Isolated word recognition of silent speech using magnetic implants and sensors.

There are a number of situations where individuals wish to communicate verbally but are unable to use conventional means-so called 'silent speech'. These include speakers in noisy and covert situations as well as patients who have lost their voice as a result of a laryngectomy or similar procedure. This paper focuses on those who are unable to speak following a laryngectomy and assesses the possibility of speech recognition based on a magnetic implant/sensors system. Permanent magnets are placed on the tongue and lips and the changes in magnetic field resulting from movement during speech are monitored using a set of magnetic sensors. The sensor signals are compared to sets of pre-recorded templates using the dynamic time warping (DTW) method, and the best match is identified. Experimental trials are reported for subjects with intact larynx, typically using 500-1000 utterances used for speaker dependant training and testing. It is shown that recognition rates of over 90% are achievable for vocabularies of at least 57 isolated words: sufficient to drive command-and-control applications.

Development of a (silent) speech recognition system for patients following laryngectomy.

Surgical voice restoration post-laryngectomy has a number of limitations and drawbacks. The present gold standard involves the use of a tracheo-oesophageal fistula (TOF) valve to divert air from the lungs into the throat, which vibrates, and from this, speech can be formed. Not all patients can use these valves and those who do are susceptible to complications associated with valve failure. Thus there is still a place for other voice restoration options. With advances in electronic miniaturization and portable computing power a computing-intensive solution has been investigated. Magnets were placed on the lips, teeth and tongue of a volunteer causing a change in the surrounding magnetic field when the individual mouthed words. These changes were detected by 6 dual axis magnetic sensors, which were incorporated into a pair of special glasses. The resulting signals were compared to training data recorded previously by means of a dynamic time warping algorithm using dynamic programming. When compared to a small vocabulary database, the patterns were found to be recognised with an accuracy of 97% for words and 94% for phonemes. On this basis we plan to develop a speech system for patients who have lost laryngeal function.

The association of subjective nasal patency with peak inspiratory nasal flow in a large healthy population.

This study, performed on 303 healthy volunteers, tested the null hypothesis that normal subjects were unable to assess their nasal patency when compared with objective measurement using peak inspiratory nasal flow rate (PINFR). Subjective assessments were made on a categorical scale and PINFR was measured using an In-Check meter. Analysis of variance showed that the peak inspiratory nasal flow rate, when grouped by the subjective scores, was significantly different.

Genetic analysis of head and neck squamous cell carcinoma and surrounding mucosa.

OBJECTIVE: Comparative genomic hybridization was performed on head and neck squamous cell carcinoma and surrounding mucosa to determine whether common chromosomal aberrations could be detected that would predispose an individual to developing a second primary tumor. DESIGN: Biopsy specimens were taken from 19 patients with squamous cell carcinoma of the head and neck, 3 samples from each person: 1 specimen from the tumor site and 1 each from 1 and 5 cm from the macroscopic tumor margin. Samples were snap frozen in liquid nitrogen. A portion of each distant sample and tissue taken from immediately adjacent to the site of the tumor specimen were sectioned and stained with hematoxylin-eosin, either to search by light microscopy for tumor cells or signs of dysplasia in the distant samples, or to determine whether the tumor specimen had substantial non-tumor cell content. Tissue adjacent to the tumor biopsy site was used because the biopsy specimens were relatively small. Comparative genomic hybridization was performed on all samples. SUBJECTS: Nineteen patients with newly diagnosed carcinomas of the head and neck. RESULTS: The tumor biopsy specimens showed no substantial nontumor cell content, and the distant specimens were all histologically normal. The tumors showed multiple mutations: mean (SD) number of deletions, 5.4 (4.3); amplifications, 5.2 (4.6). Deletion of chromosome 3p was seen in 13 of 19 cases and was associated with amplification of 3q in 10 cases. No mutations were seen in the distant biopsy specimens. CONCLUSIONS: Frequently occurring chromosomal aberrations were seen in the tumor cells, suggesting a key role for these mutations in tumor development. Screening histologically normal upper aerodigestive tract mucosa with comparative genomic hybridization does not provide information on early genetic events that predispose a patient to developing a second primary tumor.

