BEST. BEST controlled. automated. Performance s Monitoring 28/05/2013. Neural signature of performance. Neural signature of performance

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1 Attualità e modelli di intervento in Psicologia dello sport Senigallia 27 Aprile 2013 Performance s Monitoring Ottimizzare la prestazione attraverso il e la tdcs Maurizio Bertollo BIND Center, G. D Annunzio University Chieti - Pescara Neural signature of performance Neural signature of performance 1. Progressive decrease in activation (more alpha) in the left hemisphere and more instability of activation in the right hemisphere. This decrease suggests less attention to stimuli, suppression of irrelevant information, and either use of an internal automatic pilot to guide performance or an intention to act 2. Progressive quieting of motor cortex (increased SMR )as an athlete becomes ready to perform. This may also be what results in the quiet eye findings (Vickers & Adolphe,1997) which showed eye movement fixation prior to good performance. 3. Task specific reduction in cerebral activation (more globalized low frequency alpha) is believed to be due to more efficient and task specific use of brain resources. Highly skilled athletes can perform the same tasks but more efficiently and with less effort. Two early studies have noted that athletes may show this lower activation level at rest. 4. Novice athletes, when compared to more skilled athletes, reduce occipital and left temporal / frontal alpha power and have concomitant heightened beta and gamma activity during movement. During target aiming,the assessment of task, skilled shooters show increased beta in the left hemisphere. They then shift gears to increase alpha,more of a quiet mind, for the actual performance. This increased alpha accompanied improved fine motor control in skilled athletes. 5. Sport training alone improved increases in alpha power at T3. 6. There is less coherence between Fz and T3 for alpha with better shooting performance and these changes are seen within hours and weeks. This decrease in coherence may be interpreted as signifying an increase in cerebral differentiation; whereby the athlete reduces activation in the area of the mind associated with talking through the movement (the verbal area) while keeping active the area of the cortex associated with performing the physical aspects of the task (motor strip). 7. Training to increase alpha in the left hemisphere resulted in an increase in shooting performance. 8. Different sports have different attentional patterns as reflected in the EEG 9. Enhancing SMR (13-15 Hz) while decreasing theta results in more calmness and focused attention. Enhancing Hz Beta (training) also improves some aspects of attention. 10.Cortical coherence Cz T3 with other electrodes 11.Cortical asimmetry related to performance: parietal and frontal Uni-dimensional within subjects performance comparison: Best vs Worst BEST BEST controlled Worst Worst automated Q2 Q3 Bi-dimensional within subjects performance comparison Q1 Q4 1

2 Cortical pattern within MAP Cortical pattern within MAP High alpha band Type 1 Type 2 Type 3 Type 4 Time (s) Future directions 0 1. Use MAP model to stay in the Zone 2. Apply MAP model to other sports Apply Multimodal and Multidimensional assessments and interventions in Sport Psy Develop integrated (with PST) biofeedback and neurofeedback interventions Define properly cortical areas to apply TMS and tdcs for perfomance improving From general and clinical setting to Sport psychophysiology Optimal Performance 2

3 Frequency Bands delta Hz theta 4-8 Hz alfa 8-12 Hz beta Hz gamma Hz Cortical Frequency Bands Hz Beta Broad band of beta. Used in theta/beta power ratios for ADHD evaluations Hz Sensorimotor Correlates with inhibition of motor output and sensory input combined rhythm (SMR) (C3, Cz, C4) with a mental state that maintains alertness and focus. A calm state, with decreased anxiety & impulsivity, and improved immune function Hz Beta Correlates with active problem solving and cognitive or motor activity. For most people conscious thinking/problem solving is associated with Hz activity. More beta is present when learning a task than when it is mastered Hz High Beta Correlates with emotional intensity (which may, in some cases be anxiety). Try too hard is often reported by athletes when in this state Hz High Beta Correlates with a busy brain. This can be related to cognitively processing many ideas or it may represent negative ruminating in some individuals. It may be the most important area of distraction in elite athletes. Elevated mid-20 s activity may correlate with family history of alcoholism /addiction. 40 Hz ( Sheer rhythm ) Gamma Sheer related this to attention and cognitive functioning a binding rhythm. Increasing it may help learning disabilities. A burst at 40 Hz occurs as one regains balance of a stabilometer Hz Range often monitored to reflect scalp, jaw and neck muscle activity. EMG inhibit range. (Use inhibit at Hz in,, ) 50 Hz Usually electrical interference. What is? is a technique of self-regulation by means of EEG-based biofeedback. In this technique, some current parameters of EEG recorded from a subject s scalp (such as an EEG power in a given frequency band) are presented to the subject through visual, auditory or tactile modality with the task to voluntarily alter these parameters in a desired (leading to a more efficient mode of brain functioning) direction. The position of electrodes and EEG parameters vary depending on the goals of neurofeedback. Altogether they define a so called protocol of neurofeedback. The other names: EEG-biofeedback, neuroregulation, neuronal regulation, EEG-based self regulation, neurotherapy How is performed? EEG amplifier is connected to the individual by two sensors placed on the scalp. The sensors are safe and painless; they do not prick the skin. The individual performs a task (which is not defined to him/her and which he/she has to assess) while receiving instant visual and auditory feedback on his/her theta, beta, SMR or other brainwave activity. The information is used to help individuals learn to change brainwaves to desired levels. 3

