Debatably, the clinical neurological examination is the least effective test for all but the most severe cases of traumatic brain injury. The usual clinical approach to the study of brain function is the neurological examination. This includes a study of an individual´s "behavior" which comprises responses and motor patterns.

The neurologist examines an individual´s reactivity, his/her strength, the appropriateness of the individual´s reaction to commands, questions, and other inquiries, and challenges to muscle groups. The neurologist examines the body, in general, looking for evidence of brain dysfunction that maybe evidenced through atrophied muscles, or due eye or retina deformation. When looking at behavior, the neurologist looks at patterns in gross terms. In short, if the neurologist can´t "see it", or "feel it", the conclusion is often reached that "it does not exist".

One need not be an expert in traumatic brain injury to understand the extremely limited benefit of a standard neurological examination in cases involving mild to moderate traumatic brain injury. In fact, most individuals sustaining mild to moderate traumatic brain injury have virtually normal findings on clinical neurological exam.

Often times administered by EMT personnel or paramedics during ambulance transport from the scene of an accident, the Glasgow Coma Scale rates

• a patient´s ability to open his/her eyes;
• motor responses to verbal/painful stimulus;
• verbal responses.

The Glasgow Coma Scale is also used to rate coma victims, and an individual´s response, or lack thereof, may correlate, especially in severe cases, to cognitive deficits. Where the patient´s consciousness has been compromised, the Glasgow coma scale has proved effective for determining severity of injury. As indicated earlier, however, problems can arise where the victim is found to be under the influence of either pain medication or alcohol at the time of administration of the test.

When evaluating injury severity, a GCS range of 3 to 8 is considered severe, 9 to 12 is moderate and 13 to 15 is mild. Coma has been defined as occurring when the GCS is equal to or less than 8.

As indicated above, the GCS creates a score on a continuum ranging from a minimum of three to a maximum of 15 points. Presumably, an individual can have a mild traumatic brain injury and yet still score 15 on the GCS. This is why the American Congress of Rehabilitative Medicines definition of mild traumatic brain injury allows for a GCS of 13 to 15. The GCS has been criticized by many, therefore, is having much more efficacy in the diagnosis of moderate to severe traumatic brain injury then in the diagnosis of mild traumatic brain injury.

Studies show that patients with a lower GCS score show poorer prospects for recovery. This is another important use of the GCS. Not only is the GCS used to evaluate severity, but it is also used as a predicting tool to determine outcome. Moreover, it can be used repeatedly over time as a prognosticating tool.

A complement to the GCS is the Glasgow Outcome Scale (GOS). The GOS provides five levels for evaluating outcome. The first is that of death due to brain damage. Generally speaking this will happen 48 hours after injury. The second is persistent vegetative state (PVS). The third is described as severe disability, which implies consciousness though individuals are dependent for daily support. The fourth state is described as moderate disability, which implies that the patient is disabled but is independent. The fifth state is described as good recovery, which implies a resumption of normal life. Note that the fifth state does not prognosis a return to the competitive workplace, however.

Criticism of the GOS primarily emanates from its simplicity. Individuals often cannot be categorized within the five listed categories. Discussion has occurred over time within the health care profession of expanding the five categories to eight, but even with eight listed categories, criticism exists.

  While the GCS has been universally accepted as a standard measure for determining severity of injury in patients whose consciousness is comprised, it also has some inherent problems. Mentioned above are problems where the patient has been sedated or where the patient has been anesthetized or were intubated as a result of injury. Where any type of medical treatment results in the patient being unable to talk (such as a tracheotomy), or where the patient is unable to move limbs as a response to pain, the GCS will obviously be limited.

Levels of Cognitive Functioning This scale describes levels of function and is used to evaluate the progress of a patient and rehabilitative development. Most often, the "Rancho scale" is used to track improvement, for evaluating potential, for planning and placement purposes, and to measure outcome and treatment effects.

