Morton Nathanson

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.