PSYCHO-PHYSICAL INVESTIGATIONS WITH THE GALVANOMETER AND PNEUMOGRAPH IN NORMAL AND INSANE INDIVIDUALS
CHAPTER 3: THE PNEUMOGRAPH AS AN INDICATOR OF PSYCHIC PROCESSES.
The relation of the respiratory innervation curve to psychic processes in both normal and pathological conditions has not yet been thoroughly investigated. Mosso (1879-1893) was one of the earlier investigators in the physiological application of the pneumograph and could reach no satisfactory conclusions from a study of the respiratory curve under sensory stimulation. Delabarre  states that respiration increases in frequency and depth with attention. to sensory stimulation, and with
FIG. 6. H., an attendant, normal curves, very labile emotions. The numbers here correspond to the series of mixed stimuli, 15 is threat of weight.
mental processes increases in frequency and diminishes in depth. Lehmann  states that every pleasant impression increases the depth of breathing, and that strong unpleasant impressions are accompanied by several deep respiratory movements. Mentz  employed pleasant and unpleasant acoustic stimuli in a study of the pulse and breathing, and as regards respiration observed with strong stimulation first slowing and then shortening of the respiratory movements. He noted also a marked influence of attention on the results. Involuntary attention generally induced prolongation of breathing, while voluntary attention caused abbreviation of the movements. Pursuing his studies farther he investigated the action of pleasant and unpleasant stimuli and of the effects upon pulse and respiration. As regards the former, pleasant feelings lengthened the pulse curve and unpleasant ones shortened it, and he regards the respiratory curve as running a parallel course. With affects there was prolongation of the respiratory movements, and with increasing strength of the affects an increasing height or depth of the breathing curve. Zoneff and Meumann  finding nothing sufficiently definite in literature in relation to the correspondence between respiration and circulation and psychic or emotional processes, have made an exhaustive research upon normal individuals, employing various stimuli, optic, acoustic, gustatory, cutaneous and psychic (arithmetical problems and space conceptions) and studied at the same time the effects of voluntary attention and pleasant and unpleasant impressions upon the breathing and pulse. They found that as a rule attention produced acceleration of the breathing, especially at the end of the stimulation, and in addition to acceleration the breathing might become more shallow or be inhibited. This inhibition may appear as shallow and more rapid breathing, or there may be a partial or complete standstill of the respiration, and is greater in direct proportion to the degree of attention. Complete inhibition was found more often in attention to sensory than to intellectual stimulation. There were variations in the results in different individualities. There were fluctuations in the curves which they considered as being due to fluctuations in attention. In relation to pleasant and unpleasant stimuli they concluded that all pleasant sensations cause shallowing and acceleration of the breathing, and all unpleasant sensations deepening and slowing of respiration, or, in other words, that the former diminish and the latter increase respiratory function. In experiments with diversion of the attention together with stimulation, they found that emotional effects upon breathing and pulse ceased. In experiments with concentration of attention on stimulus and sensation, attention strengthened the effects of both pleasant and unpleasant feelings upon the curves. While their work is the best that has yet appeared upon this subject, it must still be confessed that experiments of' this nature carried out upon the trained assistants or students connected with the laboratory are more or less artificial, and this, together with the extremely simple character of the stimulation, would make their criteria for complex emotional phenomena with which we have to deal only relatively valuable.
Martius and Minnemann  in a thoroughly iconoclastic and yet excellent work point out many fallacies in the studies of Lehmann, Menz and Zoneff and artefacts of a mechanical nature, and wrong conclusions as to the relations between affects, and pulse and curves. They themselves find the normal respiratory curve inconstant, subject to variations due to age, temperament, perseveration of affect, reactions from the affect, embarrassment from the experiment, undue interest in procedures, &c., and their chief conclusion is that the main changes in breathing in emotional conditions consist of quickened or lengthened tempo, with diminished in either case.
