Stammering

Offprint. Article by Dr Alfred A. Tomatis*, then deputy director of a research laboratory affiliated to the CNRS, published in* June 1955*.*

Stammering — Essays on the Investigation of its Pathogenesis. Founding article, prior to the development of the Electronic Ear, in which Tomatis already establishes the notion of the directing ear and the role of the cochleo-phonatory circuit in the genesis of stammering.

Preamble

“Might there not be an auditory anomaly capable of explaining stammering?” — such was the problem set us by our master, Dr Tarneau, on the morrow of a demonstration given to us by Dr Dupoirieux on the delayed feedback test, evidencing the importance of the audition-phonation circuit.

This problem, deeply interesting, immediately demanded the possibility of examining a significant series of subjects afflicted with stammering. It is, still under the benevolent protection of Dr Tarneau, that we were able to gain access to the consultation of the Rehabilitation Service of the Hôpital Saint-Michel, where our task was facilitated by Miss Dinville, who directs the service.

The conclusions which follow bear at present on a first group of fifty stammerers, thirty of whom belong to Miss Dinville’s service.

I. General notions on stammering

Stammering is universally admitted as a disorder of speech due to a more or less marked nervous state — a neurosis of speech which most often appears in childhood, from the earliest years.

This disorder, extremely painful for the stammerer, entails a particular conduct in which are manifested the anxiety of speaking and the fear of the ridicule it provokes. One readily conceives the importance of this neurosis upon the social behaviour of the stammerer, who will be very closely bound to its permanent reverberation upon his psyche.

Statistics

Frequency: stammering is encountered in all parts of the world, but with a more marked frequency in cultured nations. In Prague, Seeman notes 0.80% of stammerers at preschool age; in Vienna, Czell reports the figure of 0.68%. For stammering children at school age, the figures are 1.1% for London and 1.52% for New York.

Age: it is between 3 and 5 years that stammering appears with the maximum of frequency, and in the proportion of 40% according to Seeman. It is therefore, as may be seen, principally at preschool age that this disorder is discovered. The distribution thereafter is roughly decreasing, from the beginning of school age to puberty.

Sex: all the statistics — and they are very numerous — reveal very clearly the predominance of the male sex. For Hulders, Van der Meer, Westergaard, Van Lierde and Reids, a ratio of 80 boys to 20 girls must be considered. For Froeschels, 66/33; for Sittig, 74/26; for Kadoleczy, 77/23. Whether this ratio is 3/1 or 8/1, the male sex always prevails. The explanation of the predisposition to stammering of the male sex has remained obscure to this day.

II. Aetiology: a survey of theories

The aetiology of stammering, in the present state of our knowledge, remains extremely uncertain, and the attempts at explanation made to our day still remain in the domain of hypotheses. All these theories — whether they emanate from physicians or from psychologists — aim to explain the origin of the neurosis of stammering. As Seeman justly remarks: their multiplicity is the best proof of their lacunae.

Here are the most important theories, as classified by Trösler:

1. Purely somatic causes: endocrine disorders (Slave, Scripture), status thymolymphaticus (Bering), excessive saturation in carbonic acid, abnormal hyperacidity.

2. Dynamic causes: spasms of the vocal cords (Schultess, Arnott), respiratory insufficiency (Klemm), heavy tongue (Malebranche), ataxia of the phonatory organs, spastic neurosis affecting the coordination of the phonatory apparatus (Kussmaul, Gutzmann), excess of innervation of the phonatory muscles (R. Read), low aptitude for speech (Liebmann), primary ataxia (Hoëpfner), disproportion between speech and thought (Goloubieff, Blume, Gutzmann, Sittig, Froeschels, Liebmann).

3. Psychogenic functional causes: exaggerated attention upon consonants (Stein), lalophobia analogous to hydrophobia (Schultess, Schenk), influence of repressed anxious emotions (Frey, Lau), anxiety psychosis (de Brie), combined conceptions (Kadoleczy, Froeschels, Hoëpfner).

