Baker report, 1968 congressional hearings

Once the examining physician has satisfied himself as to the status of an observer's visual apparatus (to the point where the
cerebral cortex takes over), he will want next to proceed with a detailed neurologic examination. His index of suspicion
about the presence of absence of pertinent central nervous system disease had already been altered by his findings on
general physical evaluation, as well as from the eye examination.
There is a clinical format for doing a complete neurologic examination; it is well-known to neurologists and
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other interested physicians. Certain of the maneuvers, particularly those which test cortical integrative function, are
extremely important in the evaluation of an eye-witness. This is because they will indicate the ability of the observer's
cerebral cortex to process what his visual apparatus has fed in -- to differentiate various kinds of sensory input, process
detail, make associations, and integrate spatial relationships. More specifically, those tests that reflect cortical sensory
status are particularly pertinent for eyewitness assessment. This is because there are numerous medical disorders that cause
neurologic disruption at the cortical sensory level, resulting in hallucinations, delusions, distortions, and confabulations [6].
"Organic" hallucinations and distortions often seem very real, even afterwards, to one only transiently afflicted and are apt
to be reported as witnessed events. They can occur in people suffering from acute infections, adrenal insufficiency, brain
tumors, chronic pulmonary disorders (respirator acidosis), complications from vitamin deficiencies and alcoholism,
abnormal calcium metabolism, low blood magnesium levels, epilepsy (for several reasons), and Sydenham's chorea. In
addition, there are scores of commonly used drugs which will produce hallucinations if taken in toxic quantities or, by
certain people, in prescribed amounts. These include antihistamines, meprobamate ("Milltown"), dephenylhydantoins
(antiepileptic agents), atropine (found in many non-prescription sleeping pills), and bromides (as in Bromoselzer). The
report of an eye-witness who has been scrutinized for these possibilities alone (by history, examination, and necessary
laboratory data) will understandably assume more creditability.
The possibility that an observation may have been influenced by an "organic" delusion should also be investigated.
Frequently, as with the hallucinations, there will be clues to this situation from the observer's history or from some
examination findings. Among the underlying medical causes of delusions are trichinosis, syphilis, hypothyroidism, calcium
disorders, various blood disorders, encephalitis, and pellagra. Some of these same disorders can, of course, also influence
observational reporting through other channels.
Confabulation, as a neurologic sign, is particularly important to rule out in the eye-witness report because it can be so
deceiving. In fact, it serves as a cover-up for memory impairment by filling in the gaps with sundry (but inaccurate) details.
Typically, confabulation is seen in association with peripheral neuropathy (careful examination is thus apt to alert the
physician) and is the result of either a blood) disorder or, more commonly, exposure to toxins [7].
Many gross mental aberrations, such as hallucinations and delusions, are not associated with abnormal physical or
neurologic signs and can be causally traced to underlying psychologic disorders. These are likely to be recognized and so
labeled in the neurologic phase of the assessment where, as in psychiatry, a standard mental status examination is used for
ferreting out emotional disorders, as well as memory and other intellectual impairment. For example, the schizophrenias
and psychotic depression (which are the more frequent functional disorders associated with hallucinations and delusions)
usually have well known clinical characteristics and will be obvious to physicians doing formal mental status testing [8].
It is because of the less florid kinds of psychopathology that a thorough psychiatric evaluation should be part of an
observer creditability assessment. The complexities and vagaries of the human personality can lead to some gross
distortions and fabrications around an event, particularly when finessed by people who are borderline psychotic, paranoid,
sociopathic, hysterical or inadequate personalities. Some of these people, when stressed, have brief, episodic breaks with
reality in which they are frankly psychotic and hallucinate, yet then resume previous functioning.
During a sophisticated psychiatric evaluation, the physician would be likely to recognize a propensity for such episodes.
His main job, however, would be to gather enough information about the observer as a person to be able to check him out
generally, psychologically, for creditability. This would involve complete developmental and psychosexual history,
studying family relationships (past and present), assessing intellectual ability, elaborating on areas of major conflict,
assessing for characterologic make-up and evaluating for ego-strength or weakness.