Quantitative assessment of foot sensitivity [Elektronische Ressource] : the effects of foot sole skin temperature, blood flow at the foot area and footwear / Günther Schlee
95 Pages
English
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Quantitative assessment of foot sensitivity [Elektronische Ressource] : the effects of foot sole skin temperature, blood flow at the foot area and footwear / Günther Schlee

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95 Pages
English

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Günther Schlee Quantitative assessment of foot sensitivity: The effects of foot sole skin temperature, blood flow at the foot area and footwear D o c t o r a l T h e s i s Submitted to Faculty of Behavioral and Social Sciences of the Chemnitz University of Technology, to fulfill the requirements for the degree of doctor rerum naturalium (Dr. rer. nat.) April 2010 Günther Schlee Der Einfluss der Temperatur der Fußsohle, des Blutflusses im Fußbereich und des Schuhwerks auf die plantare Fußsensibilität D i s s e r t a t i o n zur Erlangung des akademischen Grades doctor rerum naturalium (Dr. rer. nat.) vorgelegt der Fakultät für Human und Sozial Wissenschaften der Technischen Universität Chemnitz April 2010 Datum des Promotionskolloquiums: 30/08/2010 Vorsitzender des Promotionskolloquiums: Prof. Dr. Udo Rudolph Erstgutachter: Prof. Dr. Thomas L. Milani Zweitgutachter: Prof. Dr. Wilfried Alt “Following our instincts, not a trend” James Hetfield I could not leave the opportunity to acknowledge a few people, who were fundamental during the process of completing this work. First and foremost, I would like to thank Thomas for providing me with the opportunity to come to Germany, for his advices and well as his patience during all these years, both in professional and personal manners.

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Published 01 January 2010
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Exrait



Günther Schlee


Quantitative assessment of foot sensitivity: The
effects of foot sole skin temperature, blood flow at
the foot area and footwear


D o c t o r a l T h e s i s

Submitted to Faculty of Behavioral and Social Sciences of the Chemnitz
University of Technology,
to fulfill the requirements
for the degree of
doctor rerum naturalium (Dr. rer. nat.)





April 2010

Günther Schlee


Der Einfluss der Temperatur der Fußsohle, des
Blutflusses im Fußbereich und des Schuhwerks
auf die plantare Fußsensibilität


D i s s e r t a t i o n

zur Erlangung des akademischen Grades
doctor rerum naturalium (Dr. rer. nat.)

vorgelegt der Fakultät für Human und Sozial Wissenschaften der
Technischen Universität Chemnitz





April 2010

















Datum des Promotionskolloquiums: 30/08/2010
Vorsitzender des Promotionskolloquiums: Prof. Dr. Udo Rudolph


Erstgutachter: Prof. Dr. Thomas L. Milani
Zweitgutachter: Prof. Dr. Wilfried Alt





“Following our instincts, not a trend”
James Hetfield

I could not leave the opportunity to acknowledge a few people, who were fundamental during
the process of completing this work.

First and foremost, I would like to thank Thomas for providing me with the opportunity to
come to Germany, for his advices and well as his patience during all these years, both in
professional and personal manners. It’s been definitely an experience for live, thank you very
much!

I would also like to thank all my friends and colleagues, who have helped me to quickly
become “a German guy”. I’m not going to name you all, otherwise I will not have enough
space to thank other people, but you know who you are! However, I would like to especially
acknowledge Thorsten, for all his support and help to push this work further.

A very special, loving thank you goes to my family and all my Brazilian friends, who have
visited me in Germany over all this years and brought a taste of home every now and then. I
would like to especially thank, of course, my mother, who has made everything it was
humanly possible to provide us with the wonderful opportunities we’ve had.

Life in Germany has been really good to me. So good, that I even met my future wife!
Kathrin, thank you. Thank you for your love and comprehension, for your words and
determination. They all inspire me to try and get better. Thank you a lot for your patience, I
know dealing with me is not easy sometimes.

O meu útimo obrigado, e nao por isso o menos importante, vai para Deus e o meu Hepteto
Sagrado. Vocês sabem o por quê.