4. Moralising theories: tendency to conceal one’s inner life, neurosis of martyrdom (Aronsohn), conflict between the need for self-assertion and discouragement (Appelt), conflict between unsatisfied demands and the tendency to isolation (Schneider) — psychoanalytic theories: unmetabolised experience, influence of the Oedipus complex.

One may also mention the classification proposed by Missiouri in 1945:

1. Developmental theories: stammering is explained by the influence of special modalities during the development of speech. Stammerers present no constitutional or psychic anomaly.

2. Dysphemia theories: stammering is a symptom marked by a constitutional organic disorder grounded on a hereditary basis, with neurophysiological and biochemical modifications.

3. Neurosis theories: stammering would be the manifestation of a psycho-neuropathic state — thus the stigma of a disorder of emotional accommodation, called in English “emotional maladjustment”.

The particular case of left-handers

Several authors have dwelt upon left-handers, who deserve quite special attention. Indeed, disorders of phonation are particularly numerous among left-handers — without these necessarily being stammering. Nonetheless, the first statistics established by Sirobel, Sole and Stier report figures oscillating between 6.6 and 8.5% of stammerers among left-handers.

It is now classically admitted that left-handers should under no circumstances be thwarted in the use of their movements, under pain of seeing more or less rapidly the appearance of a stammer, or at the very least a disorder of speech. Thus, left-handers re-educated by requiring the permanent use of the right hand will very rapidly experience difficulty in speaking, and soon find themselves caught up in increasing difficulties which may extend to stammering. Everything stops as soon as the forced re-education ceases.

The explanation of this predisposition to stammering offered by left-handers remains to be found. Strier, Slosse, Siemens, Burr, Bayley, Kelson, Thomas Clark explain it by a struggle which would intervene between their left and right phonatory centres.

III. Clinical study

Stammering manifests itself by a disorder which appears from the beginning of phonation, made up of spasms more or less marked according to the intensity of the impairment of the disorder — extending as far as the blockage of speech.

These spasms are made up of disordered movements, clonic or tonic, lodged at the level of the muscles of articulation, of phonation or of respiration:

• the clonic form is the one which obliges the stammerer to repeat syllables or words;

• the tonic form is characterised by the difficulty the stammerer has in beginning on certain syllables, or in releasing them in order to pass to the following syllable.

The symptomatology may be schematically split into two: on the one hand, the external somatic symptoms; on the other, the internal psychic symptoms (Seeman). The somatic symptoms group together the disorders of synergy between the respiratory, phonatory and articulatory organs. The psychic symptoms are of considerable importance by the consequences they exercise upon the subsequent conduct of the stammerer. The most frequent sign is logophobia — that is to say, the fear of speaking — which will make of the stammerer a timid being.

IV. Artificial stammering: the delayed feedback test

The experiments of Bernard S. Lee, of John W. Black (Ohio State University) and of R. Azzi, repeated before us by Dr Dupoirieux, bear on “delayed feedback” — the delayed voice — by means of a particular apparatus from the Signal Corps Engineering Laboratories.

Description of the test

The apparatus comprises a recorder equipped with two magnetic heads functioning simultaneously: the first allows recording onto wire; the second, in addition, is a reading head and has the capacity to move on a calibrated horizontal bar — allowing the immediate appreciation of the distance between the two heads and, thereby, of the delay obtained.

The test is conducted as follows: the subject stands before a microphone at 80 centimetres; a listening headset returns his speech to him. When the two magnetic heads are touching, no delay is perceived. Then progressively, at the operator’s discretion, a shift increases as the distance between the two heads grows. The listening intensity is of the order of 80 decibels.

Effects

The first disturbance to appear strikingly is the slowing of the rhythm. Then, very rapidly — when the reader seems to wish to struggle against the considerable slowness of his elocution — there appears a first stumble, then a second; finally, if the test continues, an invincible stammer sets in.

For our part, Dr Dupoirieux had us undergo this test: the discomfort we experienced from it, despite the effort we made not to succumb to it, was such that we stumbled for nearly five hours. Everything seemed to occur as though a phenomenon of remanence subsisted. The proof was thereby given to us of the considerable value of the cochleo-phonatory circuit upon the mode of elocution.

