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A Guide to Cleaner Skin Temperature Recordings and More Versatile Use of Your Thermistor

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Valid peripheral temperature measurements ensure the integrity of client assessment and biofeedback training. Accurate measurements require understanding of the signal and potential influences on measurement fidelity, and developing bulletproof monitoring procedures. In addition to their use in temperature biofeedback, thermistors can assist heart rate variability biofeedback practice and monitor breathing when a respirometer is not available.
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Biofeedback ÓAssociation for Applied Psychophysiology & Biofeedback
Volume 44, Issue 3, pp. 168–176 www.aapb.org
DOI: 10.5298/1081-5937-44.3.06
TECHNOLOGY CORNERTECHNOLOGY CORNER
A Guide to Cleaner Skin Temperature Recordings and
More Versatile Use of Your Thermistor
Fredric Shaffer, PhD, BCB,
1
Didier Combatalade, DC,
2
and Erik Peper, PhD, BCB
3
1
Truman State University, Center for Applied Psychophysiology, Kirksville, MO;
2
Thought Technology Ltd., Montreal, QC, Canada;
3
San Francisco State University,
San Francisco, CA
Keywords: biofeedback, peripheral temperature, tracking test
Valid peripheral temperature measurements ensure the
integrity of client assessment and biofeedback training.
Accurate measurements require understanding of the
signal and potential influences on measurement fidelity,
and developing bulletproof monitoring procedures. In
addition to their use in temperature biofeedback, thermis-
tors can assist heart rate variability biofeedback practice
and monitor breathing when a respirometer is not
available.
‘‘Cold hands, warm heart’’ or ‘‘ She is a warm person’’ are
phrases that reflect beliefs about the interconnection
between emotions, body, mind, and spirit. Temperature
biofeedback focuses on the literal measurements of body
temperature. Most biofeedback techniques take temperature
readings from the skin. More specifically, peripheral skin
temperature measurements reflect the blood flow through
the vessels under the skin. Temperature biofeedback
training can be used to help a person regulate body
temperature.
Temperature training was originally initiated in the late
1960s by Elmer Green and associates at the Menninger
Foundation and was partially derived from yoga and
autogenic training (AT) techniques (Green & Green,
1977). Autogenic training techniques related to tempera-
ture training use phrases such as ‘‘My arms are warm and
heavy’’ to induce a feeling of peripheral warmth and
heaviness (Luthe & Schultz, 1969). In addition, autogenic
training encourages use of a passive and nonjudgmental
attitude. A major goal of autogenic temperature training is
to develop an autogenic state that is the opposite of the state
triggered by the alarm reaction. Dr. Green and his
colleagues adapted these autogenic phrases and combined
them with temperature monitoring. Much of their training
included encouraging patients to adopt a passive, nonjudg-
mental attitude.
Edward Taub (1978), another early researcher in
peripheral temperature control, explored some of the
factors that affect temperature biofeedback recording and
training. Dr. Taub observed the importance of the
interpersonal dynamics associated with temperature self-
regulation. He observed the person effect. For example, an
experimenter with ‘‘an impersonal attitude toward the
experimental participants was able to train only 2 of 22
individuals to control their skin temperature while another
experimenter, using exactly the same technique, was more
informal and friendly, and trained 19 of 21 subjects’’ (Taub
& School, 1978, p. 617). This example illustrates the effects
of social interaction on autonomic learning. Conditions that
elicit striving, fear, anxiety, and performance anxiety
appear to inhibit initial learning of hand warming, whereas
conditions that elicit safety, support, caring, and acceptance
of others facilitate peripheral hand warming (Peper, Tylova,
Gibney, Harvey, & Combatalade, 2008).
Clinicians monitor skin temperature using a thermistor,
which is a sensor that converts temperature measured from
the skin surface into an electrical resistance value. Three
important properties of a temperature probe are response
time, accuracy, and resolution.
Factors That Can Affect Peripheral
Temperature
Four major factors affect the peripheral blood flow that
underlies skin temperature (Taub & School, 1978). First,
core temperature regulation impacts skin temperature. If a
subject’s core body temperature decreases while sitting in a
cool room, the biological response is peripheral vasocon-
striction (blood vessel narrowing) to reduce heat loss.
Vasoconstriction cools the skin (Peper et al., 2008).
Conversely, sitting in a warm room can trigger vasodilation
(blood vessel widening) to remove excess heat. Vasodila-
tion, which is largely mediated by beta-adrenergic agents,
warms the skin (Freedman, 1991; see Figure 1).
Second, pharmaceutical agents can cause peripheral
vasoconstriction (e.g., caffeine and nicotine) or vasodilation
(e.g., alcohol).
