The health applications and clinical studies of meditation are products of the field of interest within the medical community to study the physiological effects of meditation.[1][2][3][4]
Meditation concepts have been applied to clinical settings in order to measure effects on somatic motor function as well as cardiovascular and respiratory function.[citation needed] Also the hermeneutic and phenomenological aspects of meditation are areas of growing interest. Meditation has entered the mainstream of health care as a method of stress and pain reduction.
As a method of stress reduction, meditation has been used in hospitals in cases of chronic or terminal illness to reduce complications associated with increased stress that include depressed immune systems. There is growing agreement in the medical community that mental factors such as stress significantly contribute to a lack of physical health, and there is a growing movement in mainstream science to fund research in this area. Dr. James Austin, a neurophysiologist at the University of Colorado, reported that meditation in Zen rewires the circuitry of the brain in his book Zen and the Brain (Austin, 1999). This has been confirmed using functional MRI imaging, a brain scanning technique that measures blood flow in the brain.[citation needed]
Dr. Herbert Benson of the Mind-Body Medical Institute, which is affiliated with Harvard and several Boston hospitals, reports that meditation induces a host of biochemical and physical changes in the body collectively referred to as the "relaxation response."[5] The relaxation response includes changes in metabolism, heart rate, respiration, blood pressure and brain chemistry. Benson and his team have also done clinical studies at Buddhist monasteries in the Himalayan Mountains.
Other studies within this field include the research of Jon Kabat-Zinn and his colleagues at the University of Massachusetts who have studied the effects of mindfulness meditation on stress.[6][7]
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A 2007 review article found no reliable effect of mindfulness meditation on anxiety or depression.[8] A 2006 article found "The strongest evidence for efficacy was found for epilepsy, symptoms of the premenstrual syndrome and menopausal symptoms. Benefit was also demonstrated for mood and anxiety disorders, autoimmune illness, and emotional disturbance in neoplastic disease." but noted also that "Clear and reproducible evidence supporting efficacy from large, methodologically sound studies is lacking."[9] A 2009 article found, "substantial disparity between what is espoused clinically and what is known empirically about the benefits of mindfulness practice".[10] Meditation was found to alleviate depressive symptoms in patients with fibromyalgia.[11] Participants enrolled in a 10-week mindfulness meditation program showed improved scores on test of depression and associated stress.[12]
Mindfulness meditation and related techniques are intended to train attention for the sake of provoking insight. A wider, more flexible attention span makes it easier to be aware of a situation, easier to be objective in emotionally or morally difficult situations, and easier to achieve a state of responsive, creative awareness or "flow".[13]
One theory, presented by Daniel Goleman & Tara Bennett-Goleman[14] suggests that meditation works because of the relationship between the amygdala and the prefrontal cortex.[15] In very simple terms, the amygdala is the part of the brain that decides if we should get angry or anxious (among other things), and the pre-frontal cortex is the part that makes us stop and think about things (it is also known as the inhibitory centre).
The prefrontal cortex is very good at analyzing and planning, but it takes a long time to make decisions. The amygdala, on the other hand, is simpler (and older [16] in evolutionary terms). It makes rapid judgments about a situation and has a powerful effect on our emotions and behaviour, linked to survival needs. For example, if a human sees a lion leaping out at them, the amygdala will trigger a fight or flight response long before the prefrontal cortex responds.
But in making snap judgments, our amygdalas are prone to error[citation needed], such as seeing danger where there is none. This is particularly true in contemporary society where social conflicts are far more common than encounters with predators, and a basically harmless but emotionally charged situation can trigger uncontrollable fear or anger — leading to conflict, anxiety, and stress.[17]
Because there is a gap between the time an event occurs and the time it takes the amygdala to react, a skilled meditator may be able to intervene before a fight or flight response takes over, and perhaps even redirect it into more constructive or positive feelings.[citation needed]
Studies done by Yale, Harvard, Massachusetts General Hospital have shown that meditation increases gray matter in the brain and slows down certain brain deterioration. The experiment included 20 individuals with intensive Buddhist "insight meditation" training and 15 who did not meditate. The brain scan revealed that those who meditated have an increased thickness of gray matter in parts of the brain that are responsible for attention and processing sensory input. The increase in thickness ranged between .004 and .008 inches (3.175 x 10−6m - 6.35 x 10 −6m) and was proportional to the amount of meditation. The study also showed that meditation helps slow down brain deterioration due to aging.[18][19]
Electroencephalograph (EEG) recordings of skilled meditators showed a significant rise in gamma wave activity in the 80 to 120 Hz range during meditation. There was also a rise in the range of 25 to 42 Hz. These meditators had 10 to 40 years of training in Buddhist-based mental training. EEG done on meditators who had received recent training demonstrated considerably less rise.[20]
The experienced meditators also showed increased gamma activity while at rest and not meditating.[20]
During meditation there is a modest increase in slow alpha or theta wave EEG activity.[20][21]
Chang and Lo found different results, explicable perhaps by the fact they show no sign of even having tested for gamma.[22] First they classify five patterns in meditation based on the normal four frequency ranges (delta < 4 Hz, theta 4 to <8Hz, alpha 8 to 13 Hz, and beta >13Hz). The five patterns they found were:
They found pattern #5 unique and characterized by:
They had collected EEG patterns from more than 50 meditators over the prior five years. Five meditation EEG scenarios are then described. They further state that most meditation is dominated by alpha waves. They found delta and theta waves occurred occasionally, sometimes while people fell asleep and sometimes not. In particular they found the amplitude suppressed pattern correlated with "the feeling of blessings."
