It has been the subject of the study of researchers for several decades. However, current research does not support conclusive results about its efficacy. Nevertheless, neurofeedback is known as a complementary and alternative treatment of many brain dysfunctions. Also, it might take months to show the desired improvements. For example, it is expensive, time-consuming and its benefits are not long-lasting. Although it is a non-invasive procedure, its validity has been questioned in terms of conclusive scientific evidence. Neurofeedback, like other treatments, has its own pros and cons. To date, many studies have been conducted on the neurofeedback therapy and its effectiveness on the treatment of many diseases. treatment of attention deficit hyperactivity disorder, anxiety, depression, epilepsy, insomnia, drug addiction, schizophrenia, learning disabilities, dyslexia and dyscalculia, autistic spectrum disorders and so on as well as other applications such as pain management, and the improvement of musical and athletic performance and (6) Neurofeedback softwares. frequency, power, slow cortical potential, functional magnetic resonance imaging, and so on (5) Clinical applications of neurofeedback i.e. standard recording channels in the frontal, temporal, central, and occipital lobes (3) Electrode montages (unipolar, bipolar) (4) Types of neurofeedback i.e. alpha, beta, alpha/theta, delta, gamma, and theta (2) Different EEG electrode placements i.e. In this review, we provided clinical and technical information about the following issues: (1) Various neurofeedback treatment protocols i.e. Positive or negative feedback is produced for desirable or undesirable brain activities, respectively. Neurofeedback usually provides the audio and or video feedback. All three records were started at the same time.Neurofeedback is a kind of biofeedback, which teaches self-control of brain functions to subjects by measuring brain waves and providing a feedback signal. 元 The records of the variation with time of the vibrations produced by the earthquake as detected at the three laboratories are shown below. The laboratories are at the corners of a triangle so that each is separated from the others by a distance of 900 km, as shown in the diagram below. The waves from an earthquake close to the Earth’s surface are detected at three laboratories L 1, L2 and 元. Use the graph to determine the speed of (i) The graph below shows the variation with time t of the distance d moved by the two types of wave. The centre of an earthquake produces both longitudinal waves (P waves) and transverse waves (S waves). Explain why, in this situation, it is correct to refer to the “speed of the emitted light”, rather than its velocity.ĭefine, by reference to wave motion, what is meant by displacement .īy reference to displacement, describe the difference between a longitudinal wave and a transverse wave. (a)ĭefine what is meant by the speed of a wave. This question is about waves and wave motion. Using data from the above graph, deduce for this sound wave, (i) State whether this wave is an example of a longitudinal or a transverse wave. The variation of particle displacement with distance along the wave at one instant of time is shown below. A sound wave of frequency 660 Hz passes through air. Suggest what the area in c (iv) represents. (1)Įstimate the area between the curve and the x the x-axis -axis from the time t = t = 0 to the time t = t = 1.5 ms. Mark on the graph with the letter M one time at which the particle is at maximum displacement. (2)ĭetermine the frequency of oscillation of the particle. 8 6 4 2 vĮxplain how it can be deduced from the graph that the particle is oscillating. The graph below shows the variation with time t of t of the velocity v of one particle of the medium through which the wave is travelling. (3)īy taking appropriate measurements measurements from the diagram, determine the ratio of the speeds of the wave travelling from medium I to medium R. (1)Įxplain in which medium, I or R, the wave has the higher speed. On the diagram above, draw a line to complete the wavefront EF. Wavefront CD is shown crossing the boundary. The diagram below shows three wavefronts incident on a boundary between medium I and medium R. (a)īy making reference to waves, distinguish between a ray and a wavefront . This question is about waves and wave properties. NAME_ IB PHYSICS HL REVIEW PACKET: WAVES & VIBRATIONS 1.