o Maurizi

Generation of human auditory steady-state responses (SSRs). I: Stimulus rate effects

Auditory evoked responses were recorded in 16 normally hearing subjects in order to investigate the mechanisms underlying the generation of the 40 Hz steady-state response (SSR). In the first part of our study, auditory potentials were evoked by 0.1 ms clicks presented at 105 dB p.e. SPL with repetition rates of 7.9 (to obtain middle latency response, MLR), 20, 30, 40, 50, 60 Hz. In each subject predictions of the responses recorded at stimulus repetition rates of 30, 40, 50, 60 Hz were synthesized by superimposing MLRs at suitable time intervals. The calculated mean amplitude/rate and phase/rate functions behaved similarly for the recorded and predicted curves, showing the highest amplitude at 40 Hz and a linear increase of phase values when increasing the stimulus rate. Nevertheless the synthetic curves closely predicted amplitude and phase values of the recorded responses only at 40 Hz. At frequencies below 40 Hz, the mean amplitude of the predicted curve was lower than that of the recorded one while at frequencies above 40 Hz the mean amplitude was higher. Predicted phase values were found lagging at 30 Hz, and leading at 50 Hz and 60 Hz in comparison to phase values calculated on the recorded responses. Our findings suggest that a model based on the linear addition of transient MLRs is not able to adequately predict steady-state responses at stimulus rates other than at 40 Hz. Other mechanisms related to the recovery cycle of the activated system come into play in the steady-state response generation causing a decrease in amplitude and an increase in phase lag when increasing the stimulus repetition rate.

Generation of human auditory steady-state responses (SSRs). II: Addition of responses to individual stimuli.

In order to investigate the generation of the 40 Hz steady-state response (SSR), auditory potentials evoked by clicks were recorded in 16 healthy subjects in two stimulating conditions. Firstly, repetition rates of 7.9 and 40 Hz were used to obtain individual middle latency responses (MLRs) and 40 Hz-SSRs, respectively. In the second condition, eight click trains were presented at a 40 Hz repetition rate and an inter-train interval of 126 ms. We extracted from the whole train response: (1) the response-segment taking place after the last click of the train (last click response, LCR), (2) a modified LCR (mLCR) obtained by clearing the LCR from the amplitude enhancement due to the overlapping of the responses to the clicks preceding the last within the stimulus train. In comparison to MLRs, the most relevant feature of the evoked activity following the last click of the train (LCRs, mLCRs) was the appearance in the 50-110 ms latency range of one (in 11 subjects) or two (in 2 subjects) additional positive-negative deflections having the same periodicity as that of MLR waves. The grand average (GA) of the 40 Hz-SSRs was compared with three predictions synthesized by superimposing: (1) the GA of MLRs, (2) the GA of LCRs, (3) the GA of mLCRs. Both the MLR and mLCR predictions reproduced the recorded signal in amplitude while the LCR prediction amplitude resulted almost twice that of the 40 Hz-SSR. With regard to the phase, the MLR, LCR and mLCR closely predicted the recorded signal. Our findings confirm the effectiveness of the linear addition mechanism in the generation of the 40 Hz-SSR. However the responses to individual stimuli within the 40 Hz-SSR differ from MLRs because of additional periodic activity. These results suggest that phenomena related to the resonant frequency of the activated system may play a role in the mechanisms which interact to generate the 40 Hz-SSR.

Serum levels of folate, homocysteine, and vitamin B12 in head and neck squamous cell carcinoma and in laryngeal leukoplakia.

The authors evaluated serum levels of folate, homocysteine, and vitamin B12 in patients with head and neck squamous cell carcinoma (HNSCC) and in patients with laryngeal leukoplakia, a well known preneoplastic lesion.

