Transcranial Direct Current Stimulation in Patients with Prolonged Disorders of Consciousness: Combined Behavioral and Event-Related Potential Evidence

Zhang, Ye; Song, Weiqun; Du, Jing; Huo, Su; Shan, Guojin; Li, Ran

doi:10.3389/fneur.2017.00620

Cited by 64 publications

(94 citation statements)

References 44 publications

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“…According to his report, it seems that part of this improvement has been due to increased levels of participant`s consciousness. This finding is consistent with studies investigated the effect of tDCS on the level of consciousness in normal people (Lauro et al, 2014) and patients with abnormal levels of consciousness (Zhang et al, 2017, Bai et al, 2017. The reduction of speech rate and decreasing palilalia were other goals of this study.…”

Section: Discussionsupporting

confidence: 92%

The clinical outcome of concurrent speech therapy and transcranial direct current stimulation in dysarthria and palilalia following traumatic brain injury: A case study

Bayat¹,

Tahamtan²,

Sabeti³

et al. 2020

Preprint

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Purpose: Dysarthria, a neurological injury of the motor component of the speech circuitry, is of common consequences of traumatic brain injury (TBI). Palilalia is a speech disorder characterized by involuntary repetition of words, phrases, or sentences. Based on the evidence supporting the effectiveness of transcranial direct current stimulation (tDCS) in some speech and language disorders, we hypothesized that using tDCS would enhances the effectiveness of speech therapy in a client with chronic dysarthria following TBI. Method: We applied the constructs of the “Be Clear” protocol, a relatively new approach in speech therapy in dysarthria, together with tDCS on a chronic subject who affected by dysarthria and palilalia after TBI. Since there was no research on the use of tDCS in such cases, regions of interest (ROIs) were identified based on deviant brain electrophysiological patterns in speech tasks and resting state compared with normal expected patterns using the Quantitative Electroencephalography (QEEG) analysis. Results: Measures of perceptual assessments of intelligibility, an important index in the assessment of dysarthria, were superior to the primary protocol results immediately and 4 months after intervention. We did not find any factor other than the use of tDCS to justify this superiority. The percentage of repeated words, an index in palilalia assessment, had a remarkable improvement immediately after intervention but fell somewhat after 4 months. We justified this case with subcortical origins of palilalia. Conclusion: Our present case-based findings suggested that applying tDCS together with speech therapy may improve intelligibility in similar case profiles as compared to traditional speech therapy. To reconfirm the effectiveness of the above approach in cases with dysarthria following TBI, more investigation need to be pursued.

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Section: Discussionsupporting

confidence: 92%

The clinical outcome of concurrent speech therapy and transcranial direct current stimulation in dysarthria and palilalia following traumatic brain injury: A case study

Bayat¹,

Tahamtan²,

Sabeti³

et al. 2020

Preprint

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“…Similarly, the all-or-none difference between R+ and R-during the oddball auditory paradigm supports the postulate identifying the P300 to a specific signature of conscious access (27,(45)(46)(47). This is also consistent with previous findings of an increase P300 amplitude in MCS patients after repetitive tDCS (48).…”

Section: Discussionsupporting

confidence: 90%

Combined behavioral and electrophysiological evidence for a direct cortical effect of prefrontal tDCS on disorders of consciousness

Hermann¹,

Raimondo²,

Hirsch³

et al. 2019

Preprint

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Severe brain injuries can lead to long-lasting disorders of consciousness (DoC) such as vegetative state/unresponsive wakefulness syndrome (VS/UWS) or minimally conscious state (MCS). While behavioral assessment remains the gold standard to determine conscious state, EEG has proven to be a promising complementary tool to monitor the effect of new therapeutics. Encouraging results have been obtained with invasive electrical stimulation of the brain, and recent studies identified transcranial direct current stimulation (tDCS) as an effective approach in randomized controlled trials. This non-invasive and inexpensive tool may turn out to be the preferred treatment option. However, its mechanisms of action and physiological effects on brain activity remain unclear and debated. Here, we stimulated 60 DoC patients with the anode placed over left-dorsolateral prefrontal cortex in a prospective open-label study. Clinical behavioral assessment improved in twelve patients (20%) and none deteriorated. This behavioral response after tDCS coincided with an enhancement of putative EEG markers of consciousness: in comparison with non-responders, responders showed increases of power and long-range cortico-cortical functional connectivity in the theta-alpha band, and a larger and more sustained P300 suggesting improved conscious access to auditory novelty. The EEG changes correlated with electric fields strengths in prefrontal cortices, and no correlation was found on the scalp. Taken together, this prospective intervention in a large cohort of DoC patients strengthens the validity of the proposed EEG signatures of consciousness, and is suggestive of a direct causal effect of tDCS on consciousness.

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“…33 One more double-blind RCT included 26 patients with DOC (1-17 months postonset) who received 20 sessions of active or sham prefrontal tDCS over 10 days. 34 Clinical improvement was observed in the MCS group but not in the UWS group, combined with an increase in P300 amplitude for the responders. Finally, another RCT in 27 patients in MCS (10 months to 33 years post-injury) evaluated the effects of 20 sessions within 4 weeks of DLPFC tDCS applied by the patients' relatives or caregivers at home or in nursing homes.…”

Section: Transcranial Direct Current Stimulationmentioning

confidence: 89%

Therapeutic interventions in patients with prolonged disorders of consciousness

Thibaut

Schiff

Giacino

et al. 2019

The Lancet Neurology

289

229

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The management of patients with severe brain injuries and prolonged disorders of consciousness (DOC) raises important issues particularly with respect to their therapeutic options. The lack of treatment is challenged by new clinical and neuroimaging data indicating that some patients with prolonged DOC may benefit from therapeutic interventions, even years after the injury. The majority of the studies aiming at improving patients' level of consciousness and functional recovery includes behavioural and brain imaging open-label trials and case-reports, but several randomized clinical trials (RCT) have been conducted, especially using non-invasive brain stimulation. Only a couple of RCTs focused on the effects of drugs or sensory stimulation approaches, and only two Class II studies, on amantadine and transcranial direct current stimulation, have been published. While new therapeutic approaches seem to be valuable for patients with prolonged DOC, optimized stimulation parameters, alternative drugs or rehabilitation strategies still need to be tested and validated.

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Transcranial Direct Current Stimulation in Patients with Prolonged Disorders of Consciousness: Combined Behavioral and Event-Related Potential Evidence

Cited by 64 publications

References 44 publications

The clinical outcome of concurrent speech therapy and transcranial direct current stimulation in dysarthria and palilalia following traumatic brain injury: A case study

The clinical outcome of concurrent speech therapy and transcranial direct current stimulation in dysarthria and palilalia following traumatic brain injury: A case study

Combined behavioral and electrophysiological evidence for a direct cortical effect of prefrontal tDCS on disorders of consciousness

Therapeutic interventions in patients with prolonged disorders of consciousness

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