Neurological Tests

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Algometry refers to the quantitative measurement of pressure thresholds and pressure tolerances perceived and reported by the patient. The approach is used to help quantity an individual’s pain threshold at designated areas of the body. The Algometer is a device, which has a pressure sensitive tip which can be applied over any body region. The Algometer records the amount of pressure applied, which is correlated to the patient’s perception of pressure and level of discomfort or pain. The findings can be recorded and compared to future responses. 

An audiometric evaluation provides a subjective although quantifiable assessment of hearing integrity. During the procedure a headset or special ear contact device is applied in order to direct tones of varying amplitudes and frequencies into the ear canals. The responses of the participant are recorded and compared to normal and previous values if available. Audiometry is a simple, non-invasive and cost effective method for evaluating for hearing deficits. The approach can be used to monitor a hearing disorder. Some hearing deficits occur as a result of central and/or peripheral neurological disorders. 

The human nervous system has motor, sensory and autonomic components. The autonomic portion of the nervous system controls and regulates internal functions such as blood pressure, blood flow, sweating, bowel function and bladder function. There are a variety of disorders and diseases which can compromise the autonomic nervous system in isolation or as part of more widespread compromise of the nervous system. Chronic pain restricted to one part of the body can lead to autonomic nervous system dysfunction associated with increased sympathetic (autonomic) activity which can magnify pain and alter regional blood flow. 

Autonomic testing is usually non-invasive and generally well-tolerated. The tests and protocols used to assess the autonomic nervous system depend upon the patient’s presentation and suspected condition. Evaluation may involve blood pressure testing under different postural, breathing and exertional conditions. The capacity to sweat in different bodily regions may be assessed. Skin temperature along with digit blood flow may be monitored during a variety of provocative procedures. Electrocardiography (ECG) testing may be used to evaluate heart rate variability during different situations. Ambulatory electrocardiography (AECG) may be performed to evaluate the heart rate, heart rhythm and heart rate variability (R-R intervals) over a prolonged period of time. 

Barognosis, or baresthesia, refers to is the ability to perceive and evaluate the weight of objects, or to differentiate objects of different weights, by holding or lifting them. Accuracy requires an intact and healthy peripheral and central nervous system. The clinical condition referred to as abarognosis or the inability to differentiate between the weights of objects occurs with different types of pathology affecting the nervous system. Accurate Barognosis requires an intact peripheral nervous system, as well as, an intact central nervous system pathway (posterior column-medial lemniscus pathway) to transmit sensations such as light touch, tactile pressure, texture recognition, joint position sense (kinesthesia), and proprioception. Interpretation of sensory stimuli takes place at higher brain levels which must also be intact. 

The test of barognosis often requires that individual be placed in front of a set of small measured and weighted objects which individuals required to place in a particular order. The results of the test are scored. The results may serve as a baseline, as a measure of treatment outcome and/or as a measure of disease progression. Often performed in the clinical setting consists of a series of small measured and weighted objects test for intact barognosis, a set of small objects of the same size and shape but of graduated weight is used. The patient is asked to identify the comparative weight of the objects, i.e. by saying whether the object is "heavier" or "lighter". They may be asked to also place or rearrange objects in a particular order on a table.

Biofeedback refers to the use of special sensors, signal processing technology and some form of feedback to the participant about a bodily reaction to a physiologic state and/or to environmental stimuli. Participant feedback can be used to learn about and to learn to control a bodily function such as breathing quality, breathing rate, heart rate, brain waves and state of muscle tone. 

During biofeedback the participant is typically connected to technology which receives movement, galvanic or electrical stimuli from the body which is processed and turned into practical visual, auditory or sensory stimuli for the participant. Biofeedback may be used during the course of rehabilitation or performance enhancement such as in a sports medicine setting. Biofeedback may also be performed to help overcome stress, manage pain and to improve academic, as well as, cognitive performance. In summary, biofeedback gives the individual the opportunity to develop new ways to adapt to the environment and control their bodies. It also offers new ways to enhance human performance.

