Somatic and Psychic Reactions to Industrial Noise

Communication by Alfred Tomatis published in the Archives des Maladies Professionnelles (Vol. 20, No. 5, 1959, pp. 611-624). The author, extending his earlier work on occupational deafness and objective audiometry, here broadens the debate to somatic and psychic reactions provoked by industrial noise. He distinguishes a first group of reactions whose starting point is auditory impairment (asthenia, irritability, psychic disorders, post-traumatic syndromes), and a second group whose manifestations are independent of the ear and arise from a direct mechanical action of noise upon the tissues, at high intensities (130-170 dB). The analysis leads to a vibratory physics of the “pathology of noise” from which the author draws the consequences for occupational medicine.

III. — Somatic and Psychic Reactions to Industrial Noise

By Mr A. TOMATIS (Paris)

Printed with the periodical Archives des Maladies Professionnelles. Extract from Vol. 20, No. 5, 1959, pp. 611-624.

Introduction

To be sure, it is of the ear and the ear alone that one thinks when it is a question of noise. Was it not particularly conceived to perceive it, to learn it, to taste it? Was it not specially designated to hear?

This strict application to the unique function of the ear, this restriction of a physiological order, seems all the more unknown in the study of the pathology of noise. The ear, it is known, considered whether another organ may be affected, even perturbed in its functioning where noise appears. Are we incapable of envisaging disorders otherwise than through the ear? But no, no more than we see otherwise than through the eye.

All otherwise said, today, reveals to us that noise perturbs the entire organism. How can it be then that they have been considered as the prerogative of the ear, and the ear having the privilege of hearing noise, it is not alone in receiving industrial noise.

To give back, it is true, is no longer noise properly speaking — that one may grasp, and that we conceive — but new fibres that escape the abnormal physiological woods of perception.

There has been raised, in truth, no exact designation to characterise it, to designate it. So it would have been more precise to speak only of industrial vibratory phenomena. This more physical terminology would have the advantage of grouping, indeed, all the vibratory manifestations that one observes in the different paths of this acoustic vibratory energy.

Noises are not in fact original; the audible harmonic noises, otherwise sounds, occupy their place in vibratory phenomena, while the monstrous hypertrophy of their parameters, notably of intensity, leads to industrial noise.

The ear has nothing of this “Physical agent”, sly and violent, called noise. First ravaged, first injured. It is broadly torn, saturated, rapidly written; and what our studies on it, thanks to the series of current examinations, reveal, is not its mode of behaviour in the evolution of its destruction more than its structure itself.

But will this destruction be without damage to the rest of the organism? Shall we not see appear a host of clinical and general signs translating the secondary impairment? Are there not, finally, somatic and psychic reactions independent of auditory impairment?

It is to respond to these various questions that sum up our current research that we shall adopt the following framework: Reactions of the ear. — Somatic and psychic reactions whose starting point proves to be secondary to auditory impairment. — Finally the reactions apparently independent of impairment of the ear.

Reactions of the ear to noise

They are comprised, in their evolution, in three classical phases. They lead ineluctably, sooner or later, in function of the time of exposure, in function of the quality of the noise, in function of the individual sensitivity of the exposed subject, to occupational deafness.

This rapidly irreversible variety, so difficult to compensate, soils audition without destroying it completely, by disaffecting the zone of interest by partial discrimination of the receptor, modifies the audiometric curve on an always identical profile, and is, all in all, so characterised by its narrowing of the auditory field.

The one whom it strikes is not a deaf person, but a special deaf person. He will hear, but understand nothing further.

Occupational deafness, broadly developed elsewhere, is only the culmination of the ear’s behaviour towards noise. Is this to say that the ear may, from then on, be practically unassailable? Does it allow, or simply without revealing any signs upon which it is taken, not to give itself otherwise than by a fall of the perception of its signs?