In essence, the Rancho scale measures eight levels of cognitive function. The scale was primarily developed for use by rehabilitation staff, and contemplates a course of improvement following head trauma. The eight levels of cognitive functioning of the Rancho scale are as follows:

• No response: (such as where the patient is in a deep coma).
• Generalized response: (inconsistent reaction and non-purposeful response to stimuli).
• Localized Response: inconsistent though specific reaction to stimuli or even following simple commands).
• Confused-Agitated: (patient has decreased ability to process information but is in a heightened state of activity).
• Confused, Inappropriate, Non-agitated:(patient is able to respond fairly consistently to simple commands and appears alert, though with increased complex city of commands a fragmented response is shown).
• Confused-Appropriate: (goal-directed behavior is evident but the patient is dependent on assistance).
• Automatic-Appropriate: (within the hospital and home settings the patient is oriented and able to follow a daily routine with minimal confusion but has shadow recall of activity).
• Purposeful and Appropriate: (patient is alert, oriented, recall is intact, and patient is aware of responsive to environment).

Criticism of the Rancho scale is that the scale is not sensitive to differences in levels of vocational potential and, as above, this scale implies a similar rate of improvement for different kinds of functions which may, or may not, be the case in each individual´s recovery.

Clinicians most often use the GOAT to assess more severely or moderately impaired patients. In essence, this test is a short mental status examination. It can be repeated as with the GCS. The vast majority of the questions on this test involve whether the patient is oriented as to time, place, and person. Two questions deal with anterograde and retrograde amnesia. The GOAT is used to predict ultimate recovery in a patient and is also used as an indicator of level of responsivity.

The measurements obtained using the GOAT questions dealing with anterograde and retrograde amnesia establishes the relationship between severity of injury (GCS), and a patient´s long-term outcome (GOS).

This test was designed for measuring the duration of post traumatic amnesia and tests memory, demographics, and orientation. Each day, the patient is tested as to his/her memory and ability to recall and recollect. When the patient is able to score a perfect score 3 days in a row, the test is concluded.

Different scales have evolved out of the Oxford Test. Different scales can be used to determine recovery and duration, thereby charting improvement on different components of orientation and memory.

Neuropsychological testing is the sine qua non for modern diagnostics of brain injury. It is proven reliable, accurate, and unlike other testing and evaluative mechanisms which compare patients with the so-called "normal person", neuropsychological testing evaluates whether a particular patient has himself/herself changed.

The rationale for this distinction is easily enunciated: As an individual grows and matures, s/he develops and utilizes the most efficient pathways in the brain. When traumatic brain injury occurs, many times those pathways are severed or unable to properly transmit or receive information. Methods of learning and behaving are altered. While this individual may still be within the normal population range, s/he would surely be outside their individual "pre-injury" range.

Neuropsychological testing allows competent professionals to reach the conclusion, to a reasonable degree of scientific probability, that organic brain injury has occurred. It further allows the professionals to pinpoint areas of deficit, be they visual/spacial, memory, recall or other. Simply put, neuropsychological testing is the most important testing most "mild" to "moderate" traumatic brain injury patients will undergo.

Neuropsychological assessment is a method of validation, which measures the ability of the nervous system to perform cognitive functions we minimally need to exist. It measures compromise of functions against pre-morbid capabilities. Neuropsychologists are psychologists with specialized training. Neuropsychological assessment is an interface between science and practice.

A current debate in the field of Neuropsychology focuses primarily on approach. Many neuropsychologists advocate the quantitative approach utilizing the so-called "non-flex" Halstead-Reitan battery of testing. Still others advocate the "flexible battery" approach. Statistical accuracy is the issue. In a 2000 survey, it was found that only 15% of the neuropsychologists surveyed used a fixed battery (the Halstead Reitan or Lurie-Nebraska batteries).

Clearly, there are advantages and disadvantages to use of either a fixed battery or a flexible battery approach. Utilization of a non-flex battery can reveal objective data in as much as it is gathered without subjective influence and all scores are subjected to the same variables. However a fixed battery does not allow the clinician the freedom to address specific diagnostic problems. The flexible battery does give the clinician the opportunity to individually test and assess for certain problems which may be present though missed under the non-flex approach.

