Recording the Rate of the Cranial Rhythmic Impulse
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《美国整骨期刊》
the Department of Osteopathic Manipulative Medicine, Midwestern University/Chicago College of Osteopathic Medicine in Downer's Grove, Ill.
The rate of the cranial rhythmic impulse can be obtained by both palpation and instrumentation. However, the literature has reported higher rates obtained by instrumentation compared with palpation. The cranial rhythmic impulse has been demonstrated to be synchronous with the Traube-Hering oscillation, measured in blood flow velocity. The current study demonstrates that physicians tend to palpate the cranial rhythmic impulse and Traube-Hering oscillation in a 1:2 ratio. This finding provides an explanation for the difference between palpated and instrumentally recorded rates for the cranial rhythmic impulse.
The most distinctive contribution that osteopathic medicine has made to contemporary medical practice is the diagnosis of somatic dysfunction and its therapy using osteopathic manipulative treatment (OMT).1 The techniques associated with osteopathy in the cranial field are possibly the most controversial forms of OMT.2,3 The core premise of cranial osteopathy, the primary respiratory mechanism, was first described more than 70 years ago.4 The primary respiratory mechanism is said to function in an oscillatory manner with inspiratory (flexion, external rotation) and expiratory (extension, internal rotation) phases. When palpated on the head, the primary respiratory mechanism is referred to as the cranial rhythmic impulse (CRI). Because of its low frequency and amplitude, the CRI is imperceptible to most untrained observers. Consequently, the sensitivity of palpation necessary to perform cranial diagnosis and manipulation, and the failure of its practitioners to demonstrate interrater reliability,3,5 has led many to question its validity. Yet, the topic is taught in all colleges of osteopathic medicine, and the American Osteopathic Association's textbook, Foundations for Osteopathic Medicine,6 devotes an entire chapter to it.
In our endeavors to objectively study cranial osteopathy, we have considered the CRI in the context of other known low-frequency oscillations in human physiology, such as blood flow velocity, also referred to as the Traube-Hering (TH) oscillation. We have demonstrated a statistically significant correlation between the palpated CRI and the 0.10 to 0.15 Hz TraubeHering (TH) oscillation measured by laser-Doppler flowmetry,7 and have further demonstrated that cranial manipulation specifically affects the TH rate.8,9 Moskalenko and Kravchenko10 reported that cranial manipulation exerts a comparable effect on similar-frequency oscillations (0.12–0.15 Hz) in intracranial fluid measured through transcranial bioimpedence.
The current study compares CRI rates obtained by laser-Doppler flowmetry with those obtained by palpation performed by osteopathic physicians skilled in cranial osteopathy. We sought to elucidate the common discrepancy in data obtained between the two methods when assessing interrater reliability in these measurements.
Methods
Palpation of the CRI by osteopathic physicians skilled in the methods of cranial osteopathy was compared with simultaneously recorded laser-Doppler flowmetry.
Participants
All subjects signed an informed consent form approved by the institutional review board of the Midwestern University/Chicago College of Osteopathic Medicine in Downer's Grove, Ill. Participants were recruited through a sign posted at the Osteopathic Diagnosis, Treatment and Education Service area at the American Osteopathic Association Convention, October 7 to 11, 2002, in Las Vegas, Nev, and at the American Academy of Osteopathy Convocation, March 19 to 23, 2002, in Norfolk, Va. All participants were volunteers, and each participant was used only once during the study.
Examiner participants were osteopathic physicians, and each was asked (1) "Can you palpate the CRI" and (2) "Would you be willing to compare palpation with laser-Doppler flowmetry" Each examiner palpated a different subject. Subject participants were osteopathic physicians and osteopathic medical students. Subjects tended to be younger individuals (<35 years) because such persons often demonstrate greater amplitude in the TH component of the flowmetry record,11-13 facilitating visual comparison between the concomitantly obtained flowmetry and palpation records.
In this study, no consideration was given to the presence or absence of specific dysfunctional cranial patterns in subjects. Because of the ubiquity of these findings, it was felt that such categorization would add an unnecessary layer of complexity to the study protocol and limit the availability of subjects.