Types of biofeedback:

There are many forms of biofeedback. In a healthcare setting feedback may be used to help measure and contribute to therapeutic outcome. The various forms of biofeedback include:

•  Brain waves:  Specialized sensors are used to monitor brain waves as part of an electroencephalograph it (EEG) study. The type, duration and frequence  of brain waves reflect patterns of neural activation and cognitive states.
• Breathing:  Breathing a respiratory biofeedback can be performed by placing sensors      around the abdomen and chest to monitor breathing patterns including the amplitude and rate of respiration.
• Heart rate:  This represents one of the most common forms of biofeedback. Heart rate and rhythm varies considerably during periods of positive and negative stress. It also varies during pre-performance anticipation in athletics. Heart rate sensor may be placed at the end of the finger, on  the earlobe or over the skin in order to evaluate blood volume changes representing the heart rate. A special form of sensor used during the course of this approach is photoplethysmography (PPG). This type uses finger or earlobe sensors with a device used to detect changes in light reflectance which represent blood volume changes.  Specialize electrical sensors can also be placed on your chest, lower torso or wrists use in order to acquire electrocardiograph (ECG) waveforms which can be used to      detect and monitor heart rhythm and rate.
• Muscle      contraction: Specialized superficial sensors are placed over  selected muscle groups. Electrical activity from the underlying muscle isacquired with a specialized device referred to as an electromyograph (EMG) which is used to acquire, analyze and display electrical activity from the muscle. This type of biofeedback can be used to evaluate resting muscle state, the pattern and intensity of muscle contraction as well as the recovery pattern during post-exertional relaxation. This world biofeedback can be used to evaluate the relationships between muscles in different states. It is a common tool used in the fields of sports medicine and sports neurology.
• Sweat gland activity: Special sensors can be applied to the fingers or on your palm or wrist with an electrodermograph (EDG) which is used to measure the activity of your sweat glands and the pattern perspiration on your skin. Sweat gland activity can reflect the level of relaxation, as well as, apprehension and anxiety an individual is experiencing.
• Temperature: Superficial skin temperature often changes with blood flow related to      changes in neurologic regulation of small blood vessel diameter.  Specialized sensors applied the fingers and her toes can be used to measure temperature and related blood flow through the site of measurement. Temperature often drops when in the individuals under extreme stress. A low reading suggests that individual needs to incorporate      various relaxation techniques. Can prompt you to begin relaxation techniques.

A diagnostic cerebrospinal fluid study (CSF) is often referred to as a lumbar puncture. The procedure may be performed to assess the pressure around the brain and spinal cord and to perform biochemical, cellular and immunological tests of the cerebrospinal fluid. Testing the CSF can help reveal the presence of disorders of the central nervous system, which includes the brain or the spinal cord. The evaluation of CSF includes the testing of the number and type of white blood cells, the level of glucose (sugar), the types and levels of proteins, the presence of infectious organisms, the quantity of certain antibodies, and the presence of biochemical tumor markers.

Gait analysis refers to the evaluation of posture and movement patterns while walking or jogging. Gait analysis is used to evaluate the complex integration of neurological and musculoskeletal performance. It may be performed using a specialized treadmill allowing for variable manipulation such as speed and incline. Gait analysis can provide valuable information about postural control which involves spinal cord function, peripheral nerve function, vision, balance involving the inner ear, and control from the brainstem and higher cortical (brain) centers. Gait analysis can also be particularly helpful in the assessment of muscle weakness and associated movement disorders secondary to central and/or peripheral nervous system disorders. The use of a variable speed treadmill can help detect gait abnormalities that would not be readily obvious while watching the patient walk a short distance at a slow pace during the course of a traditional physical examination.

Isokinetic testing is usually performed as part of a more comprehensive assessment of physical performance. It typically involves placing a patient on specialized equipment so that the specific body and joint movements can be isolated and measured. The equipment is set at different speeds and the force applied is measured throughout the range of movement. The results are typically recorded at different speeds so that a speed/strength/power relationship can be seen. Comparative evaluation of muscle strength and power can be performed with side-to-side assessment and with ipsilateral agonists/antagonists assessment. The equipment is often large, bulky and expensive; subsequently, these tests are often performed with large healthcare or university settings.

Isokinetic testing can be used to evaluate impairment of muscle function secondary to central, spinal or peripheral nerve compromise. Quantitative measures can be used to baseline physical performance. Isokinetic testing can also be used to help assess neurological and neuromuscular recovery..