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Third, sympathetic arousal, especially fear, causes
peripheral vasoconstriction, while anger will sometimes
cause peripheral vasodilation.
Finally, respiration can produce peripheral vasoconstric-
tion or vasodilation. Hyperventilation, which results in low
end-tidal CO
2
values (the percentage of CO
2
in exhaled air),
usually causes vasoconstriction. In contrast, breathing more
slowly than six breaths per minute, which can increase end-
tidal CO
2
, often produces vasodilation (Lynch & Schuri,
1978).
R. Gevirtz (personal communication, April 7, 2016) has
recommended adding inexpensive temperature monitoring
to heart rate variability biofeedback (HRVB) practice, since
many clients will exhibit hand warming when they breathe
at their resonance frequency (the rate that most effectively
stimulates their cardiovascular system). Conversely, Peper
(personal observations, 2016) points out that a decrease in
peripheral temperature usually indicates that the person is
‘‘trying too hard’’ to breathe correctly at the resonance
frequency and may be unknowingly overbreathing.
Thermal Process of Temperature Recording
with a Thermistor
A thermistor does not directly measure skin temperature.
It measures its own temperature, which is the result of
heating or cooling through thermal conduction/radiation to
the skin and the air. For example, if the actual skin
temperature is 928F and the room temperature is 748F, the
side of the thermistor touching the skin is warmed to 928F.
The side covered by tape and exposed to the room radiates
heat to the room, thereby slightly cooling the thermistor.
Thus, the recorded finger temperature is most likely 90.58F
and depends upon the degree of thermal insulation by the
band or tape.
This phenomenon can easily be checked by recording the
temperature of the index finger and thumb and then
touching the index finger and thumb together. When they
touch, the temperature will go up 18to 28F. The resultant
temperature will be the actual temperature of the finger and
thumb as confirmed by thermographic measurements.
Response Time
When providing skin temperature biofeedback, there is
normally a noticeable delay between a physiological change
and the time the temperature signal starts responding. The
hardware contribution to this delay is called the time
constant of the thermistor. It takes the bit of time to warm
up or cool down. A time constant is a period required for
the thermistor to reach 63.2% of a final value. You’re
sitting in a 748F room. How long should a thermistor with a
timeconstantof1secondtaketoregisterahand
temperature of 928F? The thermistor will reach 99.8% of
your hand temperature in 5 time constants, or 5 seconds.
Peper et al. (2008) described a procedure for measuring
response time of the thermistor.
The skin’s contribution to this delay is more important.
It takes time for the skin to warm up or cool down when
there is dilation or constriction of cutaneous blood vessels.
When comparing skin temperature and blood volume pulse
amplitude, there is a greater delay in skin temperature than
blood volume pulse responses to a stressor, approximately
30 seconds versus approximately 0.5–3 seconds (see Figure
2).
Temperature can also be measured from a distance using
an infrared sensor. Since it is a camera, a passive infrared
(pIR) sensor responds more quickly to changes in infrared
radiation from blood circulation than a thermistor (see
Figure 3). Passive infrared is generally designed to monitor
temperature from a wider area than a thermistor. The
further a sensor is from its target, the larger is the surface
area it records. Since a pIR sensor must be positioned a
short distance from the skin, it is a poor choice for
temperature training. Also, the pIR signal appears noisier
because the infrared camera detects very small changes in
the heat radiating from the surface of the skin. The signal
must be slightly smoothed (averaged) to reveal longer
trends in temperature change.
Figure 1. Vasoconstriction and vasodilation.
Shaffer et al.
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Biofeedback |Fall 2016
Since a temperature probe only contributes a few
seconds to this lag, response time is not critical. The major
advantage of the pIR sensor is that the sensor is not in
contact with the tissue; thus, it can be used to monitor
temperature of open wounds to facilitate blood flow (Olesen
& Peper, 1985).
Accuracy
An absolute accuracy of 18F should be adequate for
temperature biofeedback training (Peek, 2016). Generally,
the immediate detection and display of relative physiolog-
ical changes is more important to biofeedback training than
absolute accuracy. Use a laboratory-grade alcohol or
Figure 2. Comparison of photoplethysmograph and thermistor signals.
Figure 3. Comparison of thermistor and passive infrared (pIR) signals.
Guide to Cleaner Skin Temperature Recordings
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mercury thermometer as your reference to test feedback
thermometer accuracy. Place the thermistor next to the
mercury thermometer and compare room temperature
values. Peper recommends that professionals know their
typical measurements so that they can use themselves as
‘‘test equipment’’ when values appear questionable (Peper
et al., 2008, pp. 118–120).
