AU  - Michele Tinazzi
AU  - Alfonso Fasano
AU  - Alessandro Di Matteo
AU  - Antonella Conte
AU  - Francesco Bove
AU  - Tommaso Bovi
AU  - Alessia Peretti
AU  - Giovanni Defazio
AU  - Mirta Fiorio
AU  - Alfredo Berardelli
TI  - Temporal discrimination in patients with dystonia and tremor and patients with essential tremor
AID  - 10.1212/WNL.0b013e31827b1a54
DP  - 2013 Jan 01
TA  - Neurology
PG  - 76--84
VI  - 80
IP  - 1
4099  - http://n.neurology.org/content/80/1/76.short
4100  - http://n.neurology.org/content/80/1/76.full
SO  - Neurology2013 Jan 01; 80
AB  - Objective: To investigate whether psychophysical techniques assessing temporal discrimination could help in differentiating patients who have tremor associated with dystonia or essential tremor.Methods: We tested somatosensory temporal discrimination thresholds (TDT) and temporal discrimination movement thresholds (TDMT) in 39 patients who had tremor associated with dystonia or essential tremor presenting with upper-limb tremor of comparable severity and compared their findings with those from a group of 25 sex- and age-matched healthy control subjects.Results: TDT was higher in patients who had tremor associated with dystonia than in those with essential tremor and healthy controls (110.6 ± 31.3 vs 63.1 ± 15.2 vs 62.4 ± 9.2; p < 0.001). Conversely, TDMT was higher in patients with essential tremor than in those with tremor associated with dystonia and healthy controls (113.7 ± 14.7 vs 103.4 ± 11.3 vs 100.4 ± 4.2; p < 0.001). Combining the 2 tests in a pattern for essential tremor (abnormal TDMT/normal TDT) and tremor associated with dystonia (normal TDMT/abnormal TDT) yielded a positive predictive value (PPV) of 86.7% and a negative predictive value (NPV) of 70.8% for diagnosing essential tremor and a PPV of 100.0% and NPV of 74.1% for diagnosing tremor associated with dystonia.Conclusions: TDT and TDMT testing should prove a useful tool for differentiating tremor associated with dystonia and essential tremor. Our findings imply that the pathophysiologic mechanisms underlying tremor associated with dystonia differ from those for essential tremor.123I-FP-CIT SPECT=123I-labeled N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl)nortropane SPECT; ANOVA=analysis of variance; CI=confidence interval; cTBS=continuous theta-burst stimulation; ET=essential tremor; FCR=flexor carpi radialis; FDI=first dorsal interosseous; HC=healthy control; ISI=interstimulus interval; NPV=negative predictive value; PPV=positive predictive value; TAD=tremor associated with dystonia; TDMT=temporal discrimination movement threshold; TDT=temporal discrimination threshold; TRS=Tremor Rating Scale