List of contents


List of contents

List of figures ........................................................................................................................ ii
List of tables ........................................................................................................................ iii
List of Abbreviations ............................................................................................................ iv
Abstract ................................................................................................................................1
Zusammenfassung...............................................................................................................3
Structure of the document ....................................................................................................5
Session 1.................................................................................................................................6
1.1 Rationale ........................................................................................................................6
1.2 Literature ......................................................................................................................10
1.2.1 Perception of mechanical stimuli...........................................................................10
1.2.2 Mechanoreceptors in the foot skin.........................................................................11
1.2.2.1 Adaptation properties of mechanoreceptors...................................................13
1.2.2.2 Distribution of mechanoreceptors in the foot sole ..........................................14
1.2.2.3 Functional structure of Meissner corpuscles ..................................................17
1.2.2.4 Functional structure of Vater-Pacini corpuscles .............................................18
1.2.2.5 Transmission of afferent stimuli......................................................................20
1.2.3 Clinical application of sensory measurements ......................................................21
1.2.3.1 Foot vibration sensitivity and skin temperature ..............................................23
1.2.3.2 Footnsitivity and blood flow .........................................................25
1.2.3.3 Foot vibration sensitivity and footwear ...........................................................26
1.2.3.4 Footnsitivity and gender ..............................................................28
1.2.3.5 Foot vibration sensitivity and plantar foot anatomical location .......................29
1.2.4 Sensorimotor Integration .......................................................................................29
1.3 Definition of the studies/hypotheses.............................................................................32
Session 2...............................................................................................................................33
2.1 Study 1: Foot sole skin temperature affects plantar foot sensitivity..............................33
2.2 Study 2: Short-time lower leg ischemia reduces plantar foot sensitivity.......................45
2.3 Study 3: Effects of footwear on plantar foot sensitivity: a study with Formula 1 shoes 57
Session 3.........70
3.1 Discussion ....................................................................................................................70
3.1.1 Summary of the hypothesis/results of the single studies.......................................70
3.1.2 Combined discussion of the results.......................................................................71
3.1.2 Conclusion and future perspectives ......................................................................76
3.2 References (not listed in the articles) ...........................................................................78
iList of figures


List of figures

Fig. 1.1 Mechanoreceptors and their location in the skin.......................................................12
Fig. 1.2 Response patterns of the cutaneous mechanoreceptors to skin deformation ..........13
Fig. 1.3 Distribution and density of the Meissner corpuscles (MK) in the foot sole. ...............15
Fig. 1.4 Distdensity of the Vater-Pacini corpuscles (PK) in the foot sole............16
Fig. 1.5 Functional structure of a Meissner corpuscle............................................................17
Fig. 1.6 Structural components of a Vater-Pacini corpuscle ..................................................19
Fig. 1.7 Posterior column-medial lemniscus pathway21
Fig. 1.8 Vibration exciter used to quantify plantar foot vibration sensitivity ............................22
Fig. 1.9 Running shoe and its features...................................................................................26
Fig. 1.10 Subjective ratings for Formula 1 drivers..................................................................27
Fig. 2.1 Vibration thresholds (µm): Baseline vs. cooled measurements ................................39
Fig. 2.2 Vibrolds (µm): Baseline vs. warmed measurements ..............................39
Fig. 2.3 Vibration thresholds at the analysed anatomical locations........................................50
Fig. 2.4 Vibrolds in the analysed pressure conditions. ........................................50
Fig. 2.5 Shoe conditions.........................................................................................................60
Fig. 2.6 Vibration thresholds: Barefoot vs. Shod. Values are means of all anatomical
locations. Shod values are means of the four shoe conditions ..............................................63
Fig. 2.7 Vibration thresholds: frequency comparison. Values are means of all anatomical
locations .................................................................................................................................63
Fig. 2.8 Vibration thresholds at 30 Hz. Shod values are means of the four shoe conditions .64
Fig. 2.9 Vibrolds at 200 Hz. Shod values are means of the four shoe conditions64
Fig. 3.1 Combination of individual factors and their influence on foot sensitivity ...................71
Fig. 3.2 Inovative therapeutic footwear for Diabetes patients ................................................76




iiList of tables


List of tables

Table 1.1 Histological and physiological classification of the cutaneous mechanoreceptors 13
Table 1.2 Distribution of the mechanoreceptors: Comparison of two data collection
techniques..............................................................................................................................14
Table 2.1 Baseline temperatures (°C) prior to skin cooling (PC) and warming (PW).............38
Table 2.2 Baseline threshold differences (cooled-baseline; warmed-baseline) (µm): gender
comparison........38
Table 2.3 Vibration thresholds (µm): men vs. women............................................................49
Table 2.4 Vibration thresholds (µm) of all analysed conditions: mean (SD)...........................62


