Absolute accuracy is important when you want to teach
people to warm to specific criteria such as their hands to
958F and feet to 938F as suggested for the treatment of
hypertension (Fahrion, Norris, Green, Green, & Snarr,
1986). In these cases, you will need the accuracy of a
clinical-grade thermistor. In addition, you have to allow for
the cooling effect of the room. A recorded value of 958F
may in fact be 96.58F if the room has chilled the thermistor
by 1.58F.
Resolution
The resolution of a temperature biofeedback instrument is
the smallest increment of change that it can measure and
display. If a sensor’s resolution is too low, it will be unable
to detect small changes in temperature. If it is too high, it
will detect minute temperature changes and noise, which
will increase signal variability and cause erratic feedback,
possibly interfering with the learning process. A resolution
of 0.18F is a good compromise value because it provides
rapid feedback that is relatively insensitive to artifacts (false
signals) due to sources like circuitry heating, drafts, and
movement.
Ceiling Effect
Skin temperature is limited by core body temperature. As a
result, success in hand warming does not depend on
increasing the temperature by a certain number of degrees,
but rather on the number of degrees of change relative to a
ceiling of approximately 978F. This phenomenon is called a
ceiling effect. If a person’s hand temperature starts at 678F,
it can be increased by 308F before it reaches a temperature
of 978F—near the core body temperature. On the other
hand, if a person’s hand temperature starts at 958F, the total
temperature can only increase by 28F. In both examples,
hand temperature increases of 308For28F represent very
successful peripheral warming (Peper et al., 2008).
Thermistor Placement
Temperature biofeedback is about monitoring the changes
in skin temperature that are caused by autonomic and
endocrine activity. These changes are easier to detect in the
peripheral circulation, so hands and feet are ideal locations.
A thermistor should be attached using Velcrotor Cobane
tape to a site on the hand or foot that is well-supplied with
blood vessels. When fastening the sensor, be sure that the
tip (bead) of the sensor is pressed against the fleshy part of
the finger or toe, but be careful not to wrap the Velcrotor
Cobanetape so tightly that circulation is reduced.
Meehan et al. (manuscript in preparation) found that the
back of the index and middle fingers of the left and right
hands were at least 18F warmer than the palmar aspect of
these digits in a sample of 49 undergraduates (20 men and
29 women), ages 18–26.
Besides digits, the web dorsum, located on the back of
the hand between the thumb and index finger, is also a good
place to attach the sensor. Adhesive porous tape would be
used in this case.
Despite competing claims for the superiority of specific
hand sites or hands, there is no peer-reviewed evidence that
a single site is most responsive to stressors or relaxation
exercises across a majority of patients (Peek, 2016). Further,
during an individual patient’s training session, an initially
responsive site may plateau (cease to warm). Since
temperature biofeedback to produce hand warming can be
overly specific (warming could be confined to just the left
index finger), several sites should be monitored during a
session to determine the generalization vasodilation. Since
thermistors are expensive, two options are to move the
same sensor to different sites or to scan the hands using an
inexpensive infrared thermometer (see Figure 4).
We usually recommend placing a thermistor on the end
of the index finger or thumb because of their greater
temperature range (see Figure 5). The lowest temperature is
Figure 4. Infrared thermometer monitoring a vasoconstricted thumb.
Shaffer et al.
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observed at the tips of the fingers if room temperature is
lower than core temperature. In addition, the ends of the
fingers have higher densities of proprioceptive receptors
than the web of the hand. This allows clients to more easily
feel the sensations of warmth. Usually when finger
temperature is about 908F, subjects start to feel the
throbbing of their pulse at the fingertip.
Monitoring Conditions
Theroomshouldbearound748F when measuring
temperature. Rooms below 688F may produce a downward
temperature drift as peripheral blood vessels constrict to
reduce body heat loss and maintain core temperature.
Remove your patient from drafts and cool surfaces and
provide seating with sufficient neck and knee support.
Plants may be used to diffuse drafts. Conversely, warm
rooms may elevate temperatures. A cadaver’s hand
temperature will be 908Fina908F room. Experienced
professionals record room temperature along with client
baseline values.
Usually, it is easier for subjects to warm their hands
when the palm faces downward and feels the warmth of the
thigh than when it faces upward and feels the coolness of
the air.
Quality Control
The most important rule is to record under similar
conditions since only then can you compare data. While it
is valid to compare temperature values within a single
session, across-session comparisons are less valid because
many conditions may have changed between sessions. For
example, the client’s initial temperature, office temperature,
and sensor placement may have changed. You can reduce
these sources of variability by standardizing your methods.
While trend graphs (plotting values across multiple
sessions) may often show considerable variability between
adjacent sessions, they should help you demonstrate a
learning curve. If your client is learning to self-regulate,
you should see a warming trend in the session-to-session
values. This, along with improvement in your client’s
symptoms or performance, should help you document
temperature biofeedback training effectiveness.