Believing that a study of the inspiratory curve would throw the most light upon the relation of respiratory innervation to psychic processes, we set before ourselves problems for consideration, viz., the character of the usual respiratory curve, the character of the curve in stimulation without verbal reaction, the influence of verbal reaction with indifferent stimuli upon the curve, whether distinct emotional complexes affected uniformly the pneumographic curve, whether there were marked disturbances of the respiratory without corresponding changes in the galvanometric curve, and, finally, what influence attention has on both galvanometer and pneumograph. We have not been able as yet to reach satisfactory conclusions on all of these points, for the material already available is more than we have yet had opportunity thoroughly to investigate; but so far as the results obtained are of interest. The figures in the table given below show a regular, though not constant, relation between the galvanometric and the pneumographic curves in one case.
Measurements to Show the Relation in Frequency and Amplitude of Inspirations to Ascending and Descending Portions of the Galvanometer Wave
To obtain these relations it is necessary to select an experiment in which the galvanometric curve has not been influenced greatly by the several sources of error, and the simultaneous pneumographic curve has not been modified too much by verbal reaction, coughing, &c. Taking the typical curves of several such series, measurements were made to determine the relative number of inspirations synchronous with the ascending galvanometer curve, and also with the descending galvanometer curve. The amplitude of each inspiration was also measured and averaged for the same purpose, and the measurements are recorded in millimetres. It will be seen that the ascending portion of the galvanometer curve, which is the result of an emotional stimulus, is accompanied by fewer inspirations as well as by deeper ones. While this seemed to be a general rule in this instance, we find variations in different individuals with the same mixed series of stimuli, and in some cases the reverse. The stimuli in the table were unpleasant rather than pleasant to the test person. But the determination of the emotional tone in any such experiment is very difficult. The forced and artificial situation of the test person in itself induces pleasant feelings, and any pleasant stimulus must therefore simply bring about a certain relief or relaxation in a situation of unpleasant tension. The nervous tension during an experiment must naturally influence the breathing, and a pleasant stimulus is apt to produce only a temporary lessening of such tension. This is a criticism we would make of the Zoneff and Meumann experiments, and of experiments with the pneumograph in general. It is altogether probable that there are more inexplicable influences at work in relation to the pneumographic curve than we are at present able to comprehend. There are many respiratory fluctuations which have nothing to do with the emotions, but are the result of physical or intellectual processes, with the enforced quiet of body of the test person, with the disposition to speak, with tendencies to cough or to swallow, &c. Furthermore, there will be a difference in the curve if the stimulus occurs during an inspiration or an expiration, and there are individual variations dependent upon temperament, upon lability of the emotions.
We have, therefore, not been greatly impressed with the value of a possible relation between the galvanometric and pneumographic curves since it is not constant, and the more we have studied comparatively the two synchronous curves, the more have we been impressed with a surprising divergence between the influences at work upon them. We have studied hundreds of waves in every conceivable manner. For instance, we have taken series of galvanometric curves and carefully measured the length of each inspiration, and the intervals between inspirations, as related to the point of stimulus, to the latent space before the ascent of the galvanometer wave, to the ascending curve, to the crest, to the descending curve, and to the space to the next point of stimulus, without developing any regular and constant relationship or correspondence, though we think this may ultimately be shown to exist in some degree. On the contrary, we have found thus far that the influences at work upon the two curves reveal an astonishing regularity of difference. When the emotions are very labile, and show the most marked excursions in the galvanometer curve, the respiratory curve is often regular and even (fig. 7).
Fig. 7. Dr. P., normal good-sized galvanometer curves with fairly regular respiratory curve.
On the other hand, in instances both normal and pathological, where the galvanometer curve is marked by little fluctuation, or even by none, as in some cases of katatonia, there will often be most decided variations in the pneumographic curve. We often note a change in character in pneumographic curves, not so much with each separate stimulus, but during the whole course of a series of stimuli as if expectant attention and nervous tension diminished the inspirations during the early part of the series, and as if there were a relaxation during the latter half with longer inspirations (fig. 8).
FIG.8. Dr. S., a patient with paranoid dementia (Case No. 8). Extraordinary emotions expressed in galvanometer curve. Considerable tension in pneumographic curve from stimulus 2 (fall of weight) on, with relaxation and deeper breathing beyond stimulus 7. An example of perseveration of tension for a long period in the pneumographic curve.