Statistically:

• The disturbances become very considerable when the delay imposed oscillates between 0.10 and 0.20 second, and reach a maximum around 0.15 second.

• For Lee as for Dupoirieux, the explanation of the maximum appearance of the disturbances at this level of delay would be linked to the average duration of the syllable — which for Lee is of the order of 0.20 second (American syllable) and for Dupoirieux 0.15 second (French syllable).

• Not all subjects are equally affected: only 20% reach complete stammering, while in the others only a more or less marked slowing is observed. The 20% “affected” comprise a strong majority of men and children. Women prove more resistant to the test — which confirms the classical observations on the influence of sex.

V. Hypothesis and experiments

The problem posed from the outset: might there not be the possibility of individualising an auricular disorder capable of externalising a phenomenon analogous to that achieved in the demonstration of the delay test?

Before any experimentation, and from the moment of becoming acquainted with the problem posed, we leaned a priori towards an organic anomaly capable of engendering an auditory delay of speech, of the order of 0.10 to 0.20 second. It would present itself in the form of an auditory distortion provoked either by an ear which hears with a certain delay relative to the second, or by a kind of “auditory astigmatism”.

Systematic audiometric examinations

We began by carrying out systematic audiometric examinations of every subject acknowledging a more or less marked stammer. Over fifty cases (thirty of whom were furnished by Miss Dinville’s service at the Hôpital Saint-Michel):

• The subjects of the Hôpital Saint-Michel were all right-handed; among the others, only four were left-handed.

• All the right-handers have a right-sided hypoacusis, without exception.

• The four left-handers have, by contrast, a left-sided hypoacusis.

• This hypoacusis is relative, of little importance, not appreciable at a simple examination, and unrecognised by the individuals themselves, who did not seem troubled by it. It strikes more readily the conversational zone.

The directing ear

Was this anomaly sufficient to explain the auditory delay we sought? We were tempted to believe so. Indeed, in numerous experiments practised on professional singers, we had noted that we obtained — in addition to various disorders — a very significant slowing of the melodic line when an auditory trauma was provoked on the right ear in right-handed subjects, on the left ear in left-handers.

We had moreover noted that no modification was observed if the trauma bore on the opposite ear — that is to say, on the left ear in right-handers, or on the right ear in left-handers. We had thence deduced that there exists a directing ear, as there exists a directing eye:

• the right ear, in right-handers;

• the left ear, in left-handers.

The dazzlement of this directing ear by a pure tone (of 1,900 or 2,000 cycles/second, at 100 decibels for a duration of 60 seconds on average) provokes an auditory trauma sufficient to modify the audiometric curve for a time varying from one minute to some fifteen minutes. As was to be expected, we immediately obtained a slowing of speech. And as soon as the subject endeavoured to struggle against this slowing, there appeared a characterised stammer, identical to the one obtained with the delayed feedback apparatus.

VI. The “transcerebral transfer”

For greater clarity, let us schematise the normal cochleo-phonatory circuit. The sound emitted in speech reaches the directing ear; from there it is directed towards the opposite brain, to an auditory centre neighbouring the phonatory centre. Once the monitoring is complete, the nervous impulse moves towards the phonatory organs.

In the case where the directing ear is not used to govern the phonatory monitoring, this monitoring then falls under the dependence of the opposite ear — that is, for example, in the right-hander, of the left ear. The sound reaches the left ear, is conducted to the right brain, at the level of the auditory centre of understanding. Once the monitoring is complete, it must reach the left phonatory centre (motor side), from which the process continues in the direction of the phonatory organs.

The essential difference between the two processes envisaged resides in the “transcerebral transfer” of auditory monitoring onto the opposite phonatory centre. Either it does so directly (right directing ear, via the left brain); or it reaches it by way of the auditory centre of the opposite brain. This time of “transcerebral transfer” seemed bound to be an organic disorder sufficient to explain the delay of audition upon speech.

Measurement of the transfer

To measure it, we proceeded as follows:

1. First, by having a defined text read, of which one knows the number of syllables, without inducing any auditory disturbance; the duration is timed.