Conditions and Protocol
The examinations were conducted in a quiet, curtained-off area (10 x 10 ft) in the Osteopathic Diagnosis, Treatment, and Educational Service provided by the American Academy of Osteopathy at the respective meetings. Before each examination, an adhesive flowmetry probe was attached to one of the subject's earlobes. Following this step, the subject lay quietly on the examination table. It was essential that the probe and leads were free of tension so that earlobe blood flow was not compromised. Relative blood flow velocities were measured by laser-Doppler flowmetry.7
Examiners were seated at the head of the examination table and were blinded to the flowmetry recordings. Using light touch,6 with hands in a contact position of their preference, examiners palpated their subject's CRI and enunciated the letter f to indicate a perception of the flexion/external rotation phase of the CRI, or the letter e to indicate a perception of the extension/internal rotation phase of the CRI, which was entered into the computer record by the recording technician (T.G.). Continuous recordings lasting 5 to 15 minutes were recorded for each examination, with the recording length determined by the examiner.
Laser-Doppler Flowmetry
The perfusion monitor determines the Doppler velocity change of the erythrocytes in circulating blood, and this measurement is digitized for subsequent data reduction. The device has an optic fiber probe that rests on the skin surface, causing no discomfort to the subject. The flowmeter, data reduction, and statistical methods used in this study have been described elsewhere.7
Results
The CRI rate was computed from the records of 44 different examiners, who each palpated a different subject. Flowmetry records were selected for analysis if they demonstrated a strong TH so that the relationships between the palpation events and the flowmetry readings were easily discernable. The portion of each record during which the CRI was palpated consistently, without large gaps in readings, was selected for this computation. The mean rate calculated for the palpated CRI was 4.54 cpm (range, 1.25–8.51 cpm). The SD was 2.08; SE, 0.313; and variance, 4.32.
Comment
Palpation vs Instrumentation
The palpated rate of the primary respiratory mechanism/CRI for normal adults was first reported in 1961 by Woods and Woods14 as 10 to 14 cpm, and this is the accepted rate described in most osteopathic medical textbooks.6,15–18 However, since then, studies documenting the rate of the CRI have reported lower rates obtained by palpation19–22 than by instrumentation23–26 (Figure 1). This discrepancy occurs independently of the method of instrumentation used. Upledger and Karni23 used plethysmography applied to the arm. This method is also used to record the TH.28–33 Zanakis et al24 measured the rate of motion of acupuncture needles implanted in the frontal and parietal bones of human subjects, monitoring reflected infrared light. Lockwood and Degenhardt25 analyzed data obtained by Fryman,27 who used a pressure transducer placed on the head. Moskalenko et al26 measured the fluctuation of intracranial fluid using transcranial electrical bioimpedance. The TH has also been demonstrated in intracranial fluid.34,35
The palpated rate of the CRI in the current study (4.54 cpm) is consistent with the lower rates obtained by palpation and reported by previous investigators.3,19,20,22 If instrumental measurement of the CRI is instead a measurement of the TH, then the discrepancy between the lower rate of palpated measurements and the higher instrumental measurements is explained. The inconsistency between palpation and instrumentation may also be explained by the observation that most examiners in the current study tended to palpate the CRI so that a flexion event was perceived coincident with one TH, and an extension event was perceived coincident with the next TH (Figure 2). (Palpation and flowmetry recordings, however, maintained a precise register.) This method resulted in a ratio of palpated CRI to recorded TH of 1:2.
The higher palpated rate (10–14 cpm) reported by Woods and Woods14 and identified in osteopathic medical textbooks5,14–18 is consistent with the rates obtained by instrumentation. It is worthwhile to note that, infrequently, an examiner will consistently palpate the CRI at a 1:1 ratio to the TH (Figure 3). The reason for this difference in palpation among individual examiners is unknown.
Interrater Reliability
During the recording process for this study, occasional irregularities were observed, resulting in gaps in both the palpatory and flowmetry records. These gaps, in some instances, were reported by the palpating examiners as still points (Figure 4), a phenomenon known in the practice of cranial manipulation.36 When calculating the rate of the CRI, it was necessary that we select the portion of each record where the CRI was palpated consistently, without large gaps between measurements that occurred when examiners had difficulty following the CRI in a continuous manner. In addition, two sets of researchers7,25 have noted that the CRI demonstrates a significant frequency modulation that causes the rate to vary rhythmically by approximately 20%.
