How do Binaural Beats Work
Active music therapy in the treatment of multiple sclerosis patients a matched control study. J Music Ther 2004 61 225-240. 2. Lengdobler H, Kiessling WR. Group music therapy in multiple sclerosis initial report of experience. Psychother Psychosom Med Psychol 1989 39 369-373. 3. Wiens ME, Reimer MA, Guyn HL. Music therapy as a treatment method for improving respiratory muscle strength in patients with advanced multiple sclerosis a pilot study. Rehabil Nurs 1999 24 74-80.
A summation of stimuli (e.g., binocular versus monocular vision, or binaural versus monaural hearing) increases the total stimulation in the same sensory modality, resulting in quicker RT. Different stimulus modalities, however, do not summate. When the RS consists of simultaneous visual and auditory stimuli, the RT is the same as that for the auditory stimulus alone, as the ear is a speedier stimulus transducer than the eye, and the energies of the visual and auditory signals do not summate in the brain.
Music therapy has undergone limited investigation in multiple sclerosis (MS). One study of 20 people with MS found that music therapy improved self-esteem, depression, and anxiety (1). Another study of 225 people with MS reported that group music therapy may provide psychological support, improve depression and anxiety, and assist in coping with the disease (2). In a small investigational study of people with advanced MS, an indication was noted that music therapy improves respiratory muscle weakness (3). In people with other conditions, music therapy has produced beneficial effects. Music therapy may have emotional and cognitive benefits. It has been shown to decrease anxiety in some, but not all, studies. Limited studies suggest that music therapy decreases agitation and aggression in people with Alzheimer's disease. Music also may improve cognitive function it may facilitate learning in children and college students and may improve attention and concentration in people with...
Figure 7.6 illustrates an audio front end for transduction of a soundstream into a string of multi-symbols, with a goal of carrying out ultra-high-accuracy speech transcription for a single speaker embedded in multiple interfering sound sources (often including other speakers). The description of this design does not concern itself with computational efficiency. Given a concrete design for such a system, there are many well-known signal-processing techniques for implementing approximately the same function, often orders of magnitude more efficiently. For the purpose of this introductory treatment (which, again, is aimed at illustrating the universality of confabulation as the mechanization of cognition), this audio front end design does not incorporate embellishments such as binaural audio imaging.
Binaural hearing is needed to identify the direction of sound waves and is based on the following two effects. (1) Sound waves that strike the ear obliquely reach the averted ear later than the other, resulting in a lag time. The change in direction that a normal human subject can just barely detect (direction threshold) is roughly 3 degrees. This angle delays the arrival of the sound waves in the averted ear by about 3 10-5 s ( B, left). (2) Sound reaching the averted ear is also perceived as being quieter differences as small as 1 dB can be distinguished. A lower sound pressure results in delayed firing of actions potentials, i.e., in increased latency ( B, right). Thus, the impulses from the averted ear reach the CNS later (nucleus accessorius, D5). Effects (1) and (2) are additive effects ( B). The external ear helps to decide whether the sound is coming from front or back, above or below. Binaural hearing also helps to distinguish a certain voice against high...
Inhibitory synapses contribute to neural processing in approximately equal numbers to synaptic excitation. Despite this, we are just now beginning to learn about their developmental plasticity. The development of one inhibitory projection nucleus in the auditory brainstem, called MNTB, has been relatively well studied. MNTB neurons are activated by the contralateral ear, and their axons project to auditory nuclei that encode binaural acoustic cues and contribute to sound localization. One of the postsynaptic targets to which MNTB projects to is the LSO (see schematic in Figure 8.28). The inhibitory terminals become refined in two phases during development, leading to a precise tonotopic map. During the first postnatal week, there is a large reduction of function contacts from the rat MNTB onto single LSO neurons. This was revealed by recording from individual LSO neuron while focally activating small areas within the MNTB. At birth, a 113 mm wide region of the MNTB functionally...