These are problems whose full importance may readily be measured. It is true that there exist auricular reactions translating the auditory suffering; and if it is possible for us to detect the moment when the ear risks reaching a stage beyond which lesions are irreparable, we shall then have acquired a considerable element in the fight against the harms of noise.

For some years, we have devoted ourselves to this problem — namely, how an initially normal audition could behave under noise before undergoing definitive and significant alterations. We have tried to evidence a characteristic alarm sign, indicating the opportune moment to intervene. We have tried to define the modalities of evolution.

First phase — Phase of awakening

Auditory sensitivity, widely developed by the intermediate absorption of the ear, is not at all normal. It is, in general, slightly excessive, accentuating the sensitivity of the exposed subject. Under a form of systematic examinations, a curious auditory recruitment appears. Yet it soon yields to the true persistence in the perception mode of the ear; the subjective perception is a little higher in the high frequencies than the average.

The side of effacement of the middle ear is then modified. It becomes incapable, apparently, of protecting the inner ear; and it is the latter which, through the circulation of sounds, is obliged to call upon protective muscles — that is, which is on the alert.

Cochlear protection is fully effected, it seems, by a tension sufficient to play a role of intensity reducer; the tension of the tympanic membrane in the neighbourhood of the base — that is, at the level of 4,000 Hz — increases in such proportions that partial destruction tears itself away, by tearing or micro-lesions of the membrane, reducing the osteo-muscular resistance of the transmission apparatus, which translates the leverage by a reduction of the air-bone frequency sounds, and is always observed. They prelude the lesion proper, and the inner ear, by an instability with prestige, by a crispation of the compensations in the first instance.

It is the goal that fights, it is the wind that saves, it is the high opening. Whatever then the frequency that the inner ear is attributing, it will yet be able to come out towards the exterior, that is, the mobile membrane, at the base.

The muscular base, in the long run, becomes worn so that the bits of this broken posed see the ear in their turn. Fatigue establishes itself, stabilises rapidly.

This phase lasts only a few days; audition returns to its earlier rate as soon as a fairly long stay suffices. It must be sought. It must be systematised. This demands much time. It is to be feared that if there existed a clinical research laboratory possessing both technical and medical equipment suitable, to lead a fruitful research on the mechanical evolution of sonotones devolved to the renovation of the renovation, the markings and the quality of the great deafness, the curves of different functions of the ear such as the curve is one.

Second phase — Phase of alarm

How long will this phase last? It is longer or shorter in function of the importance of the ambient noise, of the continuity, the duration of the rest phases, and the practice of recovery construct, in fact, in function of the factors liable to engender or move excessively upon an oléo-muscular organ.

In environments of the type of éclausante shocks, audition again the day after. It may make a deficit of the alarm phase. A discontinuous one not exceeding 110 dB in its global intensity, the alarm phase may last several weeks to a few months. By contrast, near piston aircraft engines or reactors, this alarm phase is considerably shortened and may last only a few days or a few hours.

This phase is truly the announcer of the imminent deficit of audition. It appears from significant establishments of the physiopathology of the ear. It is translated, as we have said, by somewhat particular subjective manifestations, such as tinnitus at constant high frequency, vertigo, sensation of collapse of the accommodation potential of audition on the frequencies of the air and of the malleus.

There must only be seen here an excessive permeable fatigue such as one might admit from the two extreme modes of too-frequent repetition of one and the same movement, or of the reverberation of a tension of too long duration — for the gesture of repetition in the occurrence will not have this concession. So we must expect, in parallel, more and more considerable, an appreciable change in the quality of audition during the following phase. The confirmation of this hypothesis is given to us by the recovery of audition upon the placing at rest of the subject for several days in relative silence.

One readily conceives that an alone, with the lightness and insufficiently sustained demands of its transmission, amplification, reduction, compensation apparatus, may entail too much, reverberate painfully. One understands that the noise demands rather metallic, immortal edging. This is a phenomenon of painful hyperacusis identical to that gathered in the course of facial paralyses.

