POSTER PRESENTATION ABSTRACTS
Please note: All posters will be displayed in
Salons 10-12.
FRIDAY, 10:15-11:00 AM
MacSwain K, Kerr C.
Tactile Acuity as a psychophysical correlate in studies
of mind-body and manual therapies.
Osher Institute at Harvard Medical School osher_institute@hms.harvard.edu
While previous reviewers have suggested that modulation
of somatosensory awareness contributes to therapeutic efficacy in mind-body
and manual (massage) therapies, the underlying mechanisms remain unexplored.
This abstract reviews evidence supporting the use of tactile acuity
as a psychophysical correlate relating to somatosensory awareness in
mind-body and manual therapies. Based on this evidence, our theory is
that these therapies may, in part, derive their salubrious effects from
their ability to modulate somatosensory awareness and effect changes
in somatosensory cortical processing. As a psychophysical measure related
to broader changes in somatosensory processing, tactile acuity highly
correlates (r-squared=.83, Hodzic et al '04) with somatotopic measures
of the body map in primary somatosensory cortex (S1). Abnormalities
in tactile acuity are correlated with specific conditions that have
been successfully treated with mind-body and manual therapies. In some
studies, when such conditions subside, tactile abnormalities and cortical
maps re-normalize. Below, we describe conditions in which our theory
would suggest that tactile acuity be a relevant mechanistic correlate
of outcome.
Clinical Conditions: Balance & Posture: Tactile Acuity
diminishes with age. Poor Tactile Acuity predicts poor balance in the
elderly (Tremblay '05). In the mind-body exercise practice, Tai Chi,
practitioners are taught to focus specific somatosensory attention on
the hands and feet. Tai Chi improves balance and prevents falls in high-risk
populations of the elderly (Wayne '05). Our theory suggests that changes
in Tactile Acuity brought about through heightened somatosensory awareness
should be correlated with clinical outcomes in Tai Chi, such as decreased
fall risk and decreased fear of falling. Such a correlation would indicate
that changes in S1 underlie the therapeutic mechanism of Tai Chi for
fall risk in the elderly. Chronic Pain patients display abnormalities
of maps in S1, as well as impairments in sensory discrimination. Both
are improved through a sensory re-training therapy that includes a touch-related
component (Pleger '05).
Stress: In rat models of stress, poor tactile acuity
and disordered body maps are found (Bourgeon '04). Enriched environments
are associated with improved tactile acuity, suggesting that tactile
acuity is a correlate for both stress and stress-reduction; mind-body
and manual therapies have been found to be effective in reducing stress
(Jacobs, '01).
Anxiety: Mind-body therapies have a proven efficacy
in treatment of anxiety (Nakao '01). One recent study of mindfulness
meditation for anxiety found that mindfulness elicited a leftward shift
in EEG at S1 (Davidson, '03). This finding suggests that mechanistic
changes in S1 underlie therapeutic efficacy.
Conclusion: Tactile acuity may be significantly more
revealing of therapeutic processes than was previously realized. Based
on our review of relevant research, we suggest that changes in tactile
acuity, as well as in S1, may be correlated with therapeutic changes
in mind-body and manual therapies.
Back