4 How long does take? is a training process where improvements take place over time. The effective treatment requires one-hour sessions. Learning to change brainwaves is similar to learning how to ride a bicycle. It takes a while to learn, but once it is learned it is never forgotten. Improvements in behavior are usually durable. A small percentage of individuals may need booster sessions. is based on three facts 1. The brain state (including any dysfunction or dys-regulation) is reflected in parameters of EEG recorded from the scalp. 2. The subject can voluntarily and selectively change some EEG parameters. 3. The human brain has plasticity to memorize the desired (rewarded) state. How the protocol may be chosen? At least two ways of choosing the protocol: 1. The protocol can be selected on the basis of QEEG assessment or on the basis of feedback from athletes. 2. Our model grows and changes over time. It is always tempting to look for the single measure that will tell us for sure how to train. I am quite sure such a measure does not exist. There is no formula here, only a powerful, flexible, and everchanging model. Bulldozer Principle of Activation and Relaxation protocols According to this principle the aim of neurofeedback is to normalize a pathologically abnormal EEG pattern. So, if there is an excess of some EEG parameter in a particular patient and in particular location in the cortex, the aim of the neurofeedback is to train this parameter DOWN, if there is a lack of some other EEG characteristi the corresponding neurofeedback parameter is trained UP. The method works like a bulldozer filling in the cavities and excavating the bumps. 4

5 Activation and relaxation protocols EEG frequencies for activation and relaxation protocols. A scheme represents relationship between metabolic activity and EEG power in different frequency bands. Note that in the alpha frequency band (8 12 Hz) the correlation is negative which defines the frequency parameter of relaxation protocols, while in the beta frequency band the correlation is positive which defines the frequency parameter of activation protocols. Relaxation protocols Relaxation Protocols Alpha (8 12 Hz) training is a common method used for many purposes. Taking into account that alpha rhythms are idling rhythms of the brain we can speculate that the neurofeedback protocols oriented to activate the alpha rhythms are relaxation protocols These protocols are intended to deactivate, inhibit the corresponding cortical areas. The relaxation training is often accompanied by presenting auditory stimuli, because visual stimuli activate and desynchronize the brain EEG in a larger extent than auditory stimuli PROTOCOL 1: SMR ENHANCEMENT/THETA SUPPRESSION This protocol is associated with the name of Barry Sterman. In his experiments with cats in 1960 he identified the Sensorimotor Rhythm (or SMR), which is generated over the Rolandic Cortex. Although initially identified as a range of activity between 12 and 20 cycles per second, the peak activity of the SMR was noted at Hz. He and his co-workers found that cats could be trained to produce this rhythm voluntarily and applied these findings in the treatment of individuals with a specific type of impaired behavioral control (epilepsy). As reviewed by Sterman (2000) and Monastra (2003), this application of EEG biofeedback has been demonstrated to be particularly helpful in the treatment of seizure disorders in patients who have not responded to pharmacological treatments The initial application of SMR training for the treatment of patients with ADHD was reported by Lubar and Shouse (1976). Their initial demonstration of clinical response in a hyperactive child stimulated considerable interest in SMR training as a potentially efficacious treatment for ADHD. Subsequently, in response to scientific understanding of the role of the frontal lobes in sustained attention, and mounting evidence of excessive cortical slowing over central, midline and frontal regions in ADHD patients, Lubar and his colleagues (e.g. Lubar & Lubar, 1984) expanded their EEG biofeedback treatments to include efforts to increase production of EEG activity in a faster Sport Specific Protocol: Attentional ability ratio of Theta power/beta power or (4-8 Hz)²/(13-21 Hz)² Lubar s theta power-beta power ratio is one measure that is used to establish the attentional ability of the athlete relative to a normative data base. The ratio reflects the capacity of the brain to be able to pay attention when needed. High ratios suggest an inability to attend (more theta). If there are serious deviations, 2 SD (Monastra et al, 2005), the athlete is retested and if the same reading is confirmed, the athlete is referred for assessment of attention deficit disorder. There are athletes who perform very well in sport who have been professionally diagnosed with clinically significant attention deficit disorders. When high scores occur, the athlete is given theta/beta training for enhancing attention. 5