The irregularity of the palpatory records, the presence of still points, and a frequency modulation of 20% in the rate of the CRI will all contribute to variability in the sequential palpatory records of two individuals tracking the CRI. Thus, sequential interrater reliability becomes virtually impossible to establish. This explanation addresses the inability to demonstrate interrater reliability between sequential examiners but not between two examiners palpating subjects at the same time.
Conclusion
Many low-frequency oscillations in the 6 to 9 cpm (0.1–0.15 Hz) range are found in the human body, such as blood pressure,28,29,31–33 blood flow velocity (TH),37 heart rate (R-to-R interval) variability,38 sympathetic tone in muscle,38 and intracranial fluid oscillations.34 These phenomena can be directly or indirectly linked to oscillations in the autonomic nervous system, particularly the sympathetic nervous system. The CRI, with reported rates ranging from 4 to 14 cpm (0.06–0.23 Hz), shares the spectral frequency band with these aforementioned physiologic oscillations. The CRI has been shown to correspond to the low-frequency TH in blood flow velocity.7 In addition, it has been demonstrated that manual cranial techniques affect TH8,9 and similar low-frequency oscillations in intracranial fluid.10 It is naive, however, to therefore draw the conclusion that these measurable phenomena are expressions of the primary respiratory mechanism or even the CRI. Rather, these phenomena offer points of access through which researchers may study the elusive aspects of cranial osteopathy.
Using such access with laser-Doppler flowmetry, we have provided insight into previously unexplained discrepancies in the reported rates of the CRI. In addition, by observing the relationship between the palpated CRI and TH, we have been able to offer possible explanations for difficulties encountered when attempting to sequentially compare palpated CRI rates to establish interrater reliability.
These studies represent only the beginning of the work that needs to be done. Although examiners palpating the CRI maintain precise register with blood flow oscillations measured instrumentally, we cannot explain why most of the osteopathic physicians we studied palpated the CRI/TH at a 1:2 rate, while a small number of osteopathic physicians palpated the CRI/TH at a 1:1 rate. This observation, plus the recognition of palpatory irregularities by examiners and a significant frequency modulation in the rhythm of the CRI provides possible insights into the illusiveness of positive interrater reliability studies. While the impact of cranial manipulation on the TH and the low-frequency oscillations in intracranial fluid have been previously demonstrated,8–10 the therapeutic value of these changes in fundamental physiology has, however, not yet been demonstrated. It is imperative that this work continue at multiple sites, by multiple researchers using as many different methods of instrumentation as possible if researchers are to answer the questions posed above and quantify the contribution that cranial osteopathy brings to the practice of osteopathic medicine.
References
1. Peppin JF. The osteopathic distinction: fact or fancy. J Med Humanities. 1993;14:203 –222.
2. Ferré JC, Barbin JY. The osteopathic cranial concept: fact or fiction Surg Radiol Anat.1991; 13:165 –170.
3. Hartman SE, Norton JM. Interexaminer reliability and cranial osteopathy. Sci Rev Altern Med.2002; 6:23 –34.
4. Sutherland WG. The Cranial Bowl. Mankato, Minn: Free Press Co; 1939, reprinted, 1986.
5. Wirth-Pattullo V, Hayes KW. Interrater reliability of craniosacral rate measurements and their relationship with subjects' and examiners' heart and respiratory rate measurements. Physical Therapy.1994; 74:908 –916.
6. King HH, Lay EM. Osteopathy in the cranial field. In: Ward RC, ed. Foundations for Osteopathic Medicine. 2nd ed. Baltimore, Md: Lippincott Williams & Wilkins; 2003:985 –1001.
7. Nelson KE, Sergueef N, Lipinski CL, Chapman A, Glonek T. The cranial rhythmic impulse related to the Traube-Hering-Mayer oscillation: comparing laser-Doppler flowmetry and palpation. J Am Osteopath Assoc. 2001;101:163 –173.
8. Sergueef N, Nelson KE, Glonek T. The effect of cranial manipulation upon the Traube Hering Meyer oscillation. Alternative Therapies in Health and Medicine. 2002;8:74 –76.