O Nuallain,Sean (2009) [23] in Cognitive Sciences 4(2), is the first to interrelate the work on synchronized gamma in consciousness with the well-attested work on gamma in meditation in an experimental context. It adduces experimental and simulated data to show that what both have in common is the ability to put the brain into a state in which it is maximally sensitive and consumes power at a lower (or even zero)rate , briefly. It is argued that this may correspond to a “selfless” state and the more typical non-zero state, in which gamma is not so prominent, corresponds to a state of empirical self. Thus, the “zero power” in the title refers not only to the power spectrum of the brain as measured by the Hilbert transform, but also to a psychological state of personal renunciation.
Studies have shown that meditation has both short-term and long-term effects on various perceptual faculties.
In 1984, Brown et al. conducted a study that measured the absolute threshold of perception for light stimulus duration in practitioners and non-practitioners of mindfulness meditation. The results showed that meditators have a significantly lower detection threshold for light stimuli of short duration.[24]
In 2000, Tloczynski et al. studied the perception of visual illusions (the Müller-Lyer Illusion and the Poggendorff Illusion) by zen masters, novice meditators, and non-meditators. There were no statistically significant effects found for the Muler-Lyer illusion, however, there were for the Poggendorff. The zen masters experienced a statistically significant reduction in initial illusion (measured as error in millimeters) and a lower decrement in illusion for subsequent trials.[25]
The theory of mechanism behind the changes in perception that accompany mindfulness meditation is described thus by Tloczynski:
“A person who meditates consequently perceives objects more as directly experienced stimuli and less as concepts… With the removal or minimization of cognitive stimuli and generally increasing awareness, meditation can therefore influence both the quality (accuracy) and quantity (detection) of perception.”
Brown also points to this as a possible explanation of the phenomenon: “[the higher rate of detection of single light flashes] involves quieting some of the higher mental processes which normally obstruct the perception of subtle events.” In other words, the practice may temporarily or permanently alter some of the top-down processing involved in filtering subtle events usually deemed noise by the perceptual filters.
Both positive rewards and potential benefits of meditation have been noted in academic literature. However, according to a few sources, the practice of meditation is not free from side-effects [26][27]. Adverse effects have been reported, and may, in some cases, be the result of "improper use of meditation" [27]. That is, meditation may produce adverse effects in certain circumstances.
Among the side-effects that have been reported we find those mentioned by Craven [28]: uncomfortable kinaesthetic sensations, mild dissociation, feelings of guilt and, via anxiety-provoking phenomena, psychosis-like symptoms, grandiosity, elation, destructive behaviour and suicidal feelings [29]. From a clinical study of twenty-seven long term meditators, Shapiro [30] found that subjects reported significantly more positive effects than negative from meditation. However, of the twenty-seven subjects, seventeen (62.9%) reported at least one adverse effect, and two (7.4%) suffered profound adverse effects. Among these we find: relaxation-induced anxiety and panic; paradoxical increases in tension; less motivation in life; boredom; pain; impaired reality testing; confusion and disorientation; feeling 'spaced out'; depression; increased negativity; being more judgmental; and, ironically, feeling addicted to meditation [31].
In addition, the concept of meditation is sometimes associated with spiritual practices. Some of which may be characterized as "intensive". However, intensive spiritual practices, associated with Asian traditions, are problematic. Psychiatric literature [27] notes that: Since the influx of eastern spiritual practices and the rising popularity of meditation starting in the 1960s, many people have experienced a variety of psychological difficulties, either while engaged in intensive spiritual practice or spontaneously.
