Clinical neuropsychology is a branch of psychology that deals with the diagnosis, evaluation and rehabilitation of patients with alterations in cognitive functions; the clinical neuropsychologist also deals with all emotional and behavioural aspects related to the different neurological conditions and the support of family members of patients with such pathologies.
It deals specifically with neurological patients with outcomes of cranial traumas, vascular diseases such as stroke, brain tumours, dementia, epilepsy, as well as a broad spectrum of developmental disorders such as attention deficits, cognitive delays, learning disorders, and autism. It also deals with any situation that has implications on the person’s cognitive functions, such as subjective memory disorders, concentration and attention issues in studies or daily working life.
Clinical neuropsychologists have a deep understanding of the central nervous system and its normal and pathological function; they use specific tools to evaluate individual cognitive abilities and intellectual abilities, and they create personalized treatments for the enhancement or rehabilitation of these, also using highly technological instruments such as transcranial Direct Current Stimulation (tDCS).
Several situations in which it may be useful to carry out a neuropsychological assessment or ask for a neuropsychologist’s consultation:
Transcranial Direct Current Stimulation (tDCS) is a non-invasive and painless procedure, without side effects, in which weak electrical currents (0.5-2 mA) are used to stimulate specific median brain areas used in cognitive processes. This technique, through the flow of current from one electrode to the other, modifies the membrane potential of neurons thus making the stimulated area more or less excitable. International scientific literature has shown that repetitive treatment with tDCS positively affects deficits by enhancing the effects of a classical rehabilitation without producing side effects and with significant benefits to a person’s quality of life.
Pathologies currently treated with tDCS:
Today, the study of the brain and its functions is progressing more and more thanks to neuroimaging techniques and brain stimulation and modulation. Disorders, due to degenerative or traumatic processes, strokes and neuropsychological processes, are now on the agenda especially due to the ageing of the population. Not only pharmacology but psychotherapy has proven capable of producing changes in the brain’s function. Understanding how this works and how to improve it is an important goal for interventions ranging from prevention to rehabilitation of specific and functional deficits. The tDCS (Transcranial Direct Current Stimulation) is an important resource in this process, given its modulation capability of cortical excitability with the absence of side effects.
The tDCS and its mechanisms
The tDCS, initially born in Italy and now used throughout the world, is a technique in which it is possible to stimulate different parts of the brain in a non-invasive, effective, painless way, and with no side effects. Although it is a relatively “new” technique, many studies indicate it is a valuable tool for the treatment of pathological conditions such as Parkinson’s disease, Alzheimer’s dementia, Multiple Sclerosis, chronic pain, addictions, post-stroke rehabilitation, traumas, depression, anxiety and in applications in Sports Medicine.
Stimulation with tDCS consists of a weak continuous electrical current of 1-2 mA, not perceptible by the subject, which is applied to the scalp via a couple of electrodes (one excitatory, the anode, and another inhibitor, the cathode) on a 35 cm² surface. The electrodes are coated with a synthetic sponge soaked in a saline solution to increase conductivity (allowing to cross the cranial bone and reach the cerebral area of interest) and avoid possible annoying effects caused by direct current application.
At this point they are inserted within a rubber cap (non-conductive) that makes it easier to fit over the head. Generally, a mounting is used where the active electrode is positioned on the area to be stimulated while the reference electrode is positioned on the elliptic orbital area or in a non-cephalic area (e.g. on the shoulder).
With the current from one electrode to the others, this technique modifies the neuron membrane potential by modulating the excitability of the cerebral cortex and hence the neuronal activity of a given part of the brain, by increasing or decreasing the functionality of the stimulated area (producing cognitive, behavioural and motor effects) for a period of time that persists beyond the duration of the stimulation. In particular, the anode stimulation depolarizes neurons by increasing the cortical excitability of the stimulated area, while cathode stimulation hyper-polarizes neurons with inhibitory effects. If the stimulation is repeated several times it is possible to make these changes more stable and long lasting (Bolognini et al. 2009).
The effects of tDCS vary on the variation of:
– Current density (ratio between current intensity and electrode size)
– Direction of current flow (from cathode to anode or anode to cathode)
– Duration of stimulation
– Neuronal geometry on which the stimulation works
– Characteristics of the stimulated neuronal tissue.
The modifications produced become more stable and long lasting (long-term effects) when the stimulation is repeated many times (Bolognini et al. 2009). The mechanisms underlying this stabilization of the effects could include the formation of new synapses by exploiting the long-term potentiation (LTP) and long-term depression (LTD) mechanisms. The glutamate system and the NMDA receptors seem to play an important role for these processes.
Currently, both at institutional research laboratories and at Institutes of the CIDIMU Group, the Transcranial Direct Current Stimulation technique is used for the following applications:
– Cognitive Rehabilitation
– Rehabilitation of motor impaired patients
– Rehabilitation of other nature and in athletes
ALL THIS BECAUSE THE BRAIN GOVERNS ALL BODY FUNCTIONS.