9. Nelson KE, Sergueef N, Glonek T. Cranial manipulation induces sequential changes in blood flow velocity on demand. Amer Acad Osteopath J. 2004;14:15 -17.
10. Moskalenko YE, Kravchenko TI. Wave phenomena in movements of intracranial liquid media and the primary respiratory mechanism. Amer Acad Osteopath J.2004; 14:29 –40.
11. Gribben B, Pickering TG, Sleight P, Peto R. Effect of age and high blood pressure on baroreflex sensitivity in man. Circ Res. 1971;29:424 –431.
12. O'Brian IAD, O'Hare P, Corrall RJM. Heart rate variability in healthy subjects: effect of age and the derivation of normal ranges for tests of autonomic function. Br Heart J.1986; 55:348 –354.
13. Matsukawa T, Sugiyama Y, Watanabe T, Kobayashi F, Mano T. Baroreflex control of muscle sympathetic nerve activity is attenuated in the elderly. J Auton Nerv Syst.1998; 73:182 –185.
14. Woods JM, Woods RH. A physical finding relating to psychiatric disorders. J Am Osteopath Assoc.1961; 60:988 –993.
15. Magoun HI. Osteopathy in the Cranial Field. 2nd ed. Kirksville, Mo: The Journal Printing Company;1966 .
16. Upledger JE, Vredevoogd JD. Craniosacral Therapy. Chicago, Ill: Eastland Press;1983 .
17. Sergueef N. Le B.A.BA du Cranien. 3rd ed. Paris, France: Spek; 2000.
18. DiGiovanna E, Schiowitz S, eds. An Osteopathic Approach to Diagnosis and Treatment. 2nd ed. Philadelphia, Pa: JB Lippincott Raven Co; 1997.
19. Fernandez D, Lecine A. L'enregistrement de l'onde de Traube-Hering et de la palpation cranienne simultanee. Kinesitherapie Scientifique. 1990;292:33 –40.
20. Norton JM, Sibley G, Broder-Oldach R. Characterization of the cranial rhythmic impulse in healthy human adults. Amer Acad Osteopath J. 1992;2:9 –12,26.
21. McAdoo J, Kuchera ML. Reliability of cranial rhythmic impulse palpation . J Am Osteopath Assoc.1995; 95:491 .
22. Hanten WP, Dawson DD, Iwata M, Seiden M, Whitten FG, Zink T. Craniosacral rhythm: reliability and relationships with cardiac and respiratory rates. J Orthop Sports Phys Ther.1998; 27:213 –218.
23. Upledger JE, Karni Z. Strain plethysmography and the cranial rhythm. Proc XII Internat Conf Med Biol Eng. Jerusalem, Israel; Aug 19–24,1979; Part IV: 69.5.
24. Zanakis MF, Cebelenski RM, Dowling D, Lewandoski MA, Lauder CT, Kirchner KT, et al. The cranial kinetogram: objective quantification of cranial mobility in man . J Am Osteopath Assoc. 1994;94:761 .
25. Lockwood MD, Degenhardt BF. Cycle-to-cycle variability attributed to the primary respiratory mechanism. J Am Osteopath Assoc. 1998;98:35 –43.
26. Moskalenko YE, Kravchenko TI, Gaidar BV, Vainshtein GB, Semernya VN, Maiorova NF, et al. Periodic mobility of cranial bones in humans. Human Physiol.1999; 25:62 –70.
27. Fryman VM. A study of the rhythmic motions of the living cranium. JAm Osteopath Assoc.1971; 70:928 –945.
28. Traube L. Ueber periodische Thtigkeits-Aeusserungen des vasomotorischen und Hemmungs-Nervenzentrums. Cbl Med Wissl. 1865;56:881 –885.
