Peter Kitzing

Initial validation of an indirect measure of subglottal pressure during vowels

Some methods for direct measurement of subglottal pressure during speech are invasive and thus cannot be used on a routine basis. The development of noninvasive techniques is thus desirable, and a simple indirect method for measuring subglottal pressure from records of oral pressure during consonants has recently been proposed and applied to studies of glottal resistance during phonation. In order to bae useful, indirect measurement procedures should be validated by comparisons with direct measurements, and the present experiment was designed for such a comparison. Miniature pressure transducers were used to obtain records of pressure below and above the glottis. Results showed nonsignificant differences and a high correlation between the direct and indirect measurements. This indirect method for measuring subglottal pressure thus appears to provide valid results.

Clinical Applications of Electroglottography

Summary Electroglottography (EGG) is a method to monitor the vibrations of the vocal folds by measuring the varying impedance to a weak alternating current through the tissues of the neck. The paper is an attempt to give a state-of-the-art report of how electroglottography is used in the clinic. It is based on a search of the pertinent literature was well as on an inquiry to 17 well known specialists in the field. The EGG techniques are described and limitations to the method are pointed out. Attempts to document voice quality by EGG are recognized and computerized methods to obtain information about vibratory perturbations and/or the vibratory frequency of the vocal folds are described. The authors personal conclusion is that the EGG signal is especially well suited for measurements of the glottal vibratory period. In the clinic such measurements are useful for periodicity analysis, as a basis for recording intonation contours, and to establish the characteristics of the voice fundamental frequency.

Automatic speech recognition (ASR) and its use as a tool for assessment or therapy of voice, speech, and language disorders.

In general opinion computerized automatic speech recognition (ASR) seems to be regarded as a method only to accomplish transcriptions from spoken language to written text and as such quite insecure and rather cumbersome. However, due to great advances in computer technology and informatics methodology ASR has nowadays become quite dependable and easier to handle, and the number of applications has increased considerably. After some introductory background information on ASR a number of applications of great interest for professionals in voice, speech, and language therapy are pointed out. In the foreseeable future, the keyboard and mouse will by means of ASR technology be replaced in many functions by a microphone as the human–computer interface, and the computer will talk back via its loud-speaker. It seems important that professionals engaged in the care of oral communication disorders take part in this development so their clients may get the optimal benefit from this new technology.

A Photoglottographical Study of the Female Vocal Folds during Phonation

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Pharyngeal function after carotid endarterectomy.

Neurologic deficiencies, with special reference to pharyngeal function, were studied prospectively in 12 patients before and after they underwent carotid endarterectomy. Pharyngeal function was monitored with cineradiography. Five patients developed pharyngeal dysfunction: defective closure of the laryngeal vestibule, epiglottic dysmotility, and pharyngeal constrictor paresis 1 week postoperatively. In 2 patients this dysfunction remained, while in 3 it had resolved 4 weeks after the operation. Pharyngeal dysfunction was more common in patients with preoperative minor stroke and a temporary perioperative carotid shunt and in patients with a long operation time. The registered transient pharyngeal dysfunction may be due to manipulation of the cervical structures including the vagus nerve and the pharynx or due to cerebrovascular damage during the operation. Our findings support careful monitoring of postoperative oral feeding in patients at risk.

Communication aids for people with aphasia

In principle, aphasia is a disability to use language. No wonder therefore, that most aphasiologists both in research and in therapy tend to focus mainly on linguistic function. The most prominent symptom of aphasia usually is a deficiency of speech, and many laymen believe that speech exercises should be the therapy of choice, which is not always correct. However, to those suffering from aphasia their disorder first of all means restricted communication and thereby a risk of becoming isolated. Therefore, besides language and speech therapy, people with aphasia have an urgent need of compensations or substitutes for their loss of communication. The number and variation of available communication aids for aphasia is rapidly increasing, mainly because of almost general use of computerized techniques. The following text wants to draw attention not only to software and hardware useful to aiding communication in aphasia, but also to the large amount of helpful information available from the Internet. Last but not least, access to the Internet as such may become an important tool to breaking isolation. A person with aphasia may need special arrangements and support, however, to be able to use her/his computer to this end, e.g. for e-mailing, web-surfing or chatting. Before the computers came into common use, a number of low-tech devices to aid communication were available. Amongst them may be mentioned letter boards, personal ‘passports’ for presentation of the owner and information about his/her problem, and photo albums used, for example, to raise new topics in a conversation. Comprehensive so-called communication books are described in detail by Millar (1,2). They may contain generalized picture and/or symbol vocabularies, guidance for conversation partners, index pages, etc., besides personal material such as photos, drawings, or newspaper cuttings. For different reasons, well discussed by van de Sandt-Konderman (3), low-tech communication aids for people with aphasia have not become very popular. One reason could be that much of the material is designed to suit mainly children or aims foremost at other types of communication problems than aphasia, such as. dysarthria (see for example (4,5)). Unfortunately this seems to be the case also for a number of high-tech communication aids. These are basically machines that can talk, either by a digitized or by a synthesized speech output. Digitized speech may be used to play back previously recorded entire messages. Synthesized speech has a lower quality but is more flexible, so that new messages may be phrased, as long as the user is able to do this and also to master correct spelling. The input to the aids may be indicated either by text or by graphics such as symbols, icons or pictures. The market abounds with this type of devices and the Swedish Institute for Handicap has listed no less than 36 such electrical speech aids (6 /9). High-tech aids specifically designed for aphasia may be divided in disorder oriented, ‘prosthetic’ systems, aiding specific problems such as those of word finding or sentence construction, and genuine conversation aids aiming at communicative function as a whole (3). Similar to the above mentioned communication books these later aids may be used to fulfil a number of different communicative needs such as presentation, claiming needs, asking questions, raising conversation topics, etc. Typically, these devices consist of a computer showing