Motion analysis is used in a neurology setting to evaluate human movement under various circumstances. This form of testing helps evaluate the integrity of the neurologic control of muscle and the neurological feedback systems required to perform purposeful acts and to quickly adapt to environmental stimuli. Motion analysis often involves integration of computer vision, image processing, high-speed photography and computational analysis. Video measures of motion may also be used to provide feedback to a patient or athlete in a specialized setting. Visual data is often acquired through the use of the specialized high-speed camera or video camera. The data is then analyzed using special software and digital metrics. Motion analysis may be performed in a clinical setting are on the athletic field. In the case of sports medicine application motion analysis data may be evaluated by clinical specialists, as well as, experts in the sport field. 

Various types of spine injections or nerve blocks can sometimes be performed to help diagnose or identify the primary source of spine (back) pain. Spinal nerves and nerve roots can become inflamed and painful for a variety of reasons. Sometimes nerve compromise occurs secondary to obvious structural problems but in other cases there may not be imaging confirmation of nerve compression or nerve inflammation. A series of carefully targeted injections can sometimes help diagnosis or treat a spine disorder. 

Specialized forms of nerve injections or blocks include: 

• Epidural Block: This is a spinal block performed under fluoroscopy (X-ray guidance). A local skin anesthetic is applied. A spinal needle is then inserted into the epidural space of the spinal canal. The combination of an anesthetic agent and a steroid may be administered. The approach may result in less pain and in a reduction of related signs and symptoms. A favorable response may be temporary. 

• Selective Nerve Root Block: This refers to a block performed under fluoroscopy (x-ray guidance). The injection of an anesthetic agent and steroid is administered into the epidural space near a specific nerve root. If the involved area is reached the approach may lead to a reduction of nerve pain and other related symptoms. A favorable response may be temporary. 

• Facet Block (Medial Branch Block): This is a block used to confirm whether a facet (spinal) joint is the primary source of pain. A local anesthetic agent is administered to the skin. A needle is then inserted into the facet joint or near a nerve which innervates (connects to) d the facet joint. An anesthetic agent and steroid is often injected by the attending physicians. The procedure is performed under fluoroscopy (x-ray guidance). The procedure is often consider a success if there is a significant reduction. The produce may be performed a total of two to three times. A favorable response may be temporary. 

• Costovertebral Joint Block: This is a block performed under fluoroscopic guidance (x-ray guidance) to help determine whether there is pain arising from a costovertebral joint. A local anesthetic agent is applied. A needle is placed in the area of the costovertebral joint and typically an anesthetic agent and steroid is injected. A favorable response may be temporary. 

• Sympathetic Nerve Block: This is a block, which is administered to help identify whether there is damage to the sympathetic nerve chain and whether it is contributing to pain. The procedure is performed by inserting a needle into the back under the guidance of fluoroscopy (x-ray guidance). The needle tip is placed next to the vertebral body. The block may be performed on either side of the spine. An anesthetic agent is administered to the area. A favorable response may be temporary. 

Nerve conduction studies (NCS) are typically performed along with a needle electromyographic examination. Collectively the approach may be referred to as a “nerve study” or “electrodiagnostic test”. The test is used to localize, qualify and quantify nerve involvement.

To perform the test superficial electrodes are placed upon the skin over the known course of a nerve. The nerve is stimulated at a designated spot with a handheld device, which produces a small electrical current. The application of a stimulus initiates the propagation of nerve impulses, which are recorded at the electrode site and transferred to a computer for recording and analysis. The study can be used to detect the strength of the nerve signal, the quality of the nerve signal and the speed of the nerve signal transmission between designated points along the course of a nerve. NCS studies provide a valuable non-invasive method for monitoring and re-evaluation of a region of neurological compromise. The results of nerve conduction studies can help direct precise therapeutic intervention including surgery.

When there is neurological compromise there is often some degree of related physical dysfunction or physical impairment corresponding to the site and degree of compromise. Neuro-orthopedic (neuromuscular) assessment addresses the relationship between the nervous system and the musculoskeletal system as it relates to movement, adaptation and reaction to the environment. One of these approaches is referred to as a selective neuromuscular functional capacity evaluation (SNFCE). The SNFCE examination is comprised of a combination of tests referred to as a profile which is used to objectify and quantify sensibility, range of motion, coordination, strength, endurance and integrated physical performance as it relates to a confirmed site of neurological compromise. Different categories of testing is listed below:

• Psychometric Functional Assessment: This approach involves the use of one or more condition (disease) specific questionnaires to score perceived physical capabilities.