29. Hering E. über Athembewegungen des Gefsystems. Sitz Ber Akad Wiss Wien Mathe-Naturwiss Kl Anatl.1869; 60:829 –856.
30. Mayer S. über spontane Blutdruckschwankungen. Sitz Ber Akad Wiss Wien Mathe-Naturwiss Kl Anatl.1876; 67:281 –305.
31. Peáz J. Mayer waves: history and methodology. Automedical.1978; 2:135 –141.
32. Hyndman BW. The role of rhythms in homeostasis. Kybernetikl.1974; 15:227 –236.
33. Akselrod S, Gordon D, Madwed JB, Snidman NC, Shannon DC, Cohen RJ. Hemodynamic regulation: investigation by spectral analysis. Am J Physiol. 1985;249:H867 –H875.
34. White DN. The early development of neurosonology, III: pulsatile echoencephalography and Doppler techniques. Ultrasound Med Biol. 1992;18:323 –376.
35. Clarke MJ, Lin JC. Microwave sensing of increased intracranial water content. Invest Radiol.1983; 18:245 –248.
36. Glossary of osteopathic terminology. In: Ward RC, ed. Foundations for Osteopathic Medicine. 2nd ed. Baltimore, Md: Williams & Wilkins; 2003:1251 .
37. Mevio E, Bernardi L. Phasic changes in human nasal and skin blood flow: relationship with autonomic tone. Ann Otol Rhinol Laryngol. 1994;103:789 –795.
38. Saul PJ, Rea RF, Eckberg DL, Berger RD, Cohen RJ. Heart rate and muscle sympathetic nerve variability during reflex changes of autonomic activity. Am J Physiol.1990; 258:H713 –H721.(Kenneth E. Nelson, DO; Ni)
The rate of the cranial rhythmic impulse can be obtained by both palpation and instrumentation. However, the literature has reported higher rates obtained by instrumentation compared with palpation. The cranial rhythmic impulse has been demonstrated to be synchronous with the Traube-Hering oscillation, measured in blood flow velocity. The current study demonstrates that physicians tend to palpate the cranial rhythmic impulse and Traube-Hering oscillation in a 1:2 ratio. This finding provides an explanation for the difference between palpated and instrumentally recorded rates for the cranial rhythmic impulse.
The most distinctive contribution that osteopathic medicine has made to contemporary medical practice is the diagnosis of somatic dysfunction and its therapy using osteopathic manipulative treatment (OMT).1 The techniques associated with osteopathy in the cranial field are possibly the most controversial forms of OMT.2,3 The core premise of cranial osteopathy, the primary respiratory mechanism, was first described more than 70 years ago.4 The primary respiratory mechanism is said to function in an oscillatory manner with inspiratory (flexion, external rotation) and expiratory (extension, internal rotation) phases. When palpated on the head, the primary respiratory mechanism is referred to as the cranial rhythmic impulse (CRI). Because of its low frequency and amplitude, the CRI is imperceptible to most untrained observers. Consequently, the sensitivity of palpation necessary to perform cranial diagnosis and manipulation, and the failure of its practitioners to demonstrate interrater reliability,3,5 has led many to question its validity. Yet, the topic is taught in all colleges of osteopathic medicine, and the American Osteopathic Association's textbook, Foundations for Osteopathic Medicine,6 devotes an entire chapter to it.
In our endeavors to objectively study cranial osteopathy, we have considered the CRI in the context of other known low-frequency oscillations in human physiology, such as blood flow velocity, also referred to as the Traube-Hering (TH) oscillation. We have demonstrated a statistically significant correlation between the palpated CRI and the 0.10 to 0.15 Hz TraubeHering (TH) oscillation measured by laser-Doppler flowmetry,7 and have further demonstrated that cranial manipulation specifically affects the TH rate.8,9 Moskalenko and Kravchenko10 reported that cranial manipulation exerts a comparable effect on similar-frequency oscillations (0.12–0.15 Hz) in intracranial fluid measured through transcranial bioimpedence.
The current study compares CRI rates obtained by laser-Doppler flowmetry with those obtained by palpation performed by osteopathic physicians skilled in cranial osteopathy. We sought to elucidate the common discrepancy in data obtained between the two methods when assessing interrater reliability in these measurements.
Methods
Palpation of the CRI by osteopathic physicians skilled in the methods of cranial osteopathy was compared with simultaneously recorded laser-Doppler flowmetry.