Professionals should take precautions against five
temperature recording issues: constriction, blanketing,
warming by the thigh, movement, and position.
First, constriction occurs when tape is tightly wrapped
around the circumference of the digit, which could reduce
blood flow and produce lower readings. Instead, apply tape
over the bead and cable, following the cable.
Second, blanketing results when too much material is
used to wrap around the finger and heat is trapped inside.
Zerr et al. (2015) found that this raised finger temperature
by nearly 18F. When using Velcrot, be sure to wrap around
the sensor so you can see the bead close to the edge of the
band. When using tape, don’t cover the bead fully or use
porous tape that will allow air to flow. If the tape thermally
insulates the probe and finger, it will reduce the observed
vasoconstriction of the fingers because the fingers are
staying warm because of the tape. This is similar to wearing
gloves in colder weather. For consistency, use a single layer
of tape.
Third, warming by the thigh can directly and indirectly
heat a thermistor, so that the recorded temperature is
somewhere between finger and thigh temperature (see
Figure 6). When the thermistor attached to a cold finger
touches the thigh, it may increase the temperature as much
as 10 or more degrees. The thermistor is exposed to heat
radiating from the thigh, this may increase temperature by
0.5 to 1.08F (Meehan et al., in press). A thick towel, which
should be replaced between clients to mitigate infection
transmission, can avoid this problem.
Although you can instruct clients to rest their hands on
the thigh with the palms up, this often will cause cooling of
the fingers as the person becomes aware of the cool air and
the slight sweating of the exposed palms cools the fingers.
Also, be aware that the fingers can curl in such a way that
the thumb, or an adjacent finger, will touch the sensor and
warm it up. Booiman (personal communication, March 26,
2016) recommends recording from the inner aspect of the
thumb, since there is gap between the thumb and index
finger. A compromise is to secure the thermistor on the side
of the index finger.
Figure 5. Thermistor placement at the fingertip.
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Fourth, movement can decouple the thermistor from the
skin by tugging on the sensor cable. This can lift the
sensing bead from the skin (see Figure 7). You can
minimize this problem by taping the thermistor cable
down to your patient’s shirt or blouse (and possibly also to
a reclining chair) with sufficient slack.
Finally, a positional effect results when the hand is
placed above the heart and gravity lowers temperature by
reducing the amount of blood perfusion in the skin. Figure
8 shows the effect of moving the client’s hand above and
below heart level. It also shows how movement artifacts
occur each time the subject moves. When recording,
standardize hand elevation.
While early biofeedback texts warned clinicians against
the stem effect, cooling due to not securing the first 3 inches
of a thermistor, Zerr et al. (2015) found no evidence of this
artifact when recording from undergraduates. The disap-
pearance of this phenomenon may be due to improved
thermistor design.
The Importance of Temperature Scale
One last thing to be careful about, when providing skin
temperature biofeedback, is the scale setting on the screen’s
feedback graph. Temperature is a very slow signal that
rarely exhibits much variability. Setting the scale too
widely or too narrowly can give inconsistent feedback to the
client and cause confusion. A scale that is too wide will
flatten out the signal and small but meaningful changes will
never be shown. A scale that is too narrow will make
insignificant changes seem like large ones and confuse your
client.
Observe the temperature changes during the baseline
period and set the scale’s maximum value slightly above the
maximum and its minimum value to below the lowest
baseline reading. For temperature training and to reveal
temperature changes, we often set the range at plus or
minus 28F of the baseline value.
Tracking Test
Atracking test, previously called a behavior test, checks the
relative integrity of the entire signal chain from the
thermistor to the encoder, the correct software selection
of input channels, and display settings. You can determine
whether a temperature display mirrors the thermistor’s
temperature changes by performing a tracking test, during
which you gently blow on the thermistor bead to warm it.
Be sure to bring it very close to the mouth; otherwise,
you may be moving the cooler room temperature over the
thermistor. Temperature should increase while you blow
and then decrease when you stop.
Figure 6. Thermistor warming due to contact with the thigh.
Figure 7. Thermistor decoupling due to movement.
Shaffer et al.
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Biofeedback |Fall 2016
If the tracking test fails, review each element in the
chain. Check that the sensor is properly inserted into the
correct encoder channel, double-check your sensor place-
ment, and make sure that you’re not actually replaying
previously recorded data. If you have more than one probe,
try substituting probes to see if the first one might be
defective. Finally, if all else fails, contact your vendor’s
technical support department.
To check the relative accuracy of the thermistor, place it
underneath your armpit, wait a minute, and the temper-
ature should approach core temperature.
