By K. Mitch. University of Arkansas at Monticello.
The major cerebral activity associated with clinical and/or advantage of behavioural measures is their accessibil- experimentally induced pain buy cheap kamagra gold 100 mg. These imaging methods ity to investigators; that is discount 100mg kamagra gold with visa, they can be directly actually detect changes in regional cerebral blood ﬂow observed and quantiﬁed. This can be particularly use- (rCBF), which is closely related to synaptic activity. Moreover, both in scientiﬁc this chapter and readers are referred to Casey and and clinical arenas, concerns are frequently expressed Bushnell’s (2000) book Pain Imaging for more detailed over the complete reliance on patients’ self-reports information. Behavioural measures provide an additional able, though not always consistent, information source of data on which to base treatment decisions. For exam- Interestingly, pain behaviours and self-reported pain ple, some (but not all) clinical chronic pain conditions can provide conﬂicting information, presenting a have been associated with decreased resting thalamic dilemma for the clinician or scientist. It is important activation and many clinical pain states are character- to remember that pain behaviour, while more directly ized by increased activity in the anterior cingulate observable than self-report, is not necessarily a more cortex. These ﬁndings in clinical populations appear to valid or accurate measure of patients’ pain. In experimentally induced reported pain and overt pain behaviour diverge repre- cutaneous pain, activation in the thalamus, somato- sents an important clinical and scientiﬁc issue. The pattern of results appears to be Physiological and neurological measures inﬂuenced by: Physiological measures of pain have long been sought, as clinicians and scientists desired more 1 Temporal attributes (e. Obviously, response bias can sub- increased stimulus intensity, suggesting good corres- stantially affect the interpretation of pain assessment pondence between cerebral and perceptual responses. Brain imaging has also been used to examine endogen- While it is not possible to remove all sources of ous pain modulation. Elegant studies, using hypnotic response bias, several steps can be taken to reduce it: suggestions, have elucidated the neuroanatomical pathways involved in pain affect versus pain sensation. First, whether cerebral 2 Provide speciﬁc and detailed instructions to activation is ‘pain related’ is typically determined by patients regarding the use of the pain scales, for measuring rCBF in areas of interest during pain stimu- example in a practice trial ensure that the instruc- lation and subtracting out rCBF occurring during tions are understood by explicitly stating the end some control stimulation (typically an innocuous points of an NRS or VAS, for example 0 represents stimulus from the same modality). This approach ‘no pain’ and 10 represents the ‘most intense pain assumes that the only difference between the painful imaginable. It may may report high levels of clinical pain on an NRS, be these components of the pain condition, rather while behavioural observation reveals minimal than the pain itself, that produce increased activation pain behaviour. Furthermore, increased rCBF, multiple reasons, but response bias is one possible which reﬂects increased synaptic activity, could indi- explanation. In triangulation, patients Finally, these technologies remain quite expensive, rate their clinical pain and some experimental pain require highly specialized equipment and facilities stimulus using the same measurement scale, and demand considerable expertise. Therefore, their following which they are asked to match their clin- integration into routine clinical assessment is unlikely ical pain to the experimental pain stimulus. Nonetheless, pain imaging represents triangulating their responses, it is possible to a promising approach for translational pain research determine whether patients are using the pain and will undoubtedly expedite our understanding of scales consistently. The former Response bias refers to subjects’ ability to differentiate among stimuli of different intensity, while the latter refers Response bias is another important and vexing issue to the tendency to describe any stimulus as painful. Response bias refers to a gen- Thus, a direct measure that may reﬂect response eral phenomenon in which factors other than a bias is obtainable in experimental settings. While response bias is often assumed to refer to intentional misrepresenta- Key points tion of pain by the patient, it actually includes a wide range of factors. For example, errors in measurement • Pain measurement serves as the foundation for can result from patients not understanding how to use determining pain-related diagnoses and docu- the pain scale. Therefore, valid and the investigator or clinician on subjects’ pain responses reliable pain measures are vital. Moreover, patients • Pain measurement should accommodate the multi- may display unwitting, but systematic inaccuracies dimensional nature of pain, including assessment in reporting pain based on inﬂuences, such as of both the sensory and affective qualities of pain. PAIN MEASUREMENT IN HUMANS 77 • In addition to perceptual measures, assessment of Fillingim, R. Sex differences in analgesic behavioural and physiological pain responses can responses: evidence from experimental pain models. The assessment of pain neuroanatomical structures involved in the experi- behavior: implications for applied psychophysiology and ence of both clinical and experimental pain. Psychophysical measurement of normal • Response bias is a signiﬁcant concern in pain assess- and abnormal pain processing. Holdcroft A working knowledge of pain evaluation is critical, Self-report methods for because it serves to: assessing pain – history • Monitor the clinical condition over time. Self-reporting of pain is still the most reliable indica- • Analyse changes in response to treatment. This can be • Advance the principles and practice of pain achieved by means of a full pain history (Chapter 12) management. The particular method used will Moreover, The Joint Commission on Accreditation of depend upon both the patient and the scenario. A full Healthcare Organizations (JCAHO) set a standard in pain history and some of the multidimensional assess- 2000 for all healthcare organizations. Magill Pain Questionnaire (MPQ), patients have a right to appropriate assessment (and Descriptor Differential Scales (DDS)) are time con- management) of pain. As with all medical interactions, suming and will be inappropriate in a trauma patient such evaluation will involve history, examination and in acute, severe pain – at least until a measure of anal- appropriate special investigations.