Irrespective of approach, neuropsychological assessment is essential to the proper diagnoses and treatment of most victims of traumatic brain injury. Neuropsychological assessment batteries are utilized in order to obtain an accurate diagnoses of the individual (though with the improvement of neuro- imaging, discussed below, utilization of assessment batteries for diagnostic purposes is not as important today as it was in the past). Primarily then, neuropsychological assessment batteries are utilized in order to obtain and determined a functional assessment of the particular patient. Numerous formalized batteries have been developed for general use while others were "personalized" to assess a specific need. There are literally thousands of tests available to the neuropsychologist depending upon the issues faced. In essence, it is the incumbent upon the neuropsychologist to derive a battery that provides for an examination appropriate to the given patient. Tests that may be utilized by a neuropsychologist may include, among others, the following:

• Halstead-Reitan Battery;
• Halstead Russell Neuropsychological Evaluation;
• Repeatable Cognitive-Perceptual-Motor Battery (Lafayette Clinic Repeatable Neuropsychological Test Battery);
• Luri-Nebraska Neuropsychological Battery;
• Neuropsychological Assessment Battery;
• Kaplan-Baycrest Neurocognitive Assessment;
• Wechsler Intelligence Scales;
• Peabody Individual Achievement Test;
• The Kaufman Brief Intelligence Test;
• Wide Range Achievement Test;
• Woodcock Johnston Tasks of Cognitive Ability;
• Stanford-Binet Intelligence Scale;
• Iowa Screening Battery for Mental Decline;
• Assessment of Individuals with Cognitive Impairment;
• San Diego Neuropsychological Test Battery;
• Repeatable Battery for the Assessment of Neuropsychological Status;
• Cambridge Cognitive Examination;
• Mini-Mental Status Examination;
• Disability Rating Scale;
• Katz Adjustment Scale;
• The Mayo-Portland Adaptability Inventory;
• Beck Depression Inventory;
• Thematic Apperception Test;
• Rorschach Test;
• The Zung Self-rating Depression Scale;
• Million Clinical Multi-axial Inventory;
• Minnesota Multiphasic Personality Inventory (MMPI/MMPI-2);
• Personality Assessment Inventory;
• General Memory versus Attention/Concentration;
• Auditory-Verbal Learning Test;
• California Verbal Learning Test;
• Complex Figure Test;
• Recognition Memory Test;
• Memory Assessment Scales;
• Wisconsin Card Sorting Test;
• Paste Auditory Serial Addition Test (PASAT);
• Reaction Time (RT);
• Forced-Choice Test;
• Portland Digit Recognition Test;
• Hopkins Recall/Recognition Test;
• Test of Memory Malingering (TOMM);
• Validity Indicator Profile (VIP);
• Word Memory Test (WMT);
• Rey 15-Item Test;

Obviously, there are hundreds of additional tests which may, under the circumstances of an individual case, be utilized by an appropriate neuropsychologist. Counsel representing individuals with traumatic brain injury must be familiar with the general tests given, the test purpose, the test parameters, and the methodology employed in grading any such test.

Clearly the most exciting area of advancement in the diagnosis of traumatic brain injury involves neuro imaging. At its most basic, neuro imaging covers two broad categories: (1) brain structure; and (2) brain function.

Analyzing brain structure is very different from analyzing brain function. When looking at brain structure, it is the anatomy of the brain that is analyzed. In order this point be understood, were an individual who immediately died be placed in a scanning device which looks only at brain structure, and lest significant deterioration of the brain immediately occurred, one could expect the scan to be read as "normal". (This to be compared to a devise scanning for brain function which obviously would demonstrate "no function", thus extremely abnormal).

However, were there to be a trauma to the brain itself, which trauma caused bleeding within the skull, or contusions to the brain, or bleeding within the skull cavity, then a devise measuring brain structure could be expected to show the abnormality, depending on amount of damage.