Baselines
Temperature baselines are resting measurements obtained
while a client is resting without feedback. For publishable
research, a baseline period should allow temperature to
stabilize within 0.58F for at least 5 minutes. Stabilization
happens at two levels. First, the sensor itself needs sufficient
time to reach the client’s skin temperature. Then, the client
has to adapt to your room’s ambient temperature (see
Figure 9).
Baseline length will vary with each subject between 15
and45minutesina748F room. Cold outdoor temper-
ature can delay stabilization by 20 minutes (Khazan,
2013).
Due to practical concerns, clinical baselines are often as
brief as 3 minutes during training sessions. Be cautious that
if a patient hasn’t stabilized before the training session
starts, warming during the session may reflect adjustment
to the room environment instead of self-regulation. As
soon as clients sit in the training chair, let them hold the
thermistor in their hand, even unconnected, to start
warming it right away. Then, affix it to the clients’ finger
when you have finished your setup procedure.
A baseline measurement is usually only meaningful in
the first few sessions. After people have learned peripheral
warming, sitting in the baseline condition will usually
evoke hand warming. The hand will progressively warm as
they relax.
Normal Values and the Circadian Rhythm
The average core body temperature is usually around
98.68F and varies by 1.38F during the day due to the
endogenous circadian rhythm (lowest in early morning and
higher in late afternoon). The time of day can significantly
affect skin temperature. Higher skin temperatures are more
Figure 8. Effect of hand position with respect to the heart on skin temperature.
Figure 9. Temperature stabilization.
Guide to Cleaner Skin Temperature Recordings
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Fall 2016 |Biofeedback
easily attained in the late afternoon and early evening. This
is relevant for clinicians because they often see clients early
in the morning before they go to work (normal core
temperature 97.78F) or late in the afternoon/early evening
when they come from work (normal core temperature
99.08F) (Duffy, Dijk, Klerman, & Czeisler, 1998). Again,
when recording, the maximum temperature can be slightly
higher in the early evening than early morning. When
analyzing data, be sure to compare absolute data from
similar times of the day.
Peripheral temperature detected from the hands and feet
is much lower. Normal finger temperatures range widely.
Temperature values for men fall along a normal curve;
those for women are bimodal. Finger temperatures exceed
888F and toe temperatures reach about 858F. Men have
average hand temperatures of 908F compared with 87.28F
for women; a 2.88F difference (Conant, 2016).
Depending upon the degree of heat loss from the fingers
to a cooler room, clinicians can up-train finger temperature
to 958F and toe temperature to 938Fina748F room
(Khazan, 2013, pp. 45, 159). If the room is warmer than
808F, you can up-train finger temperature to nearly 96.58F
and foot temperature to 958F.
Temperature Variability
Shusterman (1995) reported that the skin temperature
signal contains oscillations in the 0.015–0.04 Hz range for
both healthy subjects and those diagnosed with coronary
artery disease. These oscillations are termed temperature
variability (TV). The power spectra for TV and heart rate
variability (HRV), which overlap, showed parallel changes
in response to stressors. TV was more sensitive to stressors
than mean temperature.
Thermistor Monitoring of Respiration
R. Gevirtz (personal communication, March 11, 2016)
recommended placement of a temperature probe below the
nostril to monitoring breathing when you don’t have a
respirometer (flexible respiration sensor placed around the
abdomen or chest). This technique was discussed in the
1970s and works when the nostril is unobstructed and the
probe is located at the opening of the nostrils.
As shown by Figure 10, there are three caveats to this
approach. First, the temperature-based respiration signal
is the reverse of a respirometer waveform (inhalation ¼
colder ¼down; exhalation ¼warmer ¼up). Second, the
two signals will be slightly out of phase since a
thermistor tracks temperature changes more sluggishly.
Finally, as a client breathes more rapidly or more
shallowly,thethermistorislessabletorespondto
briefer or less marked temperature changes, and the
signal flattens out.
Summary
Skilled temperature monitoring requires familiarity with
clean signals, normal values, and understanding of the
factors that can affect signals. As with all biofeedback
modalities, visual inspection of the raw signal is essential
to ensuring measurement fidelity. While clinicians
primarily use thermistors to monitor peripheral temper-
Figure 10. Respirometer and nasal thermistor waveforms.
Shaffer et al.
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ature during thermal biofeedback, they can provide
valuable information during HRVB practice and detect
respiration when a respirometer is not available.
References
Conant, E. (2016). Degrees of separation. Retrieved July 23, 2016,
from http://ngm.nationalgeographic.com/2014/05/next/
thermal-imaging
Duffy, J. F., Dijk, D. J., Klerman, E. B., & Czeisler, C. A. (1998).
