Posturography
Encyclopedia
Posturography is a general term that covers all the techniques used to quantify postural control in upright stance in either static or dynamic conditions. Among them, Computerized dynamic posturography (CDP), also called test of balance (TOB), is a non-invasive specialized clinical assessment technique used to quantify the central nervous system
adaptive mechanisms (sensory
, motor
and central) involved in the control of posture
and balance, both in normal (such as in physical education
and sports training) and abnormal conditions (particularly in the diagnosis
of balance disorder
s and in physical therapy
and postural re-education). Due to the complex interactions among sensory, motor, and central processes involved in posture and balance, CDP requires different protocol
s in order to differentiate among the many defects and impairments which may affect the patient's posture control system. Thus, CDP challenges it by using several combinations of visual and support surface stimuli and parameters.
Clinical applications for CDP were first described by L.M. Nashner in 1982, and the first commercially available testing system was developed in 1986, when NeuroCom International, Inc., launched the EquiTest system.
s), which are able to detect the tiny oscillations of the body.
Dynamic posturography differentiates from static posturography generally by using a special apparatus with a movable horizontal platform. As the patient makes small movements, they transmit in real time
to a computer
this time-varying information. The computer is also used to command electric motor
s which can move the forceplate in the horizontal direction (translation) as well as to incline it (rotations). Thus, the posturography test protocols generate a sequence of standardized motions in the support platform in order to desequilibrate the patient's posture in an orderly and reproducible way. The platform is contained within an enclosure which can also be used to generate apparent visual surround motions. These stimuli are calibrated relative to the patient's height and weight. A special computer software integrates all this and produces detailed graphics and reports which can then be compared with normal ranges.
The test protocols usually include a Sensory Organization Test (SOT), a Motor Control Test (MCT) and an Adaptation Test (ADT). Minute spontaneous body sways are measured as well as reactions provoked by unexpected abrupt movements of the platform and the visual surroundings.
According to necessity of the diagnostic workup, CDP can be combined with other techniques, such as electronystagmography
(ENG) and electromyography
.
The main indications for CDP are dizziness
and vertigo
, and postural imbalances (balance disorder
s).
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
adaptive mechanisms (sensory
Sensory system
A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic...
, motor
Motor system
The motor system is the part of the central nervous system that is involved with movement. It consists of the pyramidal and extrapyramidal system....
and central) involved in the control of posture
Human position
Human positions refers to the different positions that the human body can take.There are several synonyms that refer to the human position, often used interchangeably, but having specific flavors....
and balance, both in normal (such as in physical education
Physical education
Physical education or gymnastics is a course taken during primary and secondary education that encourages psychomotor learning in a play or movement exploration setting....
and sports training) and abnormal conditions (particularly in the diagnosis
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...
of balance disorder
Balance disorder
A balance disorder is a disturbance that causes an individual to feel unsteady, for example when standing or walking. It may be accompanied by feelings of giddiness or wooziness, or having a sensation of movement, spinning, or floating...
s and in physical therapy
Physical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
and postural re-education). Due to the complex interactions among sensory, motor, and central processes involved in posture and balance, CDP requires different protocol
Clinical trial protocol
A clinical trial protocol is a document that describes the objective, design, methodology, statistical considerations, and organization of a clinical trial...
s in order to differentiate among the many defects and impairments which may affect the patient's posture control system. Thus, CDP challenges it by using several combinations of visual and support surface stimuli and parameters.
Clinical applications for CDP were first described by L.M. Nashner in 1982, and the first commercially available testing system was developed in 1986, when NeuroCom International, Inc., launched the EquiTest system.
How it works
Static posturography is carried out by placing the patient in a standing posture on a fixed instrumented platform (forceplate) connected to sensitive detectors (force and movement transducerTransducer
A transducer is a device that converts one type of energy to another. Energy types include electrical, mechanical, electromagnetic , chemical, acoustic or thermal energy. While the term transducer commonly implies the use of a sensor/detector, any device which converts energy can be considered a...
s), which are able to detect the tiny oscillations of the body.
Dynamic posturography differentiates from static posturography generally by using a special apparatus with a movable horizontal platform. As the patient makes small movements, they transmit in real time
Real-time computing
In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...
to a computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
this time-varying information. The computer is also used to command electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
s which can move the forceplate in the horizontal direction (translation) as well as to incline it (rotations). Thus, the posturography test protocols generate a sequence of standardized motions in the support platform in order to desequilibrate the patient's posture in an orderly and reproducible way. The platform is contained within an enclosure which can also be used to generate apparent visual surround motions. These stimuli are calibrated relative to the patient's height and weight. A special computer software integrates all this and produces detailed graphics and reports which can then be compared with normal ranges.
The test protocols usually include a Sensory Organization Test (SOT), a Motor Control Test (MCT) and an Adaptation Test (ADT). Minute spontaneous body sways are measured as well as reactions provoked by unexpected abrupt movements of the platform and the visual surroundings.
According to necessity of the diagnostic workup, CDP can be combined with other techniques, such as electronystagmography
Electronystagmography
Electronystagmography is a diagnostic test to record involuntary movements of the eye caused by a condition known as nystagmus. It can also be used to diagnose the cause of vertigo, dizziness or balance dysfunction by testing the vestibular system....
(ENG) and electromyography
Electromyography
Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...
.
The main indications for CDP are dizziness
Dizziness
Dizziness refers to an impairment in spatial perception and stability. The term is somewhat imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness....
and vertigo
Vertigo (medical)
Vertigo is a type of dizziness, where there is a feeling of motion when one is stationary. The symptoms are due to a dysfunction of the vestibular system in the inner ear...
, and postural imbalances (balance disorder
Balance disorder
A balance disorder is a disturbance that causes an individual to feel unsteady, for example when standing or walking. It may be accompanied by feelings of giddiness or wooziness, or having a sensation of movement, spinning, or floating...
s).