There does not seem to be the intimate and deep relationship between the respiratory function and the unconscious emotions that exists between the sweat glandular system and these emotions. It is a matter of everyday experience that the respiration is influenced by our conscious emotions, especially when they are strong, as instanced in such expressions as “baited breath," "breathless with astonishment," &c. Such inhibitions of breathing are noticeable in many pneumographic curves, particularly in association with expectation and tension. But do, perhaps, the emotions of the subconscious, roused up by questions or words that strike into buried complexes of the soul, reveal themselves in the galvanometer curve, while the pneumographic curve is comparatively unaffected? Respiration is an instrument of consciousness. You can control it voluntarily while you cannot control the galvanometer curve. The respiratory innervation is closely associated with speech innervation, anatomically and functionally, and the physical connection in the brain is, perhaps, one of the closest and earliest. Let us take these remarkable curves of a case of acute katatonia (figs. 9A and 9B), which may be regarded as a psychological experiment in diverting both attention and ordinary emotion.
FIG. 9. J., acute katatonic stupor (Case No. 10). A is a wave selected from the series in which 6 is sudden call by name. The galvanometer curve is slight, but the change in the pneumographic curve is notable. B is the same stimulus in the repetition of the series.4
Attention and all other emotions being practically diverted the pathological process, the galvanometer curve is slight (indeed, in the second repetition it was a straight line), but the sudden call of the patient by name produced the extraordinary fluctuations in the respiratory curve, though nothing was apparent in his outward demeanor to show that he was conscious in any degree of the stimulus. He may have been conscious of the call, but we had no means of determining this. In the repetition the same fluctuations occurred, proving that they were not fortuitous. The only reasonable explanation of this phenomenon, in our opinion, is that the call of the name developed a disposition to speak, stimulated the hearing centre, and the closely-associated speech centre, the motor innervation from which acted upon the respiratory muscles. Ordinarily a sudden call by name, which is one of strongest and deepest of stimuli, produces an answer. In this instance the call by name was a stimulus that acted as in a simple reflex process, and led to motor manifestations in the respiratory muscles connected with the motors speech centre, analogous to the contraction of the eyelids in response to a sudden flash of light. Fig. 10 is another instance of almost like character.
FIG. 10. Miss S., paranoid dementia (Case No.2), stimuli 9, 10, 11, 12, correspond to numbers in the mixed series printed in the text. The noteworthy changes in the respiratory curve are due to her constant “disposition to speak.” She did not speak except in answer to the questions given, but she apparently whispered most of the time between audible answers. Sometimes there was slight movement of the lips, when real whispering was not apparent.
While inconstancy of emotional variations in the respiratory curve and in correspondence with the galvanometer curve has been the rule in our findings thus far, we have learned that inhibitions, when they occur as an expression of expectant attention or of other emotions, are almost always shown in the expiratory curve and not in the inspiratory, which would accord with our idea that intellectual, emotional or conscious innervation is associated with inspiration, whereas expiration is rather a physical process or relaxation, prone to be inhibited, but not otherwise affected by the active respiratory nerves.
In reiterating our opinion that the galvanometer curve is probably more intimately connected than the pneumographic curve with the subconscious emotional complexes, we would add that there is a greater tendency also to persistence the pneumographic curve when emotion is expressed in it, for the galvanometer curve subsides rather quickly with the fall of the emotion, while the pneumographic curve may show traces of conscious reminiscence of the emotional stimulus for a much longer time. The galvanometer is rather an index or measurer of acute feeling tone.
Thus far, for the purposes of this study of the curves under normal conditions, we had made some forty series of curves in eight normal individuals, educated and uneducated. After this we made some thirty series of curves in eleven cases of dementia præcox of different types, viz.: Dementia paranoides three, hebephrenia two, and katatonia six cases (three chronic and three acute), and to these tests we will now turn our attention.
4. Fig. 9 reproduces the actual size of the tracing.