Network Spinal Analysis (NSA) is a technique through which the practitioner applies light pressure at precise points along the spine closely correlated to regions where dural attachments to the bony vertebrae and contiguous structures have been demonstrated. Although patient specific, within one to three months of care, the spine exhibits a spontaneous rocking motion which is not initiated voluntarily, but can be voluntarily ceased. Retrospective and longitudinal studies have indicated that the benefits of this type of care include enhanced flexibility and physical stability of the spine. This type of care also appears to relief adverse mechanical tensions in the spinal cord. Adverse Mechanical Tensions in the Central Nervous System is a theory developed by Alf Breig, a neurosurgeon from Stockholm, Sweden. Most importantly, this kind of care seems to provide the same kind of repetitive motion that has allowed, in the well publicized case of Christopher Reeve, some late sensory and motor recovery from spinal cord injury.
The theoretical foundation of Network Spinal Analysis is Alf Breig's theory of Adverse Mechanical Tensions in the Central Nervous System. In this theory, the attachment of the dura mater to the cervical vertebra creates pathological tensions on the cord in case of vertebral misalignment or postural problems. In Network Spinal Analysis, the dural-vertebral attachment is put to use to creates an oscillation that produces the same kind of repetitive motion that has been linked to spinal cord injury recovery in the well publicized case of Christopher Reeve. The oscillation is first localized to the vertebral area but soon propagates down the spine. Likewise, the attachment of the filum terminale to the coccyx in the sacral area also creates an oscillation that propagates up the spine. The uprunning and downrunning waves along the spine eventually yield the rocking motion of the spine typical of NSA. In addition to its potential applications to spinal cord injury recovery, in less dramatic cases it provides an intensive exercise for the back musculature, not reproducible by classical physio-therapeutical means.
During the rocking motion, a fair amount of surface electromyographic (sEMG) activity is present along the spine. The sEMG signals recorded at the cervical, thoracic, lumbar, and sacral levels show "bursts of EMG activity" appearing at random and lasting anywhere from a few seconds to a minute.
The first method relies on the Canonical Correlation Analysis of the past of the raw signal at one point S (the "source") and a time-shifted version of the future of the signal at another point T (the "target"). More specifically, from the canonical correlation coefficients, the Akaike mutual information is computed versus the time-shift and, if the mutual information shows a maximum for a time-shift t_s, it can be concluded that it takes an amount of time t_s for the wave to travel from S to T. From this analysis, it appears that the "source" is the sacral area, for indeed, the correlation analysis shows an increasing amount of time for the wave to go to the lumbar, thoracic, and finally cervical area. The fact that the sacral area appears the "source" is probably related to the attachment of the filum terminale to the coccyx. Conversely, the correlation analysis did not reveal such a consistent pattern when the cervical area is viewed as the "source." This is probably related to the fact that the attachment mechanism is by far more complicated in the cervical than it is in the sacral area.
Next, another simplified analysis based on correlation between wavelet subband signals was developed. The reason for focusing on some specific subband signals is that it appeared that some of the subband signals are noise related and hence irrelevant. That part of the signal the most relevant to the wave phenomenon is the D_8 subband signal of the Daubechies wavelet decompositon of order 3 down to 8 levels. The correlation between the subband signals turned out to be much larger than the correlation between the raw signals, hence a higher confidence in our assertion that there exists a nonvanishing correlation between the signals at various points, hence a higer confidence in the assertion of existence of a wave phenomenon.
The spatio-temporal analysis was conducted on a quadriplegic subject
who had sustained the same kind of neck injury as Christopher Reeve and
who had been under NSA care for about a year and who had recovered some
control of his fingers and toes. The purpose of this study was to confirm
the spinal cord injury recovery by spatio-temporal analysis of the sEMG
signals running along the spine. The same analysis was also done on a base-line
subject, in the same experimental setup and under the same protocol as
the quadriplegic subject. The quadriplegic subject shows a weaker correlation
involving the neck signals, as can be expected, but existence of a correlation
between such distant signals as the sacral and cervical signals, with a
99% confidence level, reveals some recovery from the spinal cord
injury.
For more information about this project, contact Stephan Bohacek at bohacek@eecis.udel.edu or Poonsuk ("Matt") Lohsoonthorn at lohsoont@hotmail.com or Vikram Mahajan at vikramma@usc.edu.