Later endogenous circadian temperature nadir relative to an
earlier wake time in older people. American Journal of
Physiology, 275(5, Pt 2), R1478–R1487.
Fahrion, S., Norris, P., Green, A., Green, E., & Snarr, C. (1986).
Biobehavioral treatment of essential hypertension: A group
outcome study. Biofeedback and Self-Regulation, 11(4), 257–
277.
Freedman, R. R. (1991). Physiological mechanism of temperature
biofeedback. Biofeedback and Self-Regulation, 16(2), 95–115.
Green, E. E., & Green, A. M. (1977). Beyond biofeedback. New
York: Delacorte.
Khazan, I. (2013). The clinical handbook of biofeedback: A step-
by-step guide for training and practice with mindfulness.
Chichester, West Sussex, UK: Wiley.
Luthe, W., & Schultz, J. H. (1969). Autogenic therapy: Vol. 1.
Autogenic methods. New York: Grune & Stratton.
Lynch, W. C., & Schuri, U. (1978). Acquired control of peripheral
vascular responses. In G. E. Schwartz, & D. Shapiro (Eds.),
Consciousness and self-regulation. New York: Springer.
Meehan, Z., Bartochowski, Z., West, A., & Shaffer, F. (Manuscript
in preparation). Differences in dorsal and ventral temperatures
of the index and middle fingers.
Meehan, Z., Bartochowski, Z., West, A., Musenfechter, N., Owen,
D., Crawford, A., . . . Shaffer, F. (in press). Quantifying thigh
artifact during hand temperature measurement [Abstract].
Applied Pscyophysiology & Biofeedback.
Olesen, E., & Peper, E. (1985). Temperature biofeedback: Some
advantages of infrared thermometer biofeedback [Abstract].
Biofeedback and Self-Regulation,10(1), 110.
Peek, C. J. (2016). A primer of traditional biofeedback instrumen-
tation. In M. Schwartz & F. Andrasik (Eds.). Biofeedback: A
practitioner’s guide (4th ed.). New York: Guilford.
Peper, E., Tylova, H., Gibney, K. H., Harvey, R., & Combatalade,
D. (2008). Biofeedback mastery: An experiential teaching and
self-training manual. Wheat Ridge, CO: AAPB.
Shusterman, V., & Barnea, O. (1995). Spectral characteristics of
skin temperature indicate peripheral stress-response. Biofeed-
back & Self-Regulation, 20(4), 357–367. doi: 10.1007/
BF01543790
Taub, E., & School, P. J. (1978). Some methodological consider-
ations in thermal biofeedback training. Behavior Research
Methods & Instrumentation, 10(5), 617–622.
Zerr, C., Kane, A., Vodopest, T., Allen, J., Fabbri, M., Williams, C.,
Shaffer, F. (2015). Are blanketing and stem artifacts real?
[Abstract]. Applied Psychophysiology and Biofeedback, 40(2),
134–135. doi:10.1007/s10484-015-9282-0
Fredric Shaffer Didier Combatalade Erik Peper
Correspondence: Fredric Shaffer, PhD, BCB, Truman State
University, Center for Applied Psychophysiology, 100 E. Normal,
Kirksville, MO 63501, email: fredricshaffer@gmail.com.
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... The average increase of finger temperature for five sessions is 0.214 degrees of Celsius per minute. Thus, conducted biofeedback sessions were successful since each resulted in a higher ending temperature, leading to increased relaxation [20]. Skin conductance for biofeedback sessions is presented in Fig. 6. ...
... Various clinical and experimental studies have documented the temperature in the hands to establish the vulnerability of suffering from a chronic inflammatory disease, as well as the skin's thermal recovery capacity (Sousa et al., 2017). Shaffer, Combatalade, and Peper (2016) describe the autonomic mechanisms, conditions, and affective states, such as fear, stress, or performance anxiety, that participate in the peripheral thermal response in hands: a high firing rate of sympathetic activation induces vasoconstriction in the arteries, which decreases the temperature, whereas a low sympathetic firing rate induces vasodilation, which increases the temperature in this ROI. ...
Article
Human stress is a physical or emotional feeling. It can come from any situation or thought that makes one feel frustrated or nervous. Different biological manifestations take place in the presence of stress, such as tension, headache, and insomnia. Recent studies have reported that human stress can be related to facial expressions and fingertips due to temperature changes in the skin. Infrared thermography is a non-invasive technology that allows for the monitoring and analysis of human skin temperature. However, many works reported in the literature perform a manual analysis, depending on expert personnel, resulting in considerable human and economic efforts. In addition, the analyses reported to date with thermography are only based on the study of body parts. To reduce the limitations of these methodologies, expert systems have been proposed that simulate the thought process of a human expert to solve decision problems, which may be helpful for people focused on the health and psychology area who do not have expertise in the study of stress. Therefore, this paper proposes a novel expert system based on infrared thermography and thermal analysis of facial skin and fingertips, a rule-based method, and heuristic knowledge to classify and diagnose human stress in undergraduate university students. The system had the support of experts in the study of human stress and was validated in a stress study. The novel expert system was implemented in a local database that consisted of a group of 100 participants, undergraduate university students, of which 70 were stimulated by the Trier Social Stress Test (TSST) protocol and 30 were not induced to human stress, obtaining an accuracy in the expert system stress classification of 91.0%.