Particularly in the Chinese Qigong tradition, stories of unguided practitioners or inexpertly guided students developing chronic mental and physical health problems as a result of their attempts at meditation training are not uncommon. English speaking practitioners and teachers of Qigong and related disciplines note that the practice of this contemplative exercise is sometimes accompanied by physical and psychological distress[citation needed]. The identification of this syndrome has led to the inclusion of a culture-sensitive category in the DSM-IV called Qi-Gong Psychotic Reaction [32].
Meditative traditions which include the use of drugs are by some considered to be harmful to the practitioner. Additionally, as with any practice, meditation may also be used to avoid facing ongoing problems or emerging crises in the meditator's life. In such situations, it may be helpful to apply mindful attitudes acquired in meditation while actively engaging with current problems.[33]
At different times, some proponents have made extraordinary claims in favor of meditation. For example, in an early study in 1972, a paper claimed that Transcendental Meditation affected the human metabolism by lowering the biochemical byproducts of stress, such as lactate, decreasing heart rate and blood pressure and inducing favorable brain waves.[34] In 1976, the Australian psychiatrist Ainslie Meares reported the spontaneous regression of a single case of rectal cancer following intensive meditation. After writing about this uncontrolled case study involving a cancer known for occasional spontaneous regressions,[35] Meares would go on to write a number of books, including his best-seller Relief Without Drugs.[36]
Some modern methods of meditation, such as Transcendental Meditation,[37] discourage or disallow the use of mind-altering drugs. However, the use of stimulants has been proposed by some as a means to provide insight, and in some shamanistic traditions they are used as agents of ritual. Some Native American traditions emphasized the smoking of a pipe containing tobacco, salvia divinorum, or other plants. East Asian traditions use tea and Middle Eastern (and many Western) religions use coffee as an aid to meditation.[citation needed]
During the 1960s, eastern meditation traditions and psychedelics such as LSD became popular, and it was suggested that LSD use and meditation were both means to the same spiritual/existential end. Many practictioners of eastern traditions rejected this idea, including many who had tried LSD themselves. In The Master Game, Robert S de Ropp writes that the "door to full consciousness" can be glimpsed with the aid of substances, but to "pass beyond the door" requires yoga and meditation. Other authors, such as Rick Strassman, believe that the relationship between religious experiences reached by way of meditation and through the use of psychedelic drugs deserves further exploration.[38]
However, the fourth of the five precepts of the Pancasila, the ethical code in the Theravada and Mahayana Buddhist traditions states: "abstain from intoxicating drinks and drugs causing heedlessness." Edwin Arnold, in his famous poem The Light of Asia speaks of it like this: "Shun drugs and drinks which work the wit abuse; Clear minds, clean bodies, need no Soma juice."[39] Yoga texts also warns of the use of chemicals to alter consciousness.[40]
In June, 2007 the United States National Center for Complementary and Alternative Medicine published an independent, peer-reviewed, meta-analysis of the state of meditation research, conducted by researchers at the University of Alberta Evidence-based Practice Center. The report reviewed 813 studies involving five broad categories of meditation: mantra meditation, mindfulness meditation, yoga, Tai Chi, and Qi Gong, and included all studies on adults through September of 2005, with a particular focus on research pertaining to hypertension, cardiovascular disease, and substance abuse. The report concluded that "Many uncertainties surround the practice of meditation. Scientific research on meditation practices does not appear to have a common theoretical perspective and is characterized by poor methodological quality. Firm conclusions on the effects of meditation practices in healthcare cannot be drawn based on the available evidence. Future research on meditation practices must be more rigorous in the design and execution of studies and in the analysis and reporting of results."(p. 6) It noted that there is no theoretical explanation of health effects from meditation common to all meditation techniques.[42]
A further analysis of this data set in 2008 reaffirmed the weaknesses of the research, finding that "Most clinical trials on meditation practices are generally characterized by poor methodological quality with significant threats to validity in every major quality domain assessed". This was the conclusion despite a statistically significant increase in quality of all reviewed meditation research, in general, over time between 1956-2005. Of the 400 clinical studies, 10% were found to be good quality. A call was made for rigorous study of meditation.[43] These authors also noted that this finding is not unique to the area of meditation research and that the quality of reporting is a frequent problem in other areas of complementary and alternative medicine (CAM) research and related therapy research domains.
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