The cosmogonic man must perceive the quality of the vibrations emitted by human organisms; the vibrations are of different frequen- cies buy discount kamagra gold 100 mg on-line, different wavelengths (thus different colors) depending on what part of the body is considered purchase 100mg kamagra gold mastercard. The genital area normally would vibrate in red, the belly in orange, the solar plexus in yellow, the heart in green, the throat in purple, the brain in blue, and above the head, one should "perceive" indigo. Man is like a great natural kaleiodoscope, and dis- ease, discomfort, would be translated by an ECK kinergist, as "a color 21 that doesn’t go well, or that vibrates in the wrong place". W hen the subject is vibrating on the nuance that suits him, his pulse is stronger; otherwise, it declines. The kinergist, who uses refer- 182 Medicine and Cults ences to the Chinese pulse, assigns a mark from 1 to 7 on a diagram, which becomes the subject’s energy morpho-psychogram. The ECK energetician-therapist’s job is thus to diagnose the flow of colors, to deduce from it any organic attacks or functional disorders, to propose appropriate treatments and to verify their effectiveness by seeing that the vibrations have returned to normal. To conduct the initial diagnosis, the expert takes with the pa- tient’s pulse with one hand, while passing a quartz prism over him with the other hand (no need to disrobe). The quartz enters into reso- nance with the patient’s vibrations that are felt via the pulse. ECK en- ergeticians believe that the pulse is slower if there is disharmony (and therefore a problem) at the place above which the prism is held, or on the contrary the pulse is stronger if all is well. In addition, taking the pulse is an essential part of the ECK energetician’s way of deciding on a prescription. For this, the patient holds a glass tube in his hand, with the proposed drug (homeopathic, antibiotic, or what have you). The expert notes the level of the pulse to see whether or not there is reso- nance. Patrick Véret also uses two tests, very spectacular when they are carried out by a group. The first test relates to three points — called ionic — located on the inner side of the foot, above the knee, and on the sternum. These points appear to be particularly sensitive to the ex- pert’s touch (to the point of eliciting cries of pain! The second test, "muscular testing" (on which Véret has no mo- nopoly), consists in testing the individual’s muscular resistance, a resis- tance that decreases considerably when he is holding on him an ele- 22 ment that disturbs his electromagnetic field. Each center is tested twice, first using a yin energy source, the second time with yang. This leads to the establishment of a diagram with two curves is: the first represents the person’s current experience, the second depicts his energy potential. In this view, food is consid- ered an optimal solution: all you have to do is get nutri-food marketed 23 by Cogego Laboratory, where Véret works as supervising doctor. ECK members and energetician-doctors regularly consume nutriments from organ meat, nutri-yin, nutri-yang, metals and amino acids that are supposed to restore their defective energy balances and to reunite them with the great primordial energy source. These products were studied at the behest of the national phar- macists’ organization. These products do not offer any protection, they contain extremely low amounts of nu- trients, the packaging provides no therapeutic indications, no in- 24 structions, and no true formula. The founder of ECK says, on the contrary, that eating nutri-food "allows the subject to elevate his vibratory level via his consciousness, through a practical and objective approach to the constant relation- ships between energy and the presentation of pathological symptoms". In his book, Introduction to Energy-Medicine, one can read: There is an energy-based way to approach the incidence of diabetes. It would be interesting to see which energy disorders might, at low vibrations, have induced this biological modification. In fact, it is a manifestation that corresponds to energy disorders that went untreated. It is hard to fight such absurdities when the promulgation of Chi- nese energy theories and homeo-energetic raving is accepted by the general public. ECK has managed to cobble together a set of doctrines based on 184 Medicine and Cults disparate elements from homeopathy spiced up with Tao (sprinkled with a bit of yin and yang), chromotherapy (the use of colors), biofeed- back and acupuncture. By using the traditional links of patamedicine, ECK was able to carve out its medical niche quickly and thus was able to recruit members in the medical and medical services milieu. In a 1992 study addressed to the [French] Association for the De- fense of Families and the Individual, the Health Ministry expressed the opinion of the National Academy of Medicine: Energo-medicine has no scientific basis. It is justified by no quantified data of a clinical, therapeu- tic or statistical nature. Its teaching cannot be authorized and its practical exercise does not appear to be compatible with the elemen- tary principles of medical-professional deontology. However, ECK’s founders do not stop at reinterpreting traditional energy medicine. ECK is not only an association with medical and an- cillary medical goals, it has created a structure where secrecy is the rule of operation. Admittedly, one might say that they need to keep their light under the bushel — so that it does not blind everyone — but in medical matters, since the Inquisition, medical works have been avail- able to all, with unrestricted access, and that is not the rule with ECK’s lessons: To you, student of the Energo-chromo-kinesis school,. This book will enable you to continue working on yourself, and that is why you have been given your own copy at the end of the session.