Participants
All subjects signed an informed consent form approved by the institutional review board of the Midwestern University/Chicago College of Osteopathic Medicine in Downer's Grove, Ill. Participants were recruited through a sign posted at the Osteopathic Diagnosis, Treatment and Education Service area at the American Osteopathic Association Convention, October 7 to 11, 2002, in Las Vegas, Nev, and at the American Academy of Osteopathy Convocation, March 19 to 23, 2002, in Norfolk, Va. All participants were volunteers, and each participant was used only once during the study.
Examiner participants were osteopathic physicians, and each was asked (1) "Can you palpate the CRI" and (2) "Would you be willing to compare palpation with laser-Doppler flowmetry" Each examiner palpated a different subject. Subject participants were osteopathic physicians and osteopathic medical students. Subjects tended to be younger individuals (<35 years) because such persons often demonstrate greater amplitude in the TH component of the flowmetry record,11-13 facilitating visual comparison between the concomitantly obtained flowmetry and palpation records.
In this study, no consideration was given to the presence or absence of specific dysfunctional cranial patterns in subjects. Because of the ubiquity of these findings, it was felt that such categorization would add an unnecessary layer of complexity to the study protocol and limit the availability of subjects.
Conditions and Protocol
The examinations were conducted in a quiet, curtained-off area (10 x 10 ft) in the Osteopathic Diagnosis, Treatment, and Educational Service provided by the American Academy of Osteopathy at the respective meetings. Before each examination, an adhesive flowmetry probe was attached to one of the subject's earlobes. Following this step, the subject lay quietly on the examination table. It was essential that the probe and leads were free of tension so that earlobe blood flow was not compromised. Relative blood flow velocities were measured by laser-Doppler flowmetry.7
Examiners were seated at the head of the examination table and were blinded to the flowmetry recordings. Using light touch,6 with hands in a contact position of their preference, examiners palpated their subject's CRI and enunciated the letter f to indicate a perception of the flexion/external rotation phase of the CRI, or the letter e to indicate a perception of the extension/internal rotation phase of the CRI, which was entered into the computer record by the recording technician (T.G.). Continuous recordings lasting 5 to 15 minutes were recorded for each examination, with the recording length determined by the examiner.
Laser-Doppler Flowmetry
The perfusion monitor determines the Doppler velocity change of the erythrocytes in circulating blood, and this measurement is digitized for subsequent data reduction. The device has an optic fiber probe that rests on the skin surface, causing no discomfort to the subject. The flowmeter, data reduction, and statistical methods used in this study have been described elsewhere.7
Results
The CRI rate was computed from the records of 44 different examiners, who each palpated a different subject. Flowmetry records were selected for analysis if they demonstrated a strong TH so that the relationships between the palpation events and the flowmetry readings were easily discernable. The portion of each record during which the CRI was palpated consistently, without large gaps in readings, was selected for this computation. The mean rate calculated for the palpated CRI was 4.54 cpm (range, 1.25–8.51 cpm). The SD was 2.08; SE, 0.313; and variance, 4.32.
Comment
Palpation vs Instrumentation
The palpated rate of the primary respiratory mechanism/CRI for normal adults was first reported in 1961 by Woods and Woods14 as 10 to 14 cpm, and this is the accepted rate described in most osteopathic medical textbooks.6,15–18 However, since then, studies documenting the rate of the CRI have reported lower rates obtained by palpation19–22 than by instrumentation23–26 (Figure 1). This discrepancy occurs independently of the method of instrumentation used. Upledger and Karni23 used plethysmography applied to the arm. This method is also used to record the TH.28–33 Zanakis et al24 measured the rate of motion of acupuncture needles implanted in the frontal and parietal bones of human subjects, monitoring reflected infrared light. Lockwood and Degenhardt25 analyzed data obtained by Fryman,27 who used a pressure transducer placed on the head. Moskalenko et al26 measured the fluctuation of intracranial fluid using transcranial electrical bioimpedance. The TH has also been demonstrated in intracranial fluid.34,35
The palpated rate of the CRI in the current study (4.54 cpm) is consistent with the lower rates obtained by palpation and reported by previous investigators.3,19,20,22 If instrumental measurement of the CRI is instead a measurement of the TH, then the discrepancy between the lower rate of palpated measurements and the higher instrumental measurements is explained. The inconsistency between palpation and instrumentation may also be explained by the observation that most examiners in the current study tended to palpate the CRI so that a flexion event was perceived coincident with one TH, and an extension event was perceived coincident with the next TH (Figure 2). (Palpation and flowmetry recordings, however, maintained a precise register.) This method resulted in a ratio of palpated CRI to recorded TH of 1:2.