... Body temperature is also regulated by autonomic response, and a reduction of blood flow in these areas is an indication of high stress level whereas passivity is related to higher temperature. Therefore the relationship between body temperature and stress is inverse: the higher is the stress, the lower is the body temperature [24]. ...
Chapter
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Biofeedback is a technique of self-regulation applied by health professionals in order to reshape a series of physiological information based in health parameters diminishing psychopathological symptoms and improving cognitive performance. The biofeedback technique is widely recognized in many countries, leaving no doubt about its effectiveness and applicability. In clinical psychology, biofeedback has been applied effectively to psychophysiological conditions such as anxiety, depression and ADHD. This chapter has the aim to elucidate the techniques applied to clinical settings, where psychophysiological conditions are more prone to be treated with biofeedback. Moreover, this chapter also evaluates the advances of the technique and possible future directions.
... A known contribution by Dr. Edward Taub to the understanding of the therapeutic relationship in biofeedback therapy is related to the therapist's warmth, known as the person effect (Shaffer, Combatalade, & Peper, 2016). Taub and School (1978) observed that an impersonal attitude expressed by a researcher during thermal biofeedback research resulted in poor achievements of the participants in which only 2 out of 22 participants learned to control their skin temperature. ...
... These changes are easier to detect in the peripheral circulation, so hands and feet are ideal locations. 312 Some of the temperature measurement may be implemented as a skin temperature measurement system. The system aims to measure the skin temperature from a sensor and send it to the PC using a USB cable to display on screen. ...
Research
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This is a qualitative research consisting of three objectives, namely: - (1) to explore the concept of happiness access according to Buddhist principles and the concept of Gross National Happiness (GNH); (2) to examine the theory of biofeedback; and (3) to propose a conceptual model of Bi-Dimensional development for happiness access by biofeedback process. The data collection and in-depth interviews were carried out with 8 key-informants from 6 countries. They are monks and Buddhist scholarly representatives with the IOC examined by 3 experts. The findings show Buddhism suggests the access of superior happiness by dealing with the dukkha-sukha dichotomy of dualism; while the practice of GNH constructed by the four pillars with the middle path, contentment and social engagement. The Biofeedback skillfully employed the instruments, EMG, EEG, etc. into treatments. When they are integrated with the Buddhist meditation, a practitioner can entrain the assessment of happiness in a tangible way. As for the Model created suggests the Bi-Dimensional development for happiness access. First, MENTAL Dimension to access the fivefold happiness in concentration, namely: - Gladdening (pāmojja), Happiness (pīti), Tranquility (passaddhi), Bliss (sukha), and Concentration (samādhi). The biofeedback means can be utilized for happiness measurement from the mind-body phenomena in the practice. Second, WISDOM Dimension for perpetual happiness access is Nibbāna, the supreme happiness.
Poster
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The Neurovisceral Integration Model proposes that the reciprocity between the autonomic and central nervous systems facilitates an individual’s ability to respond appropriately to environmental demands by proper vagal withdrawal and recovery. Neuroimaging studies have shown the prefrontal cortex to be significantly associated with Heart Rate Variability (HRV) via the vagus nerve. Correspondingly, HRV has been shown to be associated with performance on tasks involving executive functions, such as attention, working memory and inhibition. The current study examines the relationship between cognitive performance and vagal tone, withdrawal, and recovery. Vagal tone, measured by the natural log of High Frequency (LnHF), was collected at rest for 10 min, during a cognitive stressor (Serial 7’s, while being pressed for time by the examiner), followed by a 5 min of recovery period. Vagal withdrawal was measured by the difference between LnHF at rest and during stress. Vagal recovery was measured as the difference between LnHF during recovery period and during stress. The Paced Auditory Serial Addition Test (PASAT) was used to assess auditory information processing and working memory in 15 healthy participants. A series of single digits were presented via an audio recording at the rate of one every 3 s (condition 1) and one every 2 s (condition 2) while the examinee was asked to add each number to the preceding number heard on the recording. Preliminary data (n = 15) show that PASAT performance during the 2 s condition, but not the 3 s condition demonstrated statistically significant association with vagal withdrawal and recovery (r = .739, p = .003 and r = .540, p = .046, respectively). Neither condition was associated with vagal tone at rest. Although cognitive performance was not related to resting vagal tone, it was significantly associated with vagal withdrawal and recovery. This indicates that an individual’s ability to appropriately respond to cognitive demands may be better assessed by dynamic vagal reactivity to stress. These findings support and extend the Neurovisceral Integration Model by specifying the vagal characteristics most related to cognitive performance. Further research should investigate the effects of biofeedback training on improving cognitive performance.