iiiList of abbreviations


List of abbreviations

ANOVA.................. Analysis of variance
ISO…….................. International organization for standardization
MET I….................. First metatarsal head
RA I........................ Rapid adaptive receptors with small receptive fields
RA II....................... Rapid adaptive receptors with large lds
S1........................... Formula 1 shoe with common rubber outsole
S2a......................... Formula 1 shoe with decoupled rubber outsole and soft carbon insole
S2b......................... and medium carbon
insole
S2c......................... ber outsole and hard carbon insole
SA I........................ Slow adaptive receptors with small receptive fields
SA II....................... Slow adaptive receptors with large receptive fields
PU.......................... Perfusion units (units of blood flow measurements)
VDT........................ Vibration disappearance thresholds Vibration perception thresholds




ivAbstract


Abstract

The human foot has been accepted over the years as an important source of afferent input,
used not only in the recognition of the surrounding environment (e.g. hard and soft surfaces),
but also in the fine regulation of common daily-live movements (e.g. gait and balance
control). The performance of these movements is usually accompanied by fluctuations in foot
skin temperature as well as reciprocal blood flow changes at the foot area. Moreover, both
variables are likely to be affected by footwear usage. Although these three factors are
constantly present during the performance of daily live movements, only little and partially
controversial information regarding the effects of foot skin temperature, blood flow at the foot
area and footwear on foot sensitivity can be found in the literature. Therefore, the goal of the
thesis was to investigate the effects of foot skin temperature, blood flow at the foot area and
footwear on plantar foot vibration sensitivity of healthy young subjects. Three single studies
were performed in order to investigate each variable separately. The first study investigated
the influence of foot sole skin temperature on plantar foot sensitivity of 40 healthy subjects.
Vibration thresholds were measured at 200Hz at a initial baseline temperature and after
cooling/warming the foot skin 5-6 °C. The second study investigated the influence of short-
time lower leg ischemia on plantar foot vibration sensitivity of 39 young adults. Lower leg
ischemia was evoked with a pneumatic tourniquet, placed about 10cm above the popliteus
cavity. Vibration thresholds were measured at 200 Hz in three different cuff pressure
conditions: baseline (0 mmHg), low (50 mmHg) and high (150 mmHg). Finally, the influence
of footwear on foot sensitivity was investigated in the third study, using specific Formula 1
shoes. Twenty-five male subjects participated in the study. Plantar foot vibration thresholds
were measured at 30 and 200 Hz in five different foot/shoe conditions (barefoot and four
shoe conditions). In all studies, vibration thresholds were measured at three anatomical
locations of the plantar foot: heel, first metatarsal head (MET I) and hallux. The main results
of the three studies show that the analysed variables significantly influence plantar foot
vibration sensitivity. Data from the first study show that 5-6 °C alterations in foot skin
temperature significantly influence the foot sensitivity of healthy young adults, whereby skin
cooling results in reduced foot sensitivity, whereas skin warming improves plantar foot
vibration sensitivity. The results of the second study indicate that short-time lower leg
ischemia; especially regarding the high cuff pressure condition (150 mmhg), significantly
reduces plantar foot sensitivity. Data from the third study show that the footwear effects on
foot sensitivity are frequency-dependent. While barefoot sensitivity is better than shod
sensitivity at 30Hz, shod sensitivity is better than barefoot sensitivity when measured at
200Hz. In conclusion, foot sole skin temperature, blood flow at the foot area and footwear
1Abstract


significantly influence the plantar foot vibration sensitivity of healthy young adults. The
alterations in foot sensitivity caused by these variables have important consequences for
future clinical as well as movement-related research. Future clinical applications of
quantitative sensory testing should consider the influence of these three factors during the
assessment of sensory data, in order to standardize the measurement procedures as well as
to enhance the quality of the collected data. Regarding the movement-related research,
further studies should try to identify the importance of foot sensitivity for the performance of
different types of movements (including sport-related activities). Additionally, the combined
effects of movement-related changes in foot skin temperature and blood flow should be
analysed and integrated in the development process of functional footwear, which is able to
fulffill the foot sensitivity requirements of different movements.






















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