Pedobarography is the study of pressure fields acting between the

plantar Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

surface of the foot and a supporting surface. Used most often for biomechanical analysis of

gait Gait is the pattern of Motion (physics), movement of the limb (anatomy), limbs of animals, including Gait (human), humans, during Animal locomotion, locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on s ...

and posture, pedobarography is employed in a wide range of applications including sports biomechanics and gait biometrics. The term 'pedobarography' is derived from the Latin: ''pedes'', referring to the foot (as in:

pedometer A pedometer, or step-counter, is a device, usually portable and electronic or electromechanical, that counts each step a person takes by detecting the motion of the person's hands or hips. Because the distance of each person's step varies, an ...

pedestrian A pedestrian is a person traveling on foot, by wheelchair or with other mobility aids. Streets and roads often have a designated footpath for pedestrian traffic, called the '' sidewalk'' in North American English, the ''pavement'' in British En ...

, etc.), and the Greek: ''baros'' meaning 'weight' and also 'pressure' (as in:

barometer A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis ...

barograph A barograph is a barometer that records the barometric pressure over time in graphical form. This instrument is also used to make a continuous recording of atmospheric pressure. The pressure-sensitive element, a partially evacuated metal cylinde ...

History

The first documented pedobarographic study was published in 1882 and used rubber and ink to record foot pressures. Numerous studies using similar apparatus were conducted in the early- and mid-twentieth century, but it was not until the advent of the

personal computer A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ...

that electronic apparatus were developed and that pedobarography became practical for routine clinical use. It is now used widely to assess and correct a variety of biomechanical and neuropathic disorders.

Hardware

Devices fall into two main categories: (i) floor-based, and (ii) in-shoe. The underlying technology is diverse, ranging from

piezoelectric sensor A piezoelectric sensor is a device that uses the piezoelectric effect to measure changes in pressure, acceleration, temperature, strain, or force by converting them to an electrical charge. The prefix ''piezo-'' is Greek for 'press' or 'squeeze ...

arrays to light

refraction In physics, refraction is the redirection of a wave as it passes from one transmission medium, medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commo ...

, but the ultimate form of the data generated by all modern technologies is either a 2D image or a 2D image

time series In mathematics, a time series is a series of data points indexed (or listed or graphed) in time order. Most commonly, a time series is a sequence taken at successive equally spaced points in time. Thus it is a sequence of discrete-time data. ...

of the pressures acting under the plantar surface of the foot. Currently, there are several commercial pressure measurement systems and they generally use capacitive or resistive sensors. Studies have shown that capacitive sensors are more valid and reliable than resistive sensors when used continuously for a longer period of time. From these data other variables may be calculated (see

Data analysis Data analysis is the process of inspecting, Data cleansing, cleansing, Data transformation, transforming, and Data modeling, modeling data with the goal of discovering useful information, informing conclusions, and supporting decision-making. Da ...

). There are a few differences between the types of information you will receive from these two systems, so depending on the application one system might be a better fit. For example, a floor-based system will provide spatial temporal information, like stride length that an in-shoe system cannot provide. Platform systems (or floor-based systems) will also allow for testing of patients with walking aids for assistive devices. However, there is some controversy about evaluating natural gait with a platform system due to patients potentially targeting the platform when walking. This is where an in-shoe system provides an advantage as it reduces the risk of targeting. Users should evaluate carefully the differences between the systems, the patients they will be evaluating and the type of data they are interested in when selecting a system. The spatial and temporal resolutions of the images generated by commercial pedobarographic systems range from approximately 3 to 10 mm and 25 to 500 Hz, respectively. Finer resolution is limited by sensor technology. Such resolutions yield a

contact area Contact may refer to: Interaction Physical interaction * Contact (geology), a common geological feature * Contact lens or contact, a lens placed on the eye * Contact sport, a sport in which players make contact with other players or objects * C ...

of approximately 500 sensors (for a typical adult human foot with surface area of approximately 100 cm²). For a stance phase duration of approximately 0.6 seconds during normal walking, approximately 150,000 pressure values, depending on the hardware specifications, are recorded for each step.

Data analysis

To deal with the large volume of data contained in each pedobarographic record, traditional analyses reduce the data to a more manageable size in three stages: (1) produce anatomical or regional masks, (2) extract regional data, and (3) run statistical tests. Results are typically reported in tabular or

bar graph A bar chart or bar graph is a chart or graph that presents categorical variable, categorical data with rectangular bars with heights or lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally. A ...

formats. There are also a number of alternative analysis techniques derived from

digital image processing Digital image processing is the use of a digital computer to process digital images through an algorithm. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing. It allo ...

methodology. These techniques have also been found to be clinically and biomechanically useful, but traditional regional analyses are most common. The most commonly analyzed pedobarographic variable is 'peak pressure', or the maximum pressure experienced at each sensor (or pixel, if the sensors fall on a regular square grid) over the duration of the step. Other variables like contact duration, pressure-time integral, center of pressure trajectory, for example, are also relevant to the biomechanical function of the foot.

Clinical use

The most widely researched clinical application of pedobarography is

diabetic foot A diabetic foot disease is any condition that results directly from peripheral artery disease (PAD) or sensory neuropathy affecting the feet of people living with diabetes. Diabetic foot conditions can be acute or chronic complications of diab ...

ulceration, a condition which can lead to amputation in extreme cases but for which even mild-to-moderate cases are associated with substantial

health care Health care, or healthcare, is the improvement or maintenance of health via the preventive healthcare, prevention, diagnosis, therapy, treatment, wikt:amelioration, amelioration or cure of disease, illness, injury, and other disability, physic ...

expenditure. Pedobarography is also used in a variety of other clinical situations including: post-surgery biomechanical assessment, intra-operative assessment, orthotics design and assessment of drop-foot surgery. In addition to clinical applications, pedobarography continues to be used in the laboratory to understand the mechanisms governing human gait and posture. The use of pedobarographs in clinical settings is supported by researchers. According to Bowen, et al., "Pediobarograph measurements can be used to monitor and quantitatively assess the progressive changes of foot deformity over time. Pedobarograph is a reliable measurement that shows little variability between measurements at the same occasion and between measurements on different days."

Terminology

*''Dynamic pedobarography'' refers to the collection and analysis of time series pedobarographic data during dynamic activities like gait. *''Static pedobarography'' refers to the collection and analysis of time series pedobarographic data during postural (i.e. quasi-static) activities.

References

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diabetic neuropathy Diabetic neuropathy includes various types of nerve damage associated with diabetes mellitus. The most common form, diabetic peripheral neuropathy, affects 30% of all diabetic patients. Studies suggests that cutaneous nerve branches, such as the s ...

. , title = Proc 9th Intl Conf Rehab Robotics , pages = 414–417 , doi = 10.1109/ICORR.2005.1501131 , isbn = 0-7803-9003-2 , s2cid = 47541236 {{cite book , vauthors = Parmar B , year = 2009 , chapter = Assessment of Foot Drop Surgery in Leprosy Subjects Using Frequency Domain Analysis of Foot Pressure Distribution Images. , title = 13th International Conference on Biomedical Engineering, IFMBE Proceedings , volume = 23 , pages = 1107–1111 , doi = 10.1007/978-3-540-92841-6_272 , isbn = 978-3-540-92840-9 Podiatry Walking Anthropometry Biomechanics