Transcranial Electrical Nerve Stimulation for Dementia
Overview[edit | edit source]
Transcranial electrical nerve stimulation (tES) or Cranial Electrical Nerve Stimulation, CES, is a non-invasive brain stimulation where brain activity is excited or inhibited by application of a low voltage constant or alternating currents to the human brain via scalp electrodes.
Image 1: tES administration. A subject (front) sits on a sofa relaxed, and a researcher (behind) controls the tDCS device (a). A head strap (d) for convenience and reproducibility, and also use a rubber band (e) for reducing resistance
tES is a promising tool in rehabilitation, based on the growing evidence that delivery of current to specific brain regions can promote desirable plastic changes. tES is becoming a topic for non-pharmacological management of various cognitive related conditions and this concept is still under research for effectiveness.
- tES and is one of the techniques used to stimulate the brain of a person with dementia.
- Recent evidence had shown that tES alone or in combination with physiotherapy improves certain functional activities in person with possible cognitive impairment
- tES is not a common practice among physiotherapists who are one of the experts in dementia management. Accordingly, this paper will provide information on the tES method of application to stimulate the brain of a person with dementia.
Dementia (Major Neurocognitive disorder)[edit | edit source]
Dementia is an impairment in one or more cognitive domains with impaired functional status, which is of concern to both patient and patient relative. Neuropsychological and behavioral characteristics such as anxiety, depression and sleep disturbances are prominent features of dementia.
Mechanism of Trans-cranial electrical nerve stimulation[edit | edit source]
Non-Invasive brain stimulation (trans-cranial electrical nerve stimulation ) main modalities is trancranial (direct and alternating) and this will be expansiate in this write up.
Other forms of non-invasive brain stimulation includes:
- Transcranial magnetic stimulation (TMS) - an electromagnet placed on the scalp generates magnetic field pulses that can activate axons and cause them to fire action potentials. For repetitive transcranial magnetic stimulation, it uses repeated application of TMS pulses for modulating brain activity.
- Repetitive transcranial magnetic stimulation,rTMS. - which uses repeated application of TMS pulses for modulating brain activity.
Transcranial electrical nerve stimulation (tES) stimulates or inhibit brain activity through use of two small electrodes placed on the head to deliver a constant low level of electric current. Forms of delivery:
- Transcranial alternating current stimulation, tACS, delivers an alternated sinusoidal current at a specific frequency. In tACS, specific sine-wave stimulation waveforms interact with endogenous brain oscillations to alter neuronal plasticity for desired outcome.
- Transcranial direct current stimulation,tDCS. The tDCS is believed to alter neuronal excitability by excitatory or inhibitory action and consequently modulatiing synaptic plasticity (long term potentiation or long term depression).
Cognitive Impairment Assessment[edit | edit source]
Evaluating a person with dementia requires neuropsychological assessment tools. Among these tools, the most common universally used is Mini Mental State Examination and for functional status, Functional Activities Questionnaire (FAQ) for older adults might be used. In addition, these tools can be used to monitor the progress of the intervention of a person with major neurocognitive impairment.
Trans-cranial Electrical Nerve Stimulation (CES) intervention[edit | edit source]
Scholars argued that tES could stimulate the brain and improve both cognitive impairment and neuropsychological characteristics of the dementia.
- The use of electrotherapy modalities such as tES requires a skin sensation test to determine whether the intervention is appropriate;
- The application of CES requires a number of parameters and this depend on the objectives to be achieved . Moreno-Duarte, argued that low-level tES is the most documented intensity level of tES application and four methods exist for this: transcranial direct current stimulation (tDCS), transcranial pulsed current stimulation (tPCS), transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS).
Although there is still some controversy regarding the use of tES among people with dementia, there is support for the evidence that the use of tES combined with/without physiotherapy improve cognitive, physical and behavioral characteristics of a person with dementia.
TES in Physiotherapy Practice for Brain Stimulation[edit | edit source]
Promising ﬁndings suggest that tDCS may be a useful stand alone treatment, or a useful complement to other physiotherapy treatments, in the management of chronic pain and neurological conditions.
- There are only a small numberof heterogeneous studies.
- Further large-scale trialsare needed using a range of tDCS parameters, long-term follow-up and different pathological popula-tions before clinical efﬁcacy can truly be determined.
- Note that although available research indicates that tDCS may be a useful clinical application for physiotherapists in future, the technique has not yet been approved for clinical use.
References[edit | edit source]
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