Archive | Studies on tDCS and Pain

RSS feed for this section

Crossover design in transcranial direct current stimulation studies on motor learning: potential pitfalls and difficulties in interpretation of findings.

Related Articles

Crossover design in transcranial direct current stimulation studies on motor learning: potential pitfalls and difficulties in interpretation of findings.

Rev Neurosci. 2018 Jun 27;29(4):463-473

Authors: Biabani M, Farrell M, Zoghi M, Egan G, Jaberzadeh S

Abstract
Crossover designs are used by a high proportion of studies investigating the effects of transcranial direct current stimulation (tDCS) on motor learning. These designs necessitate attention to aspects of data collection and analysis to take account of design-related confounds including order, carryover, and period effects. In this systematic review, we appraised the method sections of crossover-designed tDCS studies of motor learning and discussed the strategies adopted to address these factors. A systematic search of 10 databases was performed and 19 research papers, including 21 experimental studies, were identified. Potential risks of bias were addressed in all of the studies, however, not in a rigorous and structured manner. In the data collection phase, unclear methods of randomization, various lengths of washout period, and inconsistency in the counteracting period effect can be observed. In the analytical procedures, the stratification by sequence group was often ignored, and data were treated as if it belongs to a simple repeated-measures design. An inappropriate use of crossover design can seriously affect the findings and therefore the conclusions drawn from tDCS studies on motor learning. The results indicate a pressing need for the development of detailed guidelines for this type of studies to benefit from the advantages of a crossover design.

PMID: 29232195 [PubMed – indexed for MEDLINE]

Review this!

Cortico-cerebellar Networks Drive Sensorimotor Learning in Speech.

Related Articles

Cortico-cerebellar Networks Drive Sensorimotor Learning in Speech.

J Cogn Neurosci. 2018 04;30(4):540-551

Authors: Lametti DR, Smith HJ, Freidin PF, Watkins KE

Abstract
The motor cortex and cerebellum are thought to be critical for learning and maintaining motor behaviors. Here we use transcranial direct current stimulation (tDCS) to test the role of the motor cortex and cerebellum in sensorimotor learning in speech. During productions of “head,” “bed,” and “dead,” the first formant of the vowel sound was altered in real time toward the first formant of the vowel sound in “had,” “bad,” and “dad.” Compensatory changes in first and second formant production were used as a measure of motor adaptation. tDCS to either the motor cortex or the cerebellum improved sensorimotor learning in speech compared with sham stimulation ( n = 20 in each group). However, in the case of cerebellar tDCS, production changes were restricted to the source of the acoustical error (i.e., the first formant). Motor cortex tDCS drove production changes that offset errors in the first formant, but unlike cerebellar tDCS, adaptive changes in the second formant also occurred. The results suggest that motor cortex and cerebellar tDCS have both shared and dissociable effects on motor adaptation. The study provides initial causal evidence in speech production that the motor cortex and the cerebellum support different aspects of sensorimotor learning. We propose that motor cortex tDCS drives sensorimotor learning toward previously learned patterns of movement, whereas cerebellar tDCS focuses sensorimotor learning on error correction.

PMID: 29211651 [PubMed – indexed for MEDLINE]

Review this!