The effect on nasal resistance of an external nasal splint during isometric and isotonic exercise.

The now commonplace wearing of external nasal splints by sportsmen and athletes has never been scientifically evaluated. The present study looks into the effect of both isometric and isotonic exercise on nasal resistance and examines if this is altered by the wearing of an external nasal splint. Twenty subjects who did not suffer from rhinitis were tested. Nasal resistance measurements were recorded using an anterior rhinomanometer before and after exercise, with and without an external nasal splint. Pulse and blood pressure were measured using a Criticare Inc. model 508 physiological monitor before and after exercise. Significant changes were observed in pulse (P < 0.001) and both systolic (P < 0.002) and diastolic (P < 0.001) blood pressure in response to isotonic exercise and pulse (P < 0.0001) and diastolic blood pressure (P < 0.0006) in isometric exercise. Significant differences were seen in nasal resistance when the splint was applied before (P < 0.001) and after exercise in both groups (P < 0.003). No significant difference was observed between the post-isotonic exercise groups with and without the splint (P = 0.167) but significant differences were seen in the isometric group (P < 0.0001). External nasal splints decrease nasal resistance at rest but are of little proven value when performing isotonic exercise however significantly reduce nasal resistance during isometric exercise.

Serum vascular endothelial growth factor in patients with head and neck squamous cell carcinoma.

Vascular endothelial growth factor (VEGF) is a key pro-angiogenic cytokine expressed by most human tumours. Two isoforms, VEGF121 and VEGF165, are soluble and can be assayed in serum. Serum VEGF has been shown to be significantly raised in patients with solid tumours and shows some promise as a potentially useful tumour marker. Serum levels of VEGF were assayed in 52 patients with untreated head and neck squamous cell carcinoma (HNSCC) and 104 healthy controls. Serum VEGF is significantly raised in patients with HNSCC (P < 0.001), but there was no association with either tumour stage or specifically the presence of nodal metastases. Sixteen patients (31%) had a higher serum VEGF than 95th centile of controls, suggesting that serum VEGF measurement is of little practical use as an initial diagnostic tool. The finding that patients with HNSCC have significantly raised serum VEGF probably relates to enhanced platelet aggregation in these patients.

Angular cheilitis after tonsillectomy.

The operation of tonsillectomy requires the oral cavity to be held open mechanically in an unconscious patient, and intra-oral instrumentation to occur. Angular cheilitis may arise as a result of this after operation. This can cause morbidity and delay the re-establishment of a normal diet. The aim of this study was to identify what factors increase the likelihood of developing this problem postoperatively. Sixty patients were randomly selected in a prospective manner. Preoperative, intraoperative and postoperative variables were recorded. The frequency of development of postoperative angular cheilitis was recorded. The prevalence of the condition was related to the prerecorded variables. Parametric analysis showed that the chance of developing angular cheilitis was directly related to the use of diathermy haemostasis (P = 0.05). Logistic regression analysis showed that the odds ratio of developing this complication if diathermy was used is 3.5 (95% confidence intervals 0.99, 12.4) and operation difficulty may also be a relevant variable. No other recorded variables were found to be significant.

Effect on nasal resistance of an external nasal splint and isotonic exercise.

OBJECTIVES: The now commonplace wearing of external nasal splints by sportsmen and athletes has never been scientifically evaluated. The present study looks into the effect of isotonic exercise on nasal resistance, and examines whether this effect is altered by the wearing of an external nasal splint. METHODS: Twenty subjects not suffering from rhinitis were tested. Nasal resistance measurements were recorded using an anterior rhinomanometer before and after isotonic exercise with and without an external nasal splint. Pulse and blood pressure were measured before and after exercise. RESULTS: Significant changes were observed in pulse (p < 0.001) and both systolic (p < 0.002) and diastolic (p < 0.001) blood pressure in response to exercise. Significant differences were seen in nasal resistance when the splint was applied (p < 0.001) and after exercise (p < 0.003). No significant difference was observed after exercise when the splint was worn (p = 0.167). CONCLUSIONS: External nasal splints decrease nasal resistance at rest but are of little value during isotonic exercise.