2. Then, the directing ear is neutralised, producing a slowing whose value may be calculated.

3. Knowing this last value, it suffices to impose upon the directing ear a delay sufficient to obtain the same slowing in the rate of speech: this delay is the one which corresponds to the time of cerebral transfer.

This measurement is easy and quick to obtain; it requires practically no special apparatus. The last stage — that of the delayed feedback, in fact, bearing upon the directing ear — we investigated by means of a long garden hose 110 metres in length, having been unable to obtain the Bernard S. Lee apparatus; lateral perforations were made along the length of the hose, in such a way as to produce the desired delay times.

Results

• When the latency time remains below 1/10 of a second, the subject — upon whom an auricular inversion is imposed — becomes a bradylalic stumbler. He will speak slowly, searching for his words in an embarrassed babble.

• When the latency time is between 1/10 and 1/20 of a second, the subject submitted to the test reproduces the stammerer — this phenomenon appearing with maximum clarity when the imposed delay is 1/15 of a second.

• When the delay exceeds 1/20 of a second, the subject becomes a bradylalic, who remains very different from the bradylalic stumbler. Indeed, the subjects of this last group speak with a slowed but homogeneous rhythm, without hesitation. And when the test is prolonged, by imposing a delay of the order of 1/8 of a second, the elocution seems to improve for the listener — the voice becomes more nuanced, the subject giving the impression of speaking as in the echo of a large hall.

These results are interesting because they bring into striking relief the personal and individual factor in the genesis of stammering. There is thus only a relatively restricted proportion who — placed in the conditions of a physiological delayed feedback — produce the picture of the typical stammerer.

VII. Implications

The demonstration of this “transcerebral” transfer allows, in large measure at the least, the explanation of the aetiology of stammering. Our opinion is that there exists — at the very least in the cases we have encountered in the course of this work — an organic origin capable on its own of explaining stammering. Taking up the earlier works, the existence of the auricular disorder described seems to bring plausible solutions to several enigmas:

The influence of age

We have seen that it is with maximum frequency that stammering appears between 3 and 5 years. It is the age at which speech takes a great place in the life of the child, where his audition-phonation circuit is still very fragile. It is also the age at which the child presents with maximum frequency afflictions of his ear — leaving as their only sequel a disorder often of little importance in the cochleo-phonatory circuit.

For our part, we have had occasion to examine a young girl afflicted with serous otitis who presented a spectacular stammer in consequence of this affection — a stammer which disappeared at the same time as the otitis was healed.

The influence of sex

The resistance to experimental stammering was already an explanation of the statistical disproportion which exists between stammering in men and in women. We recall that, in broad terms, a proportion varying according to authors from 5 to 8 against 1 is admitted.

We have studied spectrographically the female spoken voice. Contrary to the male voice, the spectrum of a female voice is very rich in high harmonics, in a broad band exceeding 2,000 cycles/second. Now — we have already noted this in studying this phenomenon in the singer — the presence of a sheaf of harmonics located beyond 2,000 cycles/second makes auditory monitoring possible by bone conduction. This could be, in the woman, a mechanism of compensation in face of the possible fragility of the aerial cochleo-phonatory circuit.

Conclusion

This communication is only a first stage. It brings elements of response to an old problem, by proposing an organically grounded hypothesis of stammering on the basis of a subtle auditory anomaly of the directing ear — an anomaly which, by disturbing the cochleo-phonatory circuit, produces an effect equivalent to that of experimental delayed feedback.

The directing ear, of which we here establish the notion, opens an extended field of research. It invites us to take up again the study of dyslateralities, of disorders of language, of failures of communication — under the angle of a precise cybernetic mechanism, the disturbance of which suffices to account for clinical pictures hitherto considered purely neurotic.

The therapeutic consequences of this discovery will form the subject of later communications. Let us only say, here and now, that the re-education of the stammerer through the ear — and more precisely through specific work upon the directing ear — appears to impose itself as the most scientifically grounded way to approach this disorder which has so resisted the classical approaches.

— Dr Alfred A. Tomatis. Offprint, June 1955.