• Selective Neuromuscular Functional Capacity Evaluation: Profiled physical performance measures/tests grouped in accordance with the level of known neurologic or muscular compromise. 

• Balance and Gait Assessment: Profile of physical performance measurements used to assess a patients coordination, balance and walking efficiency (gait). This may involve the use of a quantitative treadmill, computer-controlled balance platform and/or force plate.

• Quantitative Sensory Testing: Quantitative sensory testing is performed to assess and baseline sensation for the purpose of monitoring a disease process and measuring a disease process or therapeutic outcome. Sensory measurements may include light touch, position sense, pain, temperature, vibration, barognosis, and two point discrimination (static and moving).

• Virtual Realty Assessment: Application of the leading-edge technology to assess neurological integrity and to assess human performance and response to virtual stimuli. This represents an advanced form of neurorehabilitation. The study is achieved by immersion of the patient into a virtual environment often with the use of a special headset. Customers have questions, you have answers. Display the most frequently asked questions, so everybody benefits.

Somatosensory evoked potential studies (SSEP or SEP) are helpful in the evaluation of large diameter sensory nerve compromise. The studies can be used to measure the quality, speed and strength of sensory nerve transmission through the peripheral nerve, the plexus, the spinal nerve, spinal cord, brainstem and specific areas of the brain. The sensory nerve signal transmission across a site of compromise may be slowed, altered in quality and/or diminished in strength. SSEP studies may be used to monitor spinal cord and spinal nerve root and quality during spinal surgical procedures. 

Evoked potentials are electrical manifestations of the brain’s response to external stimuli. Interpretation of somatosensory evoked potentials is based upon measures of nerve transmission speed (latency) and amplitude. Evoked potentials studies performed at CNI include:

• Visual Evoked Potential (VEP): Visual evoked potential studies (VEP) are used to evaluate the integrity and function of central visual pathways extending from the retina/optic nerve to the occipital lobe of the brain. The VEP study is very helpful in the assessment of neurological disorders associated with vision problems.

• Dermatomal Somatosensory Study (DSEP): This study refers to the electrical assessment of the sensory fibers of specific spinal nerve roots and spinal cord pathways.. Most nerves which exit the spine contain sensory nerve fibers which connect to and innervate specific skin and other soft tissue regions. Innervated areas of skin are referred to as dermatomes. The DSEP study is performed by placing superficial stimulating electrodes over a skin area innervated by a spinal nerve, to be tested. Superficial recording electrodes are placed over the spine and brain regions. The nervous system response to stimuli is recorded over the spine and/or scalp. Measurable nerve signal attributes include the speed of nerve conduction, the strength of the evoked thalamus/brain response, and the quality of nerve signal transmission. 

                        The DSEP study is often performed after the EMG/NCV study if the former is unrevealing in a     

                        patient believed to have spinal nerve root compromise. Nerve root compromise is more often 

                         associated with sensory complaints with muscle weakness typically occurring later secondary 

                         to progressive nerve damage. Subsequently, a DSEP assessment can sometimes provide 

                         greater insight than the more traditionally used needle EMG study to confirm and localize the 

                         level of mild nerve root compromise (radiculopathy). A needle electromyographic study will not 

                         reveal radiculopathy (spinal nerve ) compromise limited to sensory involvement. The study can  

                         also help detect spinal cord compromise. 

• Brainstem Auditory Evoked Potential (BAER): The BAER measures the integrity and function of the auditory nerve (peripheral nerve), as well as, the central pathways of hearing. Signals are recorded as they pass through different levels of the brainstem and the brain. The study can be helpful in the localization of a focal lesion along the neurological pathways of hearing. 

Spine palpation refers to the application of the hand(s) or fingers on the surface of the body for the purpose of evaluating the condition of the spine. Palpation is defined as the act of feeling with the hands. A skilled physician can derive a lot of information through careful and methodical palpation of an area of interest. It involves the application of manual methods applied through the surface of the body to assess the shape, size, consistency, movement patterns and general health of bodily regions and tissues. Palpation represents one of the oldest forms of physical examination. Palpatory skills are learned tasks that require hours and often years of devotion and practice to fully develop. 