Nasal pH measurement: a reliable and repeatable parameter.

The nasal mucosal pH is approximately 5.5-6.5, and increases in rhinitis to 7.2-8.3. This knowledge has not led to the widespread measurement of the nasal mucosal pH as an objective clinical parameter. The purpose of this study was to assess whether repeatable measures of nasal mucosal pH could be obtained in the clinical setting. Fifty-four adults without nasal symptoms were prospectively recruited. Using a semi-disposable antimony pH catheter, the nasal mucosal pH was measured in four specific areas of the nose and each reading repeated three times. The patients' age, sex, smoking habits, nasal anatomical variation and clearest nostril at the time of measurement were also recorded. The data shows that it is possible to obtain reliable and repeatable values for the pH of the nasal mucosa (Spearman-Brown R = 0.84). Analysis shows there is no significant difference between septal and turbinate mucosal pH. Subset analysis implies that nasal mucosal pH is higher in men then women (P < 0.05). The other variables did not affect the nasal mucosal pH significantly.

Recurrent unilateral tonsillitis secondary to a penetrating foreign body in the tonsil.

We report a case of an impacted foreign body in the tonsil presenting as recurrent unilateral tonsillitis. A completely embedded foreign body should be considered in cases of recurrent unilateral tonsillitis.

Giant hamartoma of the oropharynx.

Giant polypoidal hamartomas of the pharynx and oesophagus are rare benign tumours of unknown origin, exceptionally arising from the oropharynx. We report the case of a 74-year-old man who developed sudden nausea and a foreign body sensation. Shortly afterwards he regurgitated a 25 x 3 x 1.5 cm pedunculated fleshy mass, still attached to the inside of his thorat. The patient was anaesthetised, the mass traced to the right tonsillar fossa and adjacent oropharyngeal wall. The pedicle was clamped and the lesion excised. Histology was consistent with a giant oropharyngeal hamartoma. We discuss the pathogenesis and potential complications of this condition. The literature is reviewed.

Candida'the cancer of silastic'.

Candida species have the propensity to colonize and erode into the surface of silastic causing a loss of function. Colonization of silastic tracheo-oesophageal speaking-valves is an important cause of valve failure post-laryngectomy: the exact nature of the colonization is unknown and light microscopic studies have not been reported previously. Microbiological examination of scrapings taken from the colonized oesophageal surface of failed speaking valves was arranged before sectioning for light microscopy. Conventional ultrathin sectioning of silastic was difficult, therefore 15 micrometre sections were cut after cooling the material to -30 degrees C. These sections were then stained with toluidine blue; Candida species taking up the stain. Microbiological examination of the colonies confirmed the predominance of Candida species in the biofilm. Light microscopy of the 15 micrometer sections revealed that the Candida colonies had invaded the silastic. This work demonstrates that the colonization of the silastic valve prosthesis in the oesophageal area is due predominantly to Candida species which actively invade the structure of the silastic. This is an important cause of speaking-valve failure post-laryngectomy.

A multi-observer study examining the radiographic visibility of fishbone foreign bodies.

The use of plain radiographs to localize a suspected fishbone foreign body is the subject of controversy. Accordingly radiographs of 14 species of fishbone, impacted in a soft tissue phantom, were assessed by a series of observers from the ENT department (consultant surgeons, senior registrars and house officers). The agreement was assessed by graphical description of the data and tested by a Spearman's rank correlation test. The overall results showed that, for the clinician, radiography is very useful to detect the bones of: cod, haddock, lemon sole, cole fish, grey mullet and plaice; useful for red snapper, monk fish, gurnard and salmon; and unhelpful in detecting bones from herring, pike, mackerel and trout. The use of radiographs to locate these impacted fishbones can be rationalized in the light of these findings.

Microbial colonization of the Groningen speaking valve and its relationship to valve failure.