In other words, the subject reaches this stage where the defence shocks of his apparatus exist, the lack of auditory tension would require it of the mobile membrane, similar null little until it no longer nuances to most a muscular intervention — through which it is not even of a mechanical transmission.

Third phase — Phase of exhaustion

While the ambient noise continues its destructive effects upon the ear, perception — as has been seen — modifies itself, transforms itself in its quality; the auditory field alters by destruction of a broad band of high frequencies. There remains only a kind of low-pass. Noises become more matted, the high frequencies and notably the harmonics disappear; the alteration affects the timbre, the brilliant quality of all sensory auditory excitation dulls. Dirty, dull, muffled, dry, white sounds, without relief, without flavour, wearying, exasperating, suffocating. The incomprehension of all conversation appears. The subject becomes an indigestible magma of noises and confusions useless, puerile, inculcable — the whole leading to the perception of a succession of a thousand sounds of palpable medium brilliance, but faded.

To hear is to understand. It is to this monstrous infirmity that occupational deafness leads.

There is hardly a torment more singularly disheartening than this permanence of the ear to speak. The subject does not hear; for most of the syllables, they are only a sown mixture of new phenomena.

But this is not all yet. The ear, totally suffering much mute and obfornitur, then has even greater inflorencies whose analytical development would be always always limited. In occupational deafness, it is known. The more conversation unfolds, the more audition will be fixed, the more dissertation will be cut. There is no longer any unrestrained grain.

The punime, one suspects, will faithfully follow the auditory scheme. It will be all the more affected as the disintegration progresses — the negative translation of a more significant auditory clogging. Moreover, as this aeration affirms itself, the more disconcerting, decroting, charging again, joined to the ear, many other aggressions more or less significant. The fear is then that the existence of a radial pathway, without the noise of chuintating, chitinous, brilliant, exalting noises. We need, the ear needs to be permeated with harmonic sounds. The phenomenon seems to us capital. It is possible for us to live in dull environments, not that we are means of attention as to maintain it, but it will be diminished by a parcel of air-tutor, that we can manifest the expression that to live is principally clear; conversely the tableau sounds insult the rain.

Education of the ear to noise

It is a true gymnastics of the ear, which pertains to a physical culture imposing very precise, well-appropriated movements.

The aim to attain is, let us specify it anew: to bring the muscle of the stapes to its maximum, to relax the tympanic membrane to its maximum.

To place the muscle of the stapes in easy chain. It suffices to progressively increase the step of acoustic pressures — that is, to open the muscle to ever more important tension thanks to “polets”, acoustic exercises under which one chooses the sonic vibrations. It is simple. To do this, it will suffice to have an ear hear noises of increasing intensities.

To obtain a maximum relaxation of the tympanic membrane is a more complex realisation. One must impose upon the muscle of the malleus a maximal elongation — that is, to bring an extreme position to the inco-malleolar block by attraction of the muscle of the malleus as far outward as possible. As we know, as we have seen, this exaggerated displacement entails a recoil of the stapes, relaxes the whole.

How to achieve this? Physiologically and practically it is the effort furnished to listen to lower sounds heard at a voice of low frequencies which is imposed. To their stapes, the tree the queen, to listen to ten-thousand sounds. The notches are arranged. The tucking-in is itself, long and monotonous. The muscular movement will well cover yet to the frequencies to be heard in the zone of medium lows — that is, to the components at d-of 500 periods — one must exist a maximum relaxation at the level of the tympanic membrane.

We see moreover, in the course of treatment, in the laboratory proving education from manufactured noise, considerably its estimation of its adaptation to the perception of low frequencies. In other words, the perception of the low is shaken and is made, under Lockian adaptation, a true prefiguration, a true mobilisation of the membranous apparatus to attain directed spatial positions.

Somatic and psychic reactions whose starting point proves to be auditory impairment

We shall intentionally group the somatic and psychic reactions that we shall encounter in the presence of a factory noise whose still-measurable aims, for the ear, are without damage.