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The present chapter addresses the question of whether or not experience can lead to a modification of peripheral vascular function. Under normal circumstances, the vascular system of most mammals is regulated by automatic mechanisms. At issue here is whether individuals can learn to modify this automatic regulation.
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Discusses the effects of biofeedback on various conditions such as high blood pressure, epilepsy, and anxiety tension states. The broader implications of self-regulation for areas including creativity, meditation, consciousness states, and psychotherapy are then examined. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Research on the physiological mechanisms of finger temperature biofeedback with normal subjects and Raynaud's disease patients is reviewed. Studies conducted in the author's laboratory have shown that feedback-induced vasodilation is mediated through a non-neural, -adrenergic mechanism rather than through reductions in sympathetic nervous system activation. In contrast, feedback-induced vasoconstriction is mediated through the traditional, sympathetic nervous pathway. When used with primary Raynaud's disease patients, feedback-induced vasodilation has achieved reductions in reported symptom frequency ranging from 66% to 92% in controlled investigations. Future research directions are discussed.
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High-resolution measurement of skin temperature in 11 normal subjects revealed low-amplitude temperature oscillations (40 10–3C). The temperature signal measured on two hands during baseline, stress, and recovery periods, was filtered to separate the low-amplitude oscillations from the temperature signal. Spectral analysis of the filtered signal showed that most of the energy of the signal is in a range of 0.01 to 0.03 Hz. Frequency shifts and amplitude changes of the largest component were observed in response to mental stress. In subjects with high baseline values of either of these two variables, a decrease was observed in response to stress. An opposite response was observed in subjects with significantly lower baseline levels. Stress-related changes in peak frequency ranged from –25% to +18.2%; changes in peak amplitude ranged from –74.6% to +280%. Changes in the mean temperature were limited to 2.4%. Thus, the oscillatory component showed higher sensitivity to psychological stress than mean temperature. The spectrum of this component was compared to the spectrum of the blood pressure waves measured noninvasively. Both exhibited similar dynamics of energy, peak amplitude, and peak frequency in response to psychological stress. This similarity suggests that the oscillatory temperature component reflects stress-related changes of peripheral vasomotor activity.
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This article attempts to provide guidelines for acceptable practice in thermal biofeedback training. Criteria are set forth in three major areas: the nature of the interaction between the experimenter/therapist and subject/patient, training procedures, and the physical characteristics of the temperature sensing and feedback system.
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Research on the physiological mechanisms of finger temperature biofeedback with normal subjects and Raynaud's disease patients is reviewed. Studies conducted in the author's laboratory have shown that feedback-induced vasodilation is mediated through a non-neural, beta-adrenergic mechanism rather than through reductions in sympathetic nervous system activation. In contrast, feedback-induced vasoconstriction is mediated through the traditional, sympathetic nervous pathway. When used with primary Raynaud's disease patients, feedback-induced vasodilation has achieved reductions in reported symptom frequency ranging from 66% to 92% in controlled investigations. Future research directions are discussed.
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In a group outcome and follow-up study of 77 patients with essential hypertension, significant reductions were seen in systolic and diastolic blood pressure (BP) and in hypotensive medication requirement. A multimodality biobehavioral treatment was used which included biofeedback-assisted training techniques aimed at teaching self-regulation of vasodilation in the hands and feet. Of the 54 medicated patients, 58% were able to eliminate hypotensive medication while at the same time reducing BP an average of 15/10 mm Hg. An additional 19 (35%) of the medicated patients were able to cut their medications approximately in half while reducing BP by 18/10 mm Hg. The remaining 4 (7%) medicated patients showed no improvement in either BP or medication requirement. Similar reductions in BP were seen in initially unmedicated patients. Seventy percent of the 23 unmedicated patients achieved average pressures below 140/90 mm Hg, with an additional 22% of these patients making clinically significant reductions in pressure without becoming normotensive, and with 8% unsuccessful at lowering pressures to a clinically significant extent. Follow-up data available on 61 patients over an average of 33 months indicated little regression in these results with 51% of the total patient sample remaining well-controlled off medication, an additional 41% partially controlled, and 8% unsuccessful in lowering either medications and/or blood pressures to a clinically significant extent.