It is therefore very likely that any recording would be more a reflection of the electrical fields surrounding the equipment in the laboratory than of the physiological processes within the muscle of interest 100mg kamagra gold free shipping. To circum- vent the problem of choosing a sampling frequency that is too low safe kamagra gold 100mg, the theo- rem of Shannon is often used as a rule of thumb: The sampling frequency should be at least twice the highest frequency of interest. According to stan- dards prepared under the auspices of the International Society of Electro- physiological Kinesiology (ISEK), the range of signal frequencies for surface EMGs is from 1 to 3,000 Hz (Winter et al. In general, however, most of the power of the signal is in the range 50 to 150 Hz and certainly below 250 Hz (see Figure 4. For this reason a sampling frequency of 500 Hz would be more than adequate for surface EMG and will be within the capabilities of most data capturing systems presently in use. You can use needle or wire electrodes (Basmajian and DeLuca, 1985) and there are other possibilities, such as monopolar or bipolar surface electrodes. For a comprehensive review of these and other electrode types, refer to the texts by Loeb and Gans (1986) and Geddes (1972). The advantages of these electrodes are that they are simple to use, are noninvasive, and, if the skin surface is well prepared, will provide a good indication of the underlying muscle activity. Though in many applications in gait analysis this is not a problem, there are times when a deep muscle, such as tibialis posterior, may be suspected of some underlying pathology (such as spastic hemiplegia with a varus foot) and only deep, indwelling electrodes can be used. These electrodes are used more often to capture ECG (electrocar- diographic signals, but they also work well for EMG. A possible source of confusion here is that if the amplifier measures the difference between the two signals at its input stage, the need for a separate ground electrode is not that obvious. V V V2 The signals and1 2 are the input from the R2 electrodes placed on the muscle; the signal Vo R R 0 3 the output from the if = R1 R2 amplifier. R3 R then 0 [V - V ] V =o 2 1 R1 As mentioned earlier, one method for reducing motion artifact is to select electrodes such as the Ag/AgCl variety, which have low half-cell potentials. Another method of getting rid of most of these spurious signals is to take advantage of the fact that motion artifact noise is at the low end of the fre- quency spectrum (as seen in chapter 2, most gait signals repeat about once per second, i. By filtering out or removing any signals with a frequency less than 20 Hz, many of the problems caused by artifacts can be reduced. Also, as indicated previously, using a notch filter to eliminate 60 Hz background noise (sometimes referred to as mains hum) would be advis- able. Signal Processing Methods Some methods for processing EMG data have been recommended by ISEK (Winter et al. These include full-wave rectification, in which the absolute value of the signal is taken; a linear envelope detector, which consists of full-wave rectification fol- lowed by a low-pass filter (i. MUSCLE ACTIONS REVEALED THROUGH ELECTROMYOGRAPHY 52 Raw signal Rectified Figure 4. Notice Threshold that the threshold detection detector to determine if a muscle is on or off must Integrated be set arbitrarily. Voltage reset Time For the rest of this chapter, and in the software examples demonstrated in Chapter 5 and GaitLab, we have chosen to represent EMG signals processed by the linear envelope method. One of the fascinat- ing features of human gait, however, is that the central nervous system must control many muscles simultaneously. When you consider that this graph is for one side of the body only and that there is another set of muscles on the other side which are half a cycle out of phase, you realise just how complex the human locomotor apparatus is! This applies both to muscles with similar actions (such as tibialis anterior and extensor digitorum longus), as well as those with no immediately apparent connection (such as rectus femoris and gluteus maxi- mus). Wooden models of the pelvis and lower limbs were constructed and arranged in an expanded and sequential series depicting a single stride. Based on photographs of these models, drawings were made, and muscle groups were superimposed on the drawing of each model at each position. Then the level of the muscle activity was indicated by colour: red, highly active; pink, intermediate; and white, quiescent. The shading indicates the degree of activity: black, most active; stippled, intermediate; and white, quiescent. In addition, these muscle activity sequences have been colour-coded and animated in GaitLab. Tibialis posterior Adductor longus Adductor magnus Iliopsoas Sartorius Extensor digitorum longus Extensor hallucis longus Tibialis anterior Gracilis Semimembranosus Semitendinosus Biceps femoris (long) Biceps femoris (short) Stance phase Swing phase MUSCLE ACTIONS REVEALED THROUGH ELECTROMYOGRAPHY 54 Heel strike Foot flat Midstance Heel-off Figure 4. Toe-off Acceleration Midswing Deceleration Initial swing Preswing Midswing Terminal swing 55 DYNAMICS OF HUMAN GAIT A careful study of Figures 4. Most of the major muscle groups are active at or around both heel strike and toe-off (i. These are the periods of deceleration and acceleration of the legs, when body weight is transferred from one foot to the other. During midstance and midswing, most muscles (with the exception of gluteus medius and triceps surae during stance, and tibialis anterior during swing) are relatively quiescent. This is interesting because it is during these two periods (midstance and midswing) that the greatest observable movement takes place.