Speaking valve failure may be related to biofilm development. An inter-observer validated method of assessing microbial overgrowth in defective prostheses was developed. Two independent observers recorded colonisation of the valves on a 100 mm linear analogue scale in several defined areas. Inter-observer agreement was high in all areas. In vitro opening pressure and derived forward resistances were measured. The relationship between colonization of the valves and the in vitro measurements was investigated. Significant correlations for a two-tailed Spearman's test were recorded between the resistance and microbial colonization of the hinge and oesophageal areas (rs 0.22: P < 0.05, rs 0.25: P < 0.05, n = 80). There was no significant association for resistance and colonization of the tracheal surface, and no significant association between the opening pressure and the colonization. This work suggests that microbial colonization of the prosthesis in the oesophageal and hinge areas is associated with valve failure.

Correlation of subjective sensation of nasal patency with nasal inspiratory peak flow rate.

To determine the relationship between subjective sensation of nasal patency and objective measurement of nasal inspiratory peak flow rate, a longitudinal study was conducted using healthy volunteers. Five healthy medical practitioners, one woman and 4 men, aged 24-34 years, made daily subjective estimations of their sensation of nasal patency on a 10-cm visual analogue scale. This was followed immediately by measurements of nasal inspiratory peak flow rate using a Youlten meter, repeated on at least 25 days per subject. Correlation coefficient and regression lines for subjective nasal patency on nasal inspiratory peak flow rate were calculated. One hundred and sixty nine sets of observations were made, range 25-44 per subject. Each subject showed strong evidence (P < 0.01) of positive correlation between subjective nasal patency score and nasal inspiratory peak flow rate. There was strong evidence (P < 0.001) that different regression lines are needed for different subjects, but no evidence that the lines are not parallel. Subjective sensation of nasal patency is strongly correlated with objective nasal patency, as measured by peak inspiratory flow rate. This relationship varies between individuals. Measurement of nasal inspiratory peak flow rate may be a valuable objective test of nasal patency, and is quick and simple to perform.

Osteomyelitis of the cervical spine following laryngectomy.

Only one case of osteomyelitis of the cervical spine following laryngectomy for carcinoma of the larynx has been reported in the literature to date. We report an unusual case of osteomyelitis of the cervical spine following treatment of laryngeal carcinoma by radiotherapy (RT) and subsequent laryngectomy and discuss the relevant literature.

The radio-opacity of fishbones.

Plain radiographs are often taken to localize fishbones which lodge in the pharynx. In this study a pig's neck was used to determine the radio-opacity of 14 different species of fishbones. Radiographs were taken with bones placed in up to four of the common sites of impaction and assessed on two occasions independently by two previously uninvolved ENT consultants. The visibility of the fishbones was scored. Inter and intra-observer agreement for species and site was determined. There was excellent interobserver agreement at both sessions for species (rs1 = 0.96, P < 0.0001, rs2 = 0.95, P < 0.0001) and site (rs1 = 0.98, P < 0.05, rs2 = 0.95, P congruent to 0.05). Intraobserver agreement for species of fish were similarly significant but not for site. The most opaque bones were cod, haddock, grey mullet and lemon sole. The site most often detected was the laryngopharynx and that most often missed was the tonsil. This study is clinically relevant because it is useful to know which species of fishbone are radio-opaque when clinical examination fails to reveal a foreign body and may clarify the decision to proceed to endoscopy.

The radio-opacity of fishbones--species variation.

Plain radiographs are often taken to localize fishbones which lodge in the oropharynx and hypopharynx, but which are not seen on clinical examination. Fishbones which are thus revealed can then be removed by endoscopy. For a lateral neck radiograph to be useful in excluding a fishbone when mirror examination is difficult or fails to reveal a foreign body, it is important to know which types of fishbone are radio-opaque. We used a pig's neck preparation to simulate a human neck to determine the radio-opacity of the bones of 14 different species of fish eaten in the British Isles. We conclude that only the bones from cod, haddock, cole fish, gurnard, lemon sole, monk fish, grey mullet and red snapper are well seen by soft tissue radiographic techniques.