Shape and shift of the laryngeal ventricle during phonation

The shape and shift of the laryngeal ventricle during phonation was studied in profile roentgenographs of 41 young males with normal voice function. None of them was a trained singer.From a mean of 14 mm at rest position of the vocal folds and during quiet respiration, the laryngeal ventricle was elongated by about 7 mm when the tone frequency was increased to 325 cps. The height of the laryngeal ventricle was increased from about 3 mm at rest position to about 5 mm at 225 cps. On further increase of the tone frequency the height diminished.During respiration the laryngeal ventricle was generally located at the level of the lower border of the 5th cervical vertebra. During phonation at high pitch the laryngeal ventricle was generally elevated while at low pitch it moved downwards.The elongation of the laryngeal ventricle was due mainly to a forward movement of the anterior border of the ventricle whereas the distance between the posterior border and the cervical column remained unchanged. It is confirmed ...

Arylhydrocarbonhydroxylase Inducibility and Smoking Habits in Patients with Laryngeal Carcinomas

There is considerable evidence that the inducible enzyme aryl hydrocarbon hydroxylase (AHH) plays an important role in the activation of polycyclic aromatic hydrocarbons (PAH) to ultimate carcinogens. In man, a genetic heterogeneity of AHH inducibility has been demonstrated, and correlated to susceptibility to bronchogenic carcinomas following exposure to PAH. We assessed AHH inducibility in a control group of 102 healthy Swedish citizens and in 41 patients with laryngeal carcinomas. Frequencies of the three phenotypes of high, intermediate and low AHH inducibility in our control group; 8.8%, 42.2% and 49%, respectively, did not differ significantly from frequencies found in a white US population. In the laryngeal carcinoma group, there was a statistically highly significant overrepresentation of patients with high AHH inducibility, 36.6%, whereas 43.9% had an intermediate and 19.5% a low level. Most of the patients were heavy smokers. These findings add further support to the concept that susceptibility to PAH-induced carcinomas is associated with high levels of inducible AHH activity.

Endoscopic findings of early stage vocal fold cancer

To describe early cancerous and precancerous lesions of the laryngeal vocal folds as well as of the most common differential diagnoses, based on a series of microlaryngoscopic photographs. Some introductory remarks about terminology and the classification of epithelial lesions of the vocal folds are included. The paper ends with some comments as to the management of epithelial thickenings (or leukoplakias) of the vocal folds. Malignancy should be suspected as long as it has not been ruled out by histologic diagnosis on adequate biopsies, which is the only way to correctly evaluate the character of such lesions. Precancerous lesions should be controlled by regular follow up examinations as carefully as invasive carcinomas (posttreatment), because there is a high tendency for recurrences or for later development of malignancy in these cases.

Transglottal pressure during the laryngeal vibratory cycle

Understanding of the laryngeal vibrations requires knowledge both of the properties of the vocal fold tissues and the aerodynamic forces interacting with the myoelastic ones during each vibratory cycle of the glottis. This paper reports measurements of pressure variations below and above the vocal folds during individual vibratory cycles. Pressure was recorded using miniature transducers placed in the trachea and in the pharyngeal cavity. Information on laryngeal vibratory movements was obtained by simultaneous trans‐illumination and electrical glottography. Egressive airflow was recorded using a pneumotach screen. Results indicate variations in transglottal pressure associated with changes in glottal opening. Subglottal pressure may vary 20%–40% above and below the mean pressure during each cycle, depending on phonation type and intensity level. Pressure variations showed a lag of 0.5‐1 ms in relation to glottal vibratory movements. Influences of vocal tract resonances on subglottal pressure were sometim...