We shall observe the conditions: the ear sees its auditory field considerably modified in its structure, without damage to the whole organism.

The extraordinary sensitivity, without equal, the excessive susceptibility of the auditory apparatus, explains with what importance, with what acuity, the signs of audition will arise from this painful intoxication that is noise. Loud manifestation is found considerably acute by a neurovegetative dystonia whose ground is yet all of borborygmi, and the whistlings of the ear are the first local signs whose aetiology is directly attached to the valentinois agent. Headaches, going as far as being accompanied by chronicles, translate the exarchaltation of a stimulating pendulum excitation, to a foamy palette.

It is the fact that comes at the head of the most frequently encountered disorders, asthenia which justifies itself there. Everything seems normal. The clinic remains mute, appetite is preserved, sleep deep. The examination does not plead in favour of an intoxication by noise. Soon, however, weariness is accompanied by an often appreciable, considerable weight loss, always quite surprising given the apparent good physical form, in its aetiology. Even for itself, the subject has, indeed, his tonus, his desire to do; and the rituals of noise, of tendencies. He becomes secondary in excitation, his humours are changing, he manifests his character. The modification of Hendrey’s angle inscribes itself progressively and clearly as a characteristic dimensioning for the harmful agent.

Only a notice teaches the deficiency of the inquiry sets itself faithfully to work, no aetiological diagnosis to seek, that the employee evidently — a malparcellary without valid explanation.

Moreover, the weight loss may reach a vertiginous figure, of the order of several kilograms per month.

The only veritably aetiological hitherto is the tiring syndrome — a syndrome which on the rapid rapidity disappears every day, and the recovery of depressions in case of placing at rest, often of duration not over a week, with the exception of nourishment that we know. The subject does not resume; in the course of work in a noisy environment, as experience proves, the syndrome resumes in an identical fashion.

Somatic and psychic reactions independent of auditory impairment

Do they exist? Are they conceivable? Can one envisage another entry door than the ear? It must not be doubted.

The ear was conceived, as has been seen, for our ear, noise — I have not turned it into auditory sensation, but into noise. The ear in particular is well made but does not perceive. But largely exceeded in that by industrial noise.

Graquereux and Grosson have, on many occasions, broadly insisted on the general syndrome due to noise. Husson grouped the clinical reactions under the name of trauma-sonic syndrome.

It is in the laboratory that Grosjean has brought us the most striking proofs of the harms of acoustic vibrations, whose intensive noises considerably exceed the auditory frame. It suffices to recall the research on the animal placed in the presence of an ultrasonic siren: the hamster at 160-170 decibels.

At present, the authors arrive at almost identical conclusions on the non-noise intensities (130-190 dB) — that is, not in their mode of action certainly, but as to the incompatibility of life in their presence.

The disorders obtained in the course of artificial experiments emerge, gathered with probably equivalent alterations to those noted following conducted clinical intensities.

To understand better how a vibratory phenomenon may be dangerous, to grasp better its harmful effect, its nature pain, to determine better its mode of penetration into the organism, sounds of analysing it, of dissociating it, by drawing out certain of its different parameters.

What is noise? — Such is therefore the whole problem. Upon the solution depend the coordination of clinical signs grouped a little too symptomatically confusedly, and we shall re-establish an appropriate therapy, liable to make some elementations.

To be sure, it is a physiology apart. We shall try to penetrate the intimate structure of noise, for it is again there that the pathogenic agent is.

It is known that the sound wave results from any disturbance whatsoever of the air, from near to near at a fixed speed for each milieu, and propagates itself. This propagation is very complex and not a simple transmission of departure impulse in simplified terms. It is a true chainening from near to near, molecular oscillations of the element around its position of equilibrium, in modifications that do not import the element, but a point of variation, which propagates by neighbourhood — like the bright the leap on its arrests the constraints allions on the water, which by vibratory movements arrive at an ensemble of a thousand molecules, are actuated, are coordinated, until considerable — not of autonomy a unit of life to study the nuance.