CO2 laser subtotal arytenoidectomy and posterior true and false cordotomy in the treatment of post-thyroidectomy bilateral laryngeal fixation in adduction

Abstract A total of 39 patients with bilateral post-thyroidectomy vocal cord paralysis in adduction underwent CO2 laser subtotal arytenoidectomies with removal of the posterior third of the false and true vocal cords. Total airway resistance (Rtot) evaluated before and 4–10 months after surgery showed marked preoperative impairment before and significant improvement after surgery (P < 0.05). In five patients revision surgery was performed due to a progressive impairment of respiratory function. A variable degree of voice breathiness was observed after surgery; the maximum phonation time mean values were lower than normal and peak sound pressure levels 63 ± 5 dB. In three cases aspiration was present in the first postoperative days, but swallowing dysfunctions disappeared within 1 week. Subtotal arytenoidectomy with removal of the posterior third of the true and false vocal folds was found to be a satisfactory surgical treatment for bilateral vocal cord paralysis in adduction. However, further research is still needed to define the surgical procedure able to balance respiratory, phonatory and sphincteric functions optimally.

Laser carbon dioxide cordectomy versus open surgery in the treatment of glottic carcinoma: Our results

OBJECTIVE : To analyze oncologic results in patients with glottic cancers treated respectively, by laser CO2 or open surgery, taking into account specific-disease survival, rate of locoregional recurrences, and their salvageability. STUDY DESIGN : Retrospective study of 198 patients treated from January 1993 to June 2002 in the department of otorhinolaryngology at a Catholic university in Rome. METHODS : Glottic carcinoma were treated by laser CO2 cordectomy in 132 patients (group 1) and by open surgery in 66 patients (group 2). The statistical analysis was performed by Kaplan Meyer method, log rank test, and x 2 , test. RESULTS : The log-rank test points out significant differences between the 2 groups regarding specific-disease survival; no differences were found for disease-free survival. Within group 1, 16 patients developed local failure, which was retreated in 6 cases with laser surgery; in 9 (6.8%) with total laryngectomy, only 1 case was inoperable. In this group, 10 patients (62.5%) were salvaged. Within group 2, 18 patients developed local recurrences, which was retreated in 14 (21.21%) cases with total laryngectomy; the other 4 cases were not suitable for surgery. Of these 18, 8 patients (44.5%) were salvaged. CONCLUSIONS AND SIGNIFICANCE : Our results show significant differences between the 2 groups concerning the specific-disease survival and the salvageability of local recurrences. In fact, in group 1 we found a higher salvage rate and a lower incidence of total laryngectomy. As already suggested, laser therapy leaves the laryngeal cartilaginous framework intact, avoiding the spread of the tumor out of laryngeal organ and resulting in a more favorable oncologic outcome.

Oncological and functional outcome of conservative surgery for primary supraglottic cancer

Abstract The aim of this study was to verify the oncological and functional outcome of conservative surgical treatment of primary supraglottic squamous cell carcinoma (SGSCC) and related neck disease in order to verify the effectiveness of supraglottic laryngectomy (SL) and the validity of an “observation” policy in the control of clinically negative (N0) necks. Of a total of 252 consecutive patients affected by primary SGSCC seen between 1975 and 1990 at the Department of Otolaryngology of the University of Perugia (1975–1987) and the Catholic University of the Sacred Heart of Rome (1988–1990), a subset of 132 patients treated with classical SL was evaluated after presenting sufficient clinicopathological data and a follow-up period of at least 5 years. Tumors were staged according to the 1992 UICC TNM classification and grouped into stages I-II (n = 94) and III-IV (n = 38). Comprehensive neck dissections were performed only in the clinically positive (N+) necks (25/132 cases), while in the clinically N0 ones (107/132 cases) an “observation” policy under strict follow-up conditions was adopted. After primary surgery, the 5-year relapse-free survival (RFS) was 74%. The RFS was 80% for T1-2 disease and 65% for T3. The RFS was 80% for stages I-II tumors and 71% for stages III-IV. The actual 5-year overall survival (OS) was 89% for T1-T2 tumors and 67% for T3 disease or 93% for stages I-II and 69% for stages III-IV. The OS was 89% for N0 neck and 73% for N+. The 5-year-metastasis-free survival (MFS) was 83% for N0 patients, 74% for N+, 84% for T1-T2 N0, 71% for T1-T2 N+, 81% for T3 N0 and 68% for T3 N+. In all, SL was found to be highly effective in the management of primary SGSCC. In the presence of clinically N0 neck “observation” under strict follow-up with therapeutic comprehensive neck dissection for delayed nodal recurrence, SL was suitable for controlling the neck cancer, as well as for salvaging recurrent disease. Bilateral elective, selective or functional neck dissection in every instance of supraglottic cancer was best performed only in those SGSCC patients who were more likely to have occult nodal disease on the basis of biological factors and imaging data.