6 PROTOCOL 2: SMR ENHANCEMENT- BETA-2 SUPPRESSION A secondary type of SMR training has also been examined in a controlled, group study (Fuchs, Birbaumer, Lutzenberger, Gruzelier, & Kaiser, 2003). In this protocol, patients with ADHD, Predominately Hyperactive-Impulsive Type are trained to increase SMR (12 15 Hz) activity, while simultaneously decreasing beta-2 (22 30 Hz) activity. Recordings are obtained at C4 with linked ear reference. Sampling rate is at least 128 Hz. In Fuchs et al. s protocol, patients with a Combined Type of ADHD receive this type of training during half of each session. During the other half of each session, a theta suppressionbeta- 1 enhancement protocol (described below) is followed (training site: C3). As with the first SMR protocol, feedback is contingent on patient success in controlling microvolts of theta, SMR, beta-1 or beta Sport Specific protocol: Busy Brain ratio of (26-34 Hz/13-15 Hz) Clinically adults report a large number of ideas, not necessarily negative, when they hould be calm and highly focused on the single task-at-hand. (Thompson 2006). A ratio greater than 1.55 can indicate that the individual is processing too much or experiencing a non-productive busy brain. Athletes typically report paralysis by analysis or over-thinking in their sports when this ratio is high. Additionally individuals tend to report doing a lot of self-evaluation, judgment, and rumination,especially under the stress of performance, which again, tends to distract from optimal performance. PROTOCOL 3: THETA SUPPRESSION/BETA-1 ENHANCEMENT This protocol has been investigated in three of the five controlled, group studies published to date (Linden, Habib, & Radojevic, 1996; Monastra, Monastra, & George, 2002; Rossiter & LaVaque, 1995). In this training procedure, patients are encouraged to increase production of beta-1 activity (16 20 Hz), while suppressing theta activity (4 8 Hz). Recordings are obtained at Cz with linked ear reference Feedback is provided contingent on patient success in controlling microvolts of beta or theta. A combination of two of these procedures (Protocol 1 and 3) has also been reported in a controlled, group study (Carmody, Radvanski,Wadhwani, Sabo, & Vergara, 2001). In this procedure, patients are encouraged to increase production of a restricted range of beta-1 activity (16 18 Hz) while suppressing activity at 2 7 Hz. Recordings are obtained at C3 or Cz with linked ear reference (monopolar). Students who displayed increased aggression or agitation within the first sessions of this type of training were considered to be overstimulated. Such patients were then treated with a SMR training protocol, in which they were reinforced for increasing activity at Hz and suppressing activity at 2 7 Hz. Sport Specific protocol Problem solving ratio of 6-10/11-12 Hz A second type of slow wave ratio includes high frequency theta and low frequency alpha which Dr Lubar called thalpha. Data on this ratio are being collected on individuals with attention deficit disorders and elite athletes but it requires further investigation and publications. Typically in adults and athletes the ratio is < 2 unless the individual is tuning out. Seldom do athletes score high in this area. Sport Specific protocol: Intensity ratio of Hz/11-12 Hz In clinical experience this ratio reflects important aspects of the mental state of athletes or executives who report having a high intensity or sometimes a try too hard response when performing. The clinician needs to ascertain whether anxiety is a possibility when the athlete ratio score is above 1.5. Clinicians must scrutinize the numeric values of both numerator and denominator of any ratio for a full understanding of what possibly may be causing this high ratio. It could be a sub-type of depression with anxiety or anxiety with agitation. These are experimental ratios and definitive conclusions can not be made. Limitations of neurofeedback 1. Needs for randomly controlled trials 2. The Bulldozer principle is not proved. We know mechanisms of training beta and alpha rhythms but we know nothing about why other abnormal rhythms must and can be suppressed. 3. It s time consuming procedure (up to 40 sessions). 4. It requires a lot of competence of the practitioner. It s easy to do neurofeedback wrong and difficult to do it right. 5. It needs an active involvement of the patient. As any learning procedure it depends very much on patient s motivation 6