However, to examine it, this module to communicate its movement of transmission, of vivacity, its explanation may introduce the event and the insula. They would know to the air, in heat naturally, this deduces declaration outside notion notably: the phenomenon is devastating or bréguette.

How then are these ensembles, which seen in air in foam in our notes, all the more so as the motif is an undeniable mediation of fitness sounds?

Of the pathology of noise

From these examples one may multiply and draw the notions of the acoustic wave and the mechanical wave.

The acoustic wave is nothing but the expression of the transmission of sound; its realisation engenders itself only in the seeing, that the molecule, under the impulse of an external force, has by wheel its position of equilibrium momentarily and faithfully transmits this vibratory perturbation to its neighbourhoods.

But until it is a question of a vibratory movement, giving, around the point of equilibrium, more than it is a question of a being éroé between distinct cases, there is doubtless the appearance of a “resonance”. This latter, in any case, is akin during vibratory movements which respond to the best, most altered conditions, these particular dispositions inherent in the agent’s subject. It from agent a veritable replacement from near to near of a loss of water until its own, but in the décor of their pre-existence. We shall call this resonance of the counter-reactions molecular resonance.

It is the molecular resonance, at 161 Hz of agréeufer to transmit from near to near. We shall call molecular resonance, from near to near, even molecular conferences specific to the milieu.

It is to it that would have remarked the fact, that just as the leaf of a sidewalk girl, scolds itself a hand, in the practice of fibres for the establishment of the chamber permits would become a solo of the object which preauguait the frédances acquired. Thus, the siren, one is perfectly recognised that it was a piece of sheet metal; the same things one has recognised the proper timbre. And it is the same of iron, copper, air, wood, etc.

This molecular resonance is therefore sufficient to create a in its vibration, to propagate it, but it is thus necessary as that of made between another acoustic vibration; that is to say what the transports of molecular resonance are its own frequency.

This is why, whatever the emitted frequency, imposed upon a body in itself, it will immediately radiate the sonority specific to this body. Thus, if a violin voice is another organic acoustic, not only of the frequency emitted by the violin, but of the molecular resonance of the latter. It is the fact of simple bodies characteristic such as glass and crystal.

To suppress this phenomenon is to suppress the vector, the support of the acoustic vibratory wave — it is to stifle the noise.

The mechanical wave, in the sense of the specific resonating vector, which would not know in the caisson a fluid milieu for a solid milieu which is freed from a molecule at the frequency of the emitted sound. This latter will be, certainly, a function of the milieu, but also of its experience.

The music wave is nothing other than the vibratory phenomenon such as the potential never has it, which is to our scale. Its propagation, its absorption, its reflection, its refraction are so many factors which will interfere with penetration into the natural milieu. This latter will be, certainly, a function of the milieu, but also of its resonance.

Conclusion

It is an immense subject we have just broached. It was indeed a matter of grouping, in its ensemble, a sum of work whose extent. However, it had to be envisaged. We have tried with the minimum of means — must we apologise? — to show all the importance that the pathology of noise assumes and to what point it is pressing to be alarmed about it, how urgent it is to defend oneself from it.

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Source: Tomatis A., “Les réactions somatiques et psychiques au bruit industriel”, Archives des Maladies Professionnelles, Vol. 20, No. 5, 1959, pp. 611-624. Offprint printed in France by Mame, Tours (Imp. 503/1959). Legal deposit: 4^th quarter 1959, serial no. 3,475, Masson et C^ie, publishers, Paris. Digitised document from Alfred Tomatis’s personal archives.

Editor’s note: the transcription faithfully follows the original text as it appears in the offprint. Several technical passages bear the traces of printing errors and abbreviations proper to the occupational medicine of the time, here preserved as such. The digitisation, effected from the archive document, contains in places uncertainties of optical recognition which may affect the detailed reading of certain paragraphs.