The presence of preimplant residual hearing has also been shown to have a positive effect on postimplant speech perception performance. Zwolan and colleagues48 compared the postoperative performance of 12 children who demonstrated some aided open-set speech recognition preimplant (the borderline candidacy group) with that of 12 matched controls who had no preimplant speech recognition (the traditional candidacy group). Candidacy for the study participation was based on preimplant binaural aided speech testing, and the children were subsequently implanted in their poorer hearing ear. Thus, mean preoperative audiograms did not differ for the implanted ears in the two groups. By 1 year postimplant, children in the borderline group had significantly higher scores than children in the traditional group on all six speech perception measures employed. Zwolan and colleagues suggested that increased auditory experience before implantation facilitated the development of speech perception skills...
Most otologic surgeons, even experienced ones, would agree that surgery for congenital aural atresia is challenging. Some submit that this procedure is inappropriate for unilateral cases, whereas others express no hesitation in recommending intervention to selected patients. The basis for this controversy has not been clearly articulated in the literature. In many cases, the bias has simply been inherited as part of the philosophy of one's training program. In order to provide more objectivity to this issue, several possible areas of concern need to be explored (1) impact of unilateral hearing loss, (2) probability of achieving binaural hearing with surgery and stability of hearing results over time, and (3) surgical risks, especially to the facial nerve. The purpose of this chapter is to analyze these issues and draw conclusions regarding surgery for the unilateral atretic ear. Both clinical and animal research have shown evidence of auditory brainstem abnormalities in the setting of...
The ear, of course, provides one of the five senses of the human body. The outer ear, consisting of the pinna and outer ear canal, is basically the sound gathering portion of anatomy. The input impedance at the entrance to the ear canal would be important for the acoustic load of earphones but is of little consequence for the consideration of, say, implantable middle ear devices. Our sense of directionality is dependent on differential arrival times at the outer ear, and the binaural difference in loudness and arrival time at the auditory cortex of the brain is the neurophysiological basis of determining directionality of sound.
As its name implies, music therapy uses music to facilitate healing. This type of therapy has been practiced for thousands of years. It was used in some form in ancient Egypt and ancient Greece. Singing and drumming are also components of shamanic and Native American healing. In the United States, music therapy degrees were first granted in the 1940s. The National Association for Music Therapy established music therapy as an official discipline in 1950. Conventional medicine has increasingly recognized music therapy. About 5,000 professional and student music therapists practice in the United States.
In music therapy, people either create or listen to music. The appropriate form of therapy for a specific person is determined by a trained music therapist. Music therapy may be practiced on an individual or group basis. Music is also sometimes used to facilitate imagery (see the chapter Hypnosis and Guided Imagery ). The mechanism by which music therapy may be therapeutic is not known. Music is known to produce emotional responses. Because the brain pathways for music-associated emotional responses are different from those for verbal communication, music may be a novel way to stimulate emotions, facilitate emotional processing, and produce emotional change. Some of music's benefits may be related to music-induced relaxation. In addition, for people with movement difficulties such as incoordination or walking disorders, music therapy may elicit entrainment, which essentially means that moving to the music makes movements more rhythmic, regular, and efficient.
Most patients undergoing atresia repair will have a residual conductive deficit of 10 dB. Sensorineural function should, therefore, be normal in order to maximize the potential for achieving binaural hearing. Normal or near-normal sen-sorineural function in the contralateral ear is also important to avoid operating on the better-hearing ear.
Older patients in whom mild presbycusis in the contralateral ear has begun to develop, or patients who suffer hearing loss in the normal ear, often seek surgical evaluation for correction. They realize how important binaural hearing is to them once the hearing becomes compromised in the normal ear. These patients, with favorable anatomy, are certainly candidates for atresiaplasty. Our oldest atresia patient was 61 years of age.
6The brain is able to combine two pure tones, each sent to a separate ear, to produce a beat tone at the difference frequency. Some researchers believe that this binaural beat effect can be exploited to affect brain states positively using difference frequencies related to those of the alpha, beta, and theta brainwaves. Even if it would be demonstrated that the brain can be trained to generate specific frequencies, whether or not altering the brainwaves has any effect on mind, body, or mood is subject to considerable debate.
Listening to the Binaural Beat
When you were a kid were you fascinated by those dog whistles that you could blow, not hear but all the dogs in the vicinity would come running? The high pitch was something that only they could here, and though it seemed the dogs didn't seem to arrive in droves as they did in the movies, it was enough for perhaps your pet dog to prick up his ears before sliding back into sleep.