The higher palpated rate (10–14 cpm) reported by Woods and Woods14 and identified in osteopathic medical textbooks5,14–18 is consistent with the rates obtained by instrumentation. It is worthwhile to note that, infrequently, an examiner will consistently palpate the CRI at a 1:1 ratio to the TH (Figure 3). The reason for this difference in palpation among individual examiners is unknown.
Interrater Reliability
During the recording process for this study, occasional irregularities were observed, resulting in gaps in both the palpatory and flowmetry records. These gaps, in some instances, were reported by the palpating examiners as still points (Figure 4), a phenomenon known in the practice of cranial manipulation.36 When calculating the rate of the CRI, it was necessary that we select the portion of each record where the CRI was palpated consistently, without large gaps between measurements that occurred when examiners had difficulty following the CRI in a continuous manner. In addition, two sets of researchers7,25 have noted that the CRI demonstrates a significant frequency modulation that causes the rate to vary rhythmically by approximately 20%.
The irregularity of the palpatory records, the presence of still points, and a frequency modulation of 20% in the rate of the CRI will all contribute to variability in the sequential palpatory records of two individuals tracking the CRI. Thus, sequential interrater reliability becomes virtually impossible to establish. This explanation addresses the inability to demonstrate interrater reliability between sequential examiners but not between two examiners palpating subjects at the same time.
Conclusion
Many low-frequency oscillations in the 6 to 9 cpm (0.1–0.15 Hz) range are found in the human body, such as blood pressure,28,29,31–33 blood flow velocity (TH),37 heart rate (R-to-R interval) variability,38 sympathetic tone in muscle,38 and intracranial fluid oscillations.34 These phenomena can be directly or indirectly linked to oscillations in the autonomic nervous system, particularly the sympathetic nervous system. The CRI, with reported rates ranging from 4 to 14 cpm (0.06–0.23 Hz), shares the spectral frequency band with these aforementioned physiologic oscillations. The CRI has been shown to correspond to the low-frequency TH in blood flow velocity.7 In addition, it has been demonstrated that manual cranial techniques affect TH8,9 and similar low-frequency oscillations in intracranial fluid.10 It is naive, however, to therefore draw the conclusion that these measurable phenomena are expressions of the primary respiratory mechanism or even the CRI. Rather, these phenomena offer points of access through which researchers may study the elusive aspects of cranial osteopathy.
Using such access with laser-Doppler flowmetry, we have provided insight into previously unexplained discrepancies in the reported rates of the CRI. In addition, by observing the relationship between the palpated CRI and TH, we have been able to offer possible explanations for difficulties encountered when attempting to sequentially compare palpated CRI rates to establish interrater reliability.
These studies represent only the beginning of the work that needs to be done. Although examiners palpating the CRI maintain precise register with blood flow oscillations measured instrumentally, we cannot explain why most of the osteopathic physicians we studied palpated the CRI/TH at a 1:2 rate, while a small number of osteopathic physicians palpated the CRI/TH at a 1:1 rate. This observation, plus the recognition of palpatory irregularities by examiners and a significant frequency modulation in the rhythm of the CRI provides possible insights into the illusiveness of positive interrater reliability studies. While the impact of cranial manipulation on the TH and the low-frequency oscillations in intracranial fluid have been previously demonstrated,8–10 the therapeutic value of these changes in fundamental physiology has, however, not yet been demonstrated. It is imperative that this work continue at multiple sites, by multiple researchers using as many different methods of instrumentation as possible if researchers are to answer the questions posed above and quantify the contribution that cranial osteopathy brings to the practice of osteopathic medicine.