Spinal palpation is a practical and cost efficient diagnostic procedure, which can be applied to the back (spine) during the course of an office visit. Palpatory examination often provides diagnostic information, which cannot be obtained through X-ray, or other advanced imaging techniques. Palpation can be used to assess temperature variations, muscle tension patterns, reactive muscle spasm, joint mobility, muscle atrophy, tumors /masses and swelling.

Palpation can be divided into static and dynamic categories. Static palpation refers to manual assessment with the patient or a bodily region lying in a stationary position. The static category of palpation can be further divided into bony and soft tissue palpation. Dynamic or motion palpation is particularly helpful for evaluating joint mobility which includes the assessment of joint play, joint end play, end feel and reactive paraspinal muscle spasms, all of which, may accompany painful movement. Motion palpation of the spine is used to diagnosis the pattern of passive and active spinal segmental movement.

Stereopsis evaluation is used to screen vision, more specifically to assess an individual’s ability to fuse their eyes on one location. Successful visual fusion also referred to as intact binocular vision is required for depth perception. The stereopsis evaluation is a helpful test for ruling out eye muscle imbalance secondary to muscle disease, motor neuron disease and due to disorders of the central or peripheral nervous systems.  

The tilt table study is often used to evaluate patients who have had syncope (loss of consciousness) or near-syncope (near loss of consciousness). It is an extremely simple study, and in most cases quite safe. A tilt table study is performed with the patient strapped to a table, which is then mechanically tilted to a predetermined upright position. 

The table is tilted while monitoring an individual’s pulse, blood pressure, electrocardiogram, and sometimes blood oxygen saturation. The patient may be left in a “motionless standing position” for 20 to 30 minutes. When the patient's syncope is reproduced during the test, a "positive" tilt table study is said to have occurred. 

During an upright tilt and while standing a person's cardiovascular system has to adapt to main adequate vascular perfusion and to prevent a significant portion of blood volume from pooling in the legs. These adjustments consist of a mild increase in heart rate, and a constriction of the blood vessels in the legs. When a normal individual is placed in an upright tilt, these cardiovascular adaptations occur very quickly, and there is no significant drop in the blood pressure. In patients with neurological conditions such as orthostatic hypotension and vasovagal syncope, the autonomic nervous system regulation of the cardiovascular response does not work right..

The tilt table study is often used to evaluate patients who have had syncope (loss of consciousness) or near-syncope (near loss of consciousness). It is an extremely simple study, and in most cases quite safe. A tilt table study is performed with the patient strapped to a table, which is then mechanically tilted to a predetermined upright position. 

The table is tilted while monitoring an individual’s pulse, blood pressure, electrocardiogram, and sometimes blood oxygen saturation. The patient may be left in a “motionless standing position” for 20 to 30 minutes. When the patient's syncope is reproduced during the test, a "positive" tilt table study is said to have occurred. 

During an upright tilt and while standing a person's cardiovascular system has to adapt to main adequate vascular perfusion and to prevent a significant portion of blood volume from pooling in the legs. These adjustments consist of a mild increase in heart rate, and a constriction of the blood vessels in the legs. When a normal individual is placed in an upright tilt, these cardiovascular adaptations occur very quickly, and there is no significant drop in the blood pressure. In patients with neurological conditions such as orthostatic hypotension and vasovagal syncope, the autonomic nervous system regulation of the cardiovascular response does not work right.

Virtual reality testing refers to the measurement of human performance and their response to stimuli in a lab using sophisticated equipment. The stimuli may include immersing the patient in a predetermined virtual environment to measure their response and ability to adapt to visual, touch and/or auditory stimuli. Sophisticated technology and related protocols are used to record and analyze responses. A good example of VR simulation and testing is the simulated flight station, which pilots train on. At these computerized workstations individuals are exposed to a variety of circumstances and their response patterns and related performance outcomes can be recorded and analyzed to reveal deficits and/or improvement. Virtual reality testing in a clinical setting can be used to determine whether an individual is a candidate for neurorehabiliation or sport specific training.