Tests analyzing brain function are not nearly as concerned with the actual structural environment of the brain as much as they are concerned with brain function it self. We first discuss those devices or tests which analyze brain structure:

Some of the imaging tests which analyze brain structure include the following:

• Skull X-Ray;
• Computed Tomography (CT);
• Magnetic Resonance Imaging (MRI);
• Diffusion Tensor Imaging (DTI);
• Magnetization Transfer Imaging (MTI);
• Magnetic Resonance Spectroscopy (MRS);
• Magnetic Source Imaging (MSI);

Given that most individuals are familiar with basic x-ray, discussion herein is limited to the other scanning methods.

Since its introduction in approximately 1973, computed tomography (CAT, or CAT computed axial tomography) has developed quickly. A series of collimated x-ray beams through the tested body and measurement of the extent of tissue absorption is made. CT is demonstrative of collections of blood (hematomas), cerebral contusions (bruises), edema (swelling), as well as basal skull fractures.

MRI is a diagnostic procedure which examines body tissue by subjecting the atomic nuclei of the tissues to a magnetic field. The atomic nuclei of the tissues are stimulated by the field. Bad tissue responds differently than good.

In recent years, huge advances have occurred with respect to MRI. Up until approximately 2000, most neuro imaging centers maintained MRI machines with Tesla field strength 1 to 1.5 magnets. As of recent, the FDA has approved Tesla field strength 3 magnets for human use. With the use of Tesla field strength 3 magnets, lesions are now being seen on MRI that were impossible to detect on the earlier MRI scanners using lesser field strength magnets. Advancements in software utilized by the MRI scanners have likewise improved their diagnostic capability.

Where head injury is concerned, Gradient Echo software has proved extremely valuable. Many teaching institutions are now experimenting with field strength magnets as high as Tesla 10. It is expected that with the advances in MRI technology, even extremely mild traumatic brain injury patients will have demonstratively viewable abnormality on MRI.

An example of this was capitalized on by the Scarlett Law Group during the case of Rasmussen versus Shade. Mr. Rasmussen had been rear ended while in stopped traffic in Northern California. There was less than $500 damage to the rear bumper of Mr. Rasmussen´s vehicle. Nonetheless, Mr. Rasmussen sustained a traumatic brain injury.

Following the accident, imaging was done on a T-1 magnet strength MRI scanner in the Sacramento area. The MRI scanner was read as "normal". Several months later, imaging was again done on the T-1 scanner. It too was read as "normal".

After contacting the Scarlett Law Group, treating physicians ordered a repeat MRI, but this time utilizing a T-3 scanner. Two focal lesions in the anterior and posterior frontal lobes were immediately seen. Given the coup/contra coup pattern of the lesions, and further given their presence at the juncture of the grey/white matter of the brain, diagnoses of traumatic brain injury was conclusively made.

What is unique about this is that in utilizing the lesser strength scanner, the lesions were not read on the film. However, after looking at the T-3 film, and comparing it to the film derived from the lesser strength MRI scanner, the abnormalities of the lesions could be vaguely made out. In other words, no one could have been critical of the earlier readings of the film from the lesser strength scanners as the lesions were not readily apparent. However, with the benefit of the T-3 film, the abnormalities could be seen on the earlier scans though not with the absolute clarity of the T-3 film.

Where head injury is concerned, it is thought that the admission of the T-3 film into evidence in the Rasmussen versus Shade case is the first time a California court (and jury), has had the benefit of said technology. It is expected to be the norm in years to come.

Diffusion tensor imaging is an MRI application that utilizes the diffusion of water model molecules for imaging the brain. DTI not only measures the diffusion of water molecules in a particular direction, but can analyze by imaging diffusion in as many as six or more directions. This allows for a three dimensional matrix or calculation of "tensor". Structural integrity in the white matter of the brain can be measured as water diffusion is higher along fiber tracks then across them.

Magnetization transfer imaging (MTI) is another technique that increases the contrast between tissues by exploiting the exchange of protons between water and macromolecules. A radio frequency pulse selectively saturates protons that are bound to macromolecules in the brain. MTI provides information about tissue changes not detected by T1 or T2 MRI. MTI has yet to be extensively used in the area of traumatic brain injury.