References
1. Peppin JF. The osteopathic distinction: fact or fancy. J Med Humanities. 1993;14:203 –222.
2. Ferré JC, Barbin JY. The osteopathic cranial concept: fact or fiction Surg Radiol Anat.1991; 13:165 –170.
3. Hartman SE, Norton JM. Interexaminer reliability and cranial osteopathy. Sci Rev Altern Med.2002; 6:23 –34.
4. Sutherland WG. The Cranial Bowl. Mankato, Minn: Free Press Co; 1939, reprinted, 1986.
5. Wirth-Pattullo V, Hayes KW. Interrater reliability of craniosacral rate measurements and their relationship with subjects' and examiners' heart and respiratory rate measurements. Physical Therapy.1994; 74:908 –916.
6. King HH, Lay EM. Osteopathy in the cranial field. In: Ward RC, ed. Foundations for Osteopathic Medicine. 2nd ed. Baltimore, Md: Lippincott Williams & Wilkins; 2003:985 –1001.
7. Nelson KE, Sergueef N, Lipinski CL, Chapman A, Glonek T. The cranial rhythmic impulse related to the Traube-Hering-Mayer oscillation: comparing laser-Doppler flowmetry and palpation. J Am Osteopath Assoc. 2001;101:163 –173.
8. Sergueef N, Nelson KE, Glonek T. The effect of cranial manipulation upon the Traube Hering Meyer oscillation. Alternative Therapies in Health and Medicine. 2002;8:74 –76.
9. Nelson KE, Sergueef N, Glonek T. Cranial manipulation induces sequential changes in blood flow velocity on demand. Amer Acad Osteopath J. 2004;14:15 -17.
10. Moskalenko YE, Kravchenko TI. Wave phenomena in movements of intracranial liquid media and the primary respiratory mechanism. Amer Acad Osteopath J.2004; 14:29 –40.
11. Gribben B, Pickering TG, Sleight P, Peto R. Effect of age and high blood pressure on baroreflex sensitivity in man. Circ Res. 1971;29:424 –431.
12. O'Brian IAD, O'Hare P, Corrall RJM. Heart rate variability in healthy subjects: effect of age and the derivation of normal ranges for tests of autonomic function. Br Heart J.1986; 55:348 –354.
13. Matsukawa T, Sugiyama Y, Watanabe T, Kobayashi F, Mano T. Baroreflex control of muscle sympathetic nerve activity is attenuated in the elderly. J Auton Nerv Syst.1998; 73:182 –185.
14. Woods JM, Woods RH. A physical finding relating to psychiatric disorders. J Am Osteopath Assoc.1961; 60:988 –993.
15. Magoun HI. Osteopathy in the Cranial Field. 2nd ed. Kirksville, Mo: The Journal Printing Company;1966 .
16. Upledger JE, Vredevoogd JD. Craniosacral Therapy. Chicago, Ill: Eastland Press;1983 .
17. Sergueef N. Le B.A.BA du Cranien. 3rd ed. Paris, France: Spek; 2000.
18. DiGiovanna E, Schiowitz S, eds. An Osteopathic Approach to Diagnosis and Treatment. 2nd ed. Philadelphia, Pa: JB Lippincott Raven Co; 1997.
19. Fernandez D, Lecine A. L'enregistrement de l'onde de Traube-Hering et de la palpation cranienne simultanee. Kinesitherapie Scientifique. 1990;292:33 –40.
20. Norton JM, Sibley G, Broder-Oldach R. Characterization of the cranial rhythmic impulse in healthy human adults. Amer Acad Osteopath J. 1992;2:9 –12,26.
21. McAdoo J, Kuchera ML. Reliability of cranial rhythmic impulse palpation . J Am Osteopath Assoc.1995; 95:491 .
22. Hanten WP, Dawson DD, Iwata M, Seiden M, Whitten FG, Zink T. Craniosacral rhythm: reliability and relationships with cardiac and respiratory rates. J Orthop Sports Phys Ther.1998; 27:213 –218.
23. Upledger JE, Karni Z. Strain plethysmography and the cranial rhythm. Proc XII Internat Conf Med Biol Eng. Jerusalem, Israel; Aug 19–24,1979; Part IV: 69.5.
24. Zanakis MF, Cebelenski RM, Dowling D, Lewandoski MA, Lauder CT, Kirchner KT, et al. The cranial kinetogram: objective quantification of cranial mobility in man . J Am Osteopath Assoc. 1994;94:761 .
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