7 tdcs in sport and exercise Definition A constant direct current (DC) (i.e. a flow of electric charge that does not change direction) polarizes, i.e. changes membrane potentials of cells. DC is applied to the brain by means of two electrodes: the one is an active electrode, localized on the dysfunctional site, and the other is a reference electrode, localized on some silent part of the body. The electric current is provided by a battery driven device. tdcs montage A central model of DC effect A, The setup using a mobile battery-operated direct current stimulator connected with 2 electrodes. One electrode (active) is positioned over C3 (corresponding to the precentral gyrus), and the reference electrode is positioned over the contralateral supraorbital region. If current flows from C3 to the supraorbital region, then the tissue underlying C3 is subjected to anodal (increase in excitability) stimulation. If current is reversed, then the tissue underlying C3 is subjected to cathodal (decrease in excitability) stimulation. B, Regional cerebral blood increases in the motor region underlying the electrode positioned over C3 after anodal stimulation. Regional cerebral blood was determined using a noninvasive arterial spin-labeling technique. (Schlaug et al., 2008) The central idea of how applied current affects neuronal activity is that it produces an extracellular voltage gradient which alters the potential difference across the membrane, with opposing polarities, at either end of the neuron. This induced transmembrane potential change causes current to flow across the membrane and along the inside of the neuron according to the resistances presented by the membrane and the intracellular space, which determine the length constant of the neuron. Electrotonically long neurons (i.e. with a short length constant) have changes in transmembrane potential restricted to the ends of the neurons; at other locations along such neurons, the changes in potential would be equal inside and out. Electrotonically short neurons, which probably are more typical of real mammalian brain, have a transmembrane potential change that varies linearly with distance along the axis of theapplied current. In real neurons, the effects of applied fields can be significantly more complex; for instance, the locations of bending and branching of dendrites and axons can have a major impact. Scheme of transcranial Direct Current Stimulation (tdcs). Electrophysiology of polarization induced by direct current Two electrodes are attached to the head. The electric current is provided by a battery driven device. The current usually does not exceed 1 ma while only a small part of it goes through the cortical grey matter. In the cortical layers the anodal current depolarizes pyramidal cells at their basal membrane. Two electrodes (positive and negative) on the scalp produce an electric current. A part of the electric current passes through the cortex. The current under the anode electrode induces a lack of positive ions at the basal part of neuronal membrane. This induces depolarization of this part of the membrane. The excitability of the neuron increases and the frequency of the background activity increases. The net effect is anodal activation of neurons. Vice versa, the current under the cathode electrode induces an excess of positive ions near the external part of the basal membrane. This induces hyperpolarization of this part of the membrane. The excitability of the neuron decreases and the frequency of the background activity decreases. The net effect is cathodal suppression of neurons. Hyperpolarization inactivates Ca and Na channels. Depolarization activates these channels. 7

8 Less that 10% of the current enters the cortex Longer aftereffects following 10 min tdcs Current density behavior through tissues.current density magnitude evaluated along an evaluation line in the healthy headmodel. The inset shows mesh model with the current density magnitude plotted on the surface of the cortex with the evaluation line shown intersecting the tissues the current density magnitudes displayed in the primary graph were calculated along this line. Note that the current density magnitude varies with the conductivity of the tissues. (Wagner, T., et al., Transcranial direct current stimulation: A computer-based human model study, NeuroImage (2007) Visual evoked potential P100 amplitude modulation induced by long-duration tdcs polarization (mean ± SD values of all subjects). The first VEP recording during tdcs started 1 min after polarization began. Black lines cathodal polarization, grey lines anodal polarization, thick lines high-contrast VEPs, dotted lines low contrast VEPs. *P <0.01 tdcs effects tdcs polarity effects in motor and cognitive domains: a meta-analytical review Transcranial direct current stimulation (tdcs) at low intensity induces changes in cortical excitability that are associated with depolarizatio/hyperpolarization processes on membrane. The effects of anodal and cathodal polarization are opponent and depend on many factors such as position of electrodes on the scalp, orientation of the cortical surface We do not know why effects of tdcs remain for long periods of time. They probably are associated with synaptic changes. 8