Philip S. Bergman

Significance of Oculocephalic and Caloric Responses in the Unconscious Patient

at times that these signs do not reflect the true degree of unconsciousness. The literature makes little reference to the oculocephalic reflex (“doll phenomenon”) and the caloric test in relation to the state of consciousness or as a means of localizing lesions in comatose patients. The value of vestibular stimulation, particularly the caloric test, as a localizing tool in intracranial disorders has been reported extensively,la but no reference could be found which described the influence of the state of consciousness at the time of testin . Ford and

Electrooculographic investigation of the caloric response.

IN SPITE OF intensive study, the normal parameters of the caloric response have not yet been clearly delineated and there is little general agreement as to what constitutes an abnormal caloric test. A profusion of differing technics for performing the test and a widely varied emphasis on different aspects of the caloric response have further obscured the problem. The present investigation was carried out in order to [l] study the recording characteristics of the caloric response in the normal subject under various conditions and [2] make an objective comparison of the normal response with the patterns observed in patients with intracranial disease of various types. The 3 fundamental aspects of the caloric response may be summarized as follows: Nystagmus with a quick and slow component appears after the introduction of a thermic stimulus into the external auditory canal. If the stimulus is cold, the quick component will be in a direction opposite to the side of stimulation; if warm, the quick component will be toward the stimulated side. Typically, the quality of the nystagmus varies with changes in head position. Some manifestation of postural deviation, in association with the nystagmus, is usually present in the normal subject. Past pointing, inclination of the head or body, and falling toward the side of stimulation (with cold calories) or away from the side of stimulation (with warm calorics) are the usual examples. Systemic response, with vertigo, nausea, vomiting, and diaphoresis often occurs. Oscillopsia may be reported by the subject. At the present time, electrooculography offers the best means available for objectively studying the ocular reaction to caloric stimulation. With this method, many of the factors that iduence the oculomotor response may be analyzed. The effects of eye closure, darkness, fixation, gaze position, and head position are easily ascertained. Analysis of the duration, direction, frequency, and relative amplitude of the nystagmus is facilitated. In addition, the ease of recording and the attainment of an objective and permanent record for purposes of comparison are distinct advantages.

Effect of intravenous barbiturates on abnormal involuntary movements.

ABNORMAL involuntary movements are classified for the most part symptomatically that is, by the type of dyskinesia. However, not all involuntary movements which appear similar have the same characteristics under different conditions of investigation. For instance, during sleep some dyskinesias disappear while others persist. Another means of comparing these phenomena is by their response to drugs. The present study concerns the effect of an intravenous barbiturate, sodium Amytal (amobarbital sodium). This drug was used because it has rapid, predictable and easily identifiable effects upon the functions of the central nervous system.

Electroencephalographic and convulsive responses of patients with brain disease to methetharimide

METHETHARIMIDE ( p, p-methylethylglutarimide), known also as Mikedimide, Megimide, bemegride, and Parlam, has been used as a barbiturate antagonist since 1954.l-O It has also been used in electroencephalographic activationB-11 and is essentially similar in its action to pentylenetetrazol (Metrazol) , producing paroxysmal bursts of spikes and slowing7-11 and grand ma1 convulsions.~J9~1* It may be more valuable for this purpose than pentylenetetrazol because the electroencephalographic changes and seizures are induced more gradually and the procedure is easier to control and observe.7-8JOJ1 Activation studies using pentylenetetrazol have generally been concerned with the study of epilepsy and directed mainly at electroencephalographic changes.13J9 The work of Ajmone-Marsan and Ralston13 with a group of patients with chronic epilepsy being evaluated for surgery emphasized that observation of the induced seizure can give data of value in locating an epileptic focus. The present study was begun to investigate the electroencephalographic and convulsant effects of methetharimide in patients with brain disease with or without epilepsy. Particular attention was given to the effects of the drug in patients with unilateral brain disease. If unilateral disease were to be reflected by an activated electroencephalogram or in focal convulsive phenomena, activation with a convulsant agent might be a valuable tool in the localization of brain disease. This has not been directly investigated in man. Several studies have reported that nonepileptic lesions can cause ipsilateral electroencephalographic

The significance of focal electroencephalographic abnormalities in the "wrong" location.

OCCASIONALLY an electroencephalogram shows focal abnormalities on one side of the brain when the clinical picture points to the opposite side. Fortunately such records are rare, probably even more rare than those that apparently fit the neurologic symptoms and then, unknown to the electroencephalographer, turn out to be inconsistent with the final diagnosis. This latter group, however, is not considered in the present study. The literature’-8 does not deal with this problem to any great extent. The clinical findings are rarely emphasized in reports of localization studies, as the electroencephalogram has been considered predominantly in respect to verified pathology. Such studies usually relate the electrical abnormalities to the surgical or autopsy findings, and the material consists largely of mass lesions. The usual implication is that the neurologic findings corresponded to the anatomic site of the lesion. Strauss, Ostow, and Greensteinl state that they did not encounter a single tumor which gave an incorrect EEG lateralization, at least up to the time of their publication in 1952. Courville’s large series2 contains only selected examples with clinical details. One case which he described was a subdural hematoma on one side, but the electroencephalogram and neurologic signs both pointed to the opposite cerebral hemisphere. He also reported an amustic neuroma, diagnosed clinically and verified at operation, which showed a slowwave focus in the opposite frontotemporal region. Cobbs studied the recordings in 104 supratentorial tumors, 2 of which showed foci on the wrong side. He, however, gave no clinical details and at that time was using an electroencephalogram with only 2 channels. Rodin and others,’ using alpha suppression and delta foci as localizing signs, made 3 lateralization errors in 28 tumor cases. In 2 of these, delta foci were misleading. Again, he gave no correlation with the neurologic status. Marsh and others6 gave the findings in 9 unilateral subdural hematomas, in 2 of which a focus of suppression was misleading. They did not state whether the neurologic hdings also pointed to the wrong side. Yeager and Luses reported wrong-sided delta foci in 2 of 100 “cortical tumors.” Dow and Grewe’ reported that 3 out of 9 cerebellar tumors showed occipital slow wave foci. They also noted that in 100 tumors of the cerebral hemispheres, only 2 had focal changes on the wrong side. In the first of these cerebral tumor cases, there were no localizing neurologic signs in a patient who was semicomatose. This EEG was diffusely abnormal, with a slight accentuation in the left frontal area. The tumor was found to be in the right frontal area at operation; no follow-up was given. Their second patient had a left hemiparesis and left hemisensory changes on double simultaneous stimulation. Diffuse slowing was present in the EEG, mostly frontal and more on the left, but the operation disclosed a right frontal glioma instead. The patient was still living at the time of the report so that no further verification was obtained. These investigators maintained that coma was the most im-