Verrucous squamous cell carcinoma of the larynx : diagnostic and therapeutic considerations

The clinical findings, histopathology, management and outcome of 31 patients with verrucous squamous cell carcinoma of the larynx (VSCC) are discussed. Laryngeal VSCC is a rare, highly differentiated variant of SCC and has specific morphological features and clinical behavior. A close liaison between the laryngologist and pathologist is needed to formulate a correct diagnosis, because this tumor appears to be malignant clinically and histologically benign. A low-power magnification of multiple large specimens, including the deep margins of the lesion, is required in order to differentiate VSCC from keratosis, verruca vulgaris or SCC with verrucous appearance, and to detect underlying microscopic foci of invasive SCC within or adjacent to a verrucous carcinoma. Long-lasting hoarseness was the most common symptom as the glottic region was the most common site of VSCC. Presumed clinically positive N1 lymph nodes were observed in the necks of 7 patients, but none had metastatic disease on histopathological study. Surgery alone was the most effective form of treatment, as it allowed a good outcome of all treated patients. Surgery plus radiotherapy was associated with an early recurrence and a poor outcome in 2 of 7 patients treated. The generally “benign” behavior of VSCC allows for conservative surgery, with complete endoscopic resection using the carbon dioxide laser representing a more conservative surgical approach. Neck dissection is not indicated due to the non-metastatic behavior of this tumor.

Auditory brainstem responses in the aged.

The auditory brainstem responses (ABR) in a group of 74 aged subjects (60-80 years), affected by presbycusis were evaluated for presence of a retrocochlear involvement. The comparison of results from subjects with presbycusis with those from normally-hearing elderly subjects, and young subjects, affected by a cochlear sloping hearing loss, revealed that the latency increase of ABR observed in presbycusis is mainly correlated to the audiometric shape of the hearing loss and not to age per se.

Pilot Phase IIA Study for Evaluation of the Efficacy of Folic Acid in the Treatment of Laryngeal Leucoplakia

It has been previously observed that patients with head and neck squamous cell carcinoma or with laryngeal leucoplakia present a significant reduction in plasma folate levels. The current Phase IIA pilot study assessed the effectiveness of folic acid as a chemopreventive agent in patients affected by glottic laryngeal leucoplakia,

Relationships between middle latency auditory responses (MLR) and speech discrimination tests in the elderly

74 subjects aged between 60 and 80 years underwent tonal audiometry, speech discrimination tests (phonetically balanced words, normal sentences and compressed sentences) and middle latency responses (MLRs) in order to evaluate possible correlations between behavioural and electrophysiological tests. The results showed that in elderly patients normal sentences are better understood than phonetically balanced words, that performances decrease dramatically when listening conditions became difficult, that auditory threshold seems to influence speech discrimination scores more than does age per se. MLRs seem to be unaffected both by age and by auditory threshold and Pa occurrence is a more reliable parameter than its latency. No correlation between speech discrimination tests and MLRs could be observed; on the contrary in the presence of abnormal speech discrimination tests the MLRs were almost normal and vice versa.