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Philip WilkinsonElectricity rendered useful?
Transcranial direct current stimulation for late life depression
Head Wrightson iron works
Richard Lovett
1756
Electricity rendered useful
Aims
Overview of tDCS in context of range of neurostimulatory therapies
Discussion of proposed use of tDCS in clinical setting
Discussion of clinical governance and ethical implications
Neurostimulatory treatments for depression
ECT Electroconvulsive therapy
VNS Vagus nerve stimulation
DBS Deep brain stimulation
rTMS Transcranial magnetic stimulation
tDCS Transcranial direct current stimulation
NeuroStarTMSTherapy - YouTube
Black Dog videos
Neurostimulatory treatments for depression
Cheap ? No need for anaesthesia ?
Non-invasive ? Portable ?
ECT
VNS
DBS
rTMS
tDCS
Neurostimulatory treatments for depression
Cheap No need for anaesthesia
Non-invasive Portable
ECT X X X X
VNS X X X X
DBS X X X X
rTMS X √ √ X
tDCS √ √ √ √
tDCS applications
Stroke
Parkinson’s disease
Migraine
Cognitive enhancement
Depression
"Depression is the most important psychiatric disorder in old age. With at least 20-30% not responding to standard treatments, the management of such patients is a science and a craft..."
Dr Hamish McAllister-Williams
Late life depression
Late-life depression is associated with more severe impairment in verbal learning and memory and motor speed than depression in earlier adult life and this is not due to ageing alone
Thomas AJ et al. Psychol Med. 2009;39(05):725-33.
Late life depression
White matter abnormalities in frontosubcortical and limbic networks play a key role even in the absence of changes in resting functional connectivity and grey matter
Sexton CE et al. Archives Gen Psychiatry.2012;69(7):680-9
SSRI resistance associated with white matter abnormalities in anterior cingulate, dorsolateral prefrontal cortex, etc.
Alexopoulos G. et al. Am J Psychiatry. 2008;165:238-44
White matter activation
TMS and ECT appear to increase prefrontal fractional anisotropy
Computer modelling of DLPFC tDCS suggests currents in distant limbic structures are comparable to stimulation current
Sadleir R. et al. Neuroimage. 2010;51:1310-8.
Cognitive effects of tDCS
Improvement in declarative and working memories after one session in healthy volunteers
Oliveira et al. Neurosci Lett. 2013;537(0):60-4
tDCS – possible mechanisms of action in depression
Increased neuronal excitability
Correction of right-left imbalance in DLPFC
Long-term neuroplastic effects via NMDA
Improved integrity of white matter tracts
GABAergic (enhanced learning after CVA)
Systematic review of tDCS trials in MDD
7 RCTs
259 participants
Mean age 44 years
Mean no. of previous antidepressant trials: 2.16
Shiozawa P et al. Int J Neuropsychopharm 2014 17(9) 1443-52
Systematic review of tDCS trials in MDD
Active tDCS superior to sham on continuous outcomes at study endpoint (g = 0.37; 95% CI 0.04-0.7)
Active tDCS superior to sham on response rates (OR 1.63; 95% CI 1.26-2.12)
Active tDCS superior to sham on remission rates (OR 2.5; 95% CI 1.26-2.49 )
Shiozawa P et al. Int J Neuropsychopharm 2014 17(9) 1443-52
Systematic review of tDCS trials in MDD
On meta-regression, no influence of baseline severity, treatment resistance, treatment parameters.
Shiozawa P et al. Int J Neuropsychopharm 2014 17(9) 1443-52
tDCS side-effectstingling (71%)
itching (30%)
headache (12%)
burning under the electrodes
difficulties in concentrating
acute mood changesBrunoni AR et al. Int J Neuropsychopharm, 2011
Aims of project
To make available to patients with poor prognosis depression an additional intervention
Assess acceptability and feasibility of the tDCS in a clinical setting
Use experience of intervention in design of future clinical trial ? home use device
Exclusion criteria
Requiring urgent ECT
Treatment with anticonvulsant or memantine
Cranial metallic implant
Cardiac pacemaker
Exclusion criteria
Dementia
Bipolar disorder
Unable to consent
tDCS parameters
30 minutes 2mA with 25cm2 electrodes and bifrontal montage (F3/F4)
Daily stimulations five days per week, up to four weeks.
Weekly taper stimulations, up to four weeks.
Pre and post-treatment
MÅDRS
MOCA
Working memory (n-back test)
CGI
n-back
Clinical monitoring
Standard nursing and medical review
Weekly MÅDRS
Weekly YMRS
Weekly AEQ
Innovative treatment or research?
‘This is a field marked by uncertainty and hype. Decisions taken by professionals and patients to use novel neurotechnologies must be based on the best available evidence of their benefits and risks.
Achieving this demands responsible communication that is open about the limits of our current understanding of efficacy and risk, while maintaining trust in these technologies.
It must also be underpinned by collaborative approaches to capitalise more effectively on existing evidence.’
Novel neurotechnologies: intervening in the brain
‘Three virtues in particular should guide actors across a wide range of settings and applications of novel neurotechnologies.
These virtues are inventiveness, humility and responsibility.’
Novel neurotechnologies: intervening in the brain