Magnetic Resonance Spectroscopy detects signals from individual solutes in body tissues thereby offering neuro chemical information about the brain. MRS is generally used to assess metabolic irregularities following brain injury. It is based on measuring magnetic signals from certain nuclei in response to radiofrequency pulses. MRS correlates well with neuropsychological functioning and functional outcome tests.

Magnetic source imaging (MSI) utilizes magnetoencephalographic technology to acquire electrophysiological data from the brain and combine it with structural data from conventional MRI technology. MSI technology is new. It holds hope in the diagnoses of mild TBI patients with post-concussive syndromes.

Generally speaking, structural imaging is extremely helpful in cases involving skull fractures as well as hematomas, or hemorrhages which may occur at a variety of locations in the brain.
Common hematomas include:

1. Epidural Hematomas - This injury forms when the brain´s outer covering, or dura, is stripped away from the skull by blood from lacerated blood vessels or bleeding from a fracture. The injury generally occurs over the temporoparietal area but can also occur in the frontal lobes as well as the other areas of the brain.
2. Subdermal Hematomas - This injury forms in the space between the dura and brain, often produced by torn veins on the brain surface and the inside edge of the dura matter. This injury may develop within the first 24 hours of insult, but and develop up to two weeks are after insult.
3. Intracerebral Hematomas - This injury forms within the substance of the brain and often results from a laceration. Often occurring in the frontal and temporal lobes, the injury has also been found in the basal ganglia and cerebellum.
4. Extradural Hematomas - This injury involves a collection of blood outside the dura between the inter-table of the skull and the dura.

Note that even more damage to the patient can occur as a result of secondary damage due to the continuous process of the initial insult. Intracranial pressure caused by ongoing hematomas can be more damaging than the initial insult to the brain itself. Where cerebral blood flow is cut off, without relief, death results.

As contrasted with the devices/tests which analyze brain structure, discussed above, the following are utilized in order to quantify and measure brain function:

• Functional MRI (fMRI);
• Positron Emission Tomography (PET);
• Single Photon Emission Computed Tomography (SPECT)

Functional MRI is gaining wide use as a neuro imaging technique for measuring brain function. The test operates under the assumption that an increase in neuronal activity results in an increase in local blood flow leading to reduced concentrations of deoxy- hemoglobin, a product of oxygen consumption. This concept is widely known as blood-oxygen-level-dependent (BOLD). fMRI is particularly effective in moderate to severe TBI as studies of working memory on these patients suggest bloodflow abnormalities relative to comparison subjects, particularly in the frontal lobes.

Positron emission tomography uses very short-lived radioactive isotopes of elements commonly used in brain metabolism (glucose), and then shows an image which represents not only brain structure but also brain function (i.e., how the glucose is used). Positron emission tomography shows that language happens in a parallel array, and that the brain simultaneously processes in several areas at once as opposed to serially. In essence, PET is a diagnostic imaging technique for measuring regional brain metabolism. The clinical uses of PET scanning include brain injury evaluation; organic brain dysfunction; Parkinson´s disease; epilepsy lesion location in pre-surgical evaluation; cerebrovascular disease (stroke) and assessment of recovery; differential diagnosis of Alzheimer´s disease and other memory disorder; and differential diagnosis of brain tumor and radiation treatment. Even where there is no abnormality found on MRI or CT scan, PET scans have shown abnormality consistent with postconcussive syndrome and mild TBI. In most jurisdictions, however, the abnormality found on PET must be correlated with neuropsychological testing before it becomes admissible in court.

Single photon emission tomography is another generation of cerebral nuclear scans. It is commonly used for the study of circulation and perfusion of the brain. It is a computer-an enhanced version of a brain scan. It produces regional maps of the distribution of radioactively-labeled tracers in the brain with more resolution than traditional brain scans but without the cost of PET.

While not conclusive, these tests have provided validation for neuropsychological assessments and in the setting of the courtroom may provide the jurors with a picture of the invisible injury.