Kazuhiko Mashima

Normalized noise energy as an acoustic measure to evaluate pathologic voice

In order to evaluate noise components included in pathologic voice signals, a novel acoustic measure, normalized noise energy (NNE), is proposed and its effectiveness for the detection of laryngeal pathologies is investigated with 250 vowel samples spoken by 64 control (normal) subjects and 186 patients with various laryngeal diseases. The NNE is automatically computed from the voice signals using an adaptive comb filtering method performed in the frequency domain. Experiments with the voice samples show that the NNE is especially effective for detecting glottic cancer, recurrent nerve paralysis, and vocal cord nodules. Specifically, when glottic cancer is represented in terms of the T classification adopted by the UICC (Union Internationale Contre le Cancer), glottic T2-T4 cancer can be perfectly discriminated from normal samples, but 22.6% of patients with glottic T1 cancer are incorrectly classified as normal, with an error rate of 9.4% for normal subjects.

Lymphoscintigraphy of Head-and-Neck Cancer

To achieve the visualization of regional lymph nodes by lymphoscintigraphy, 21 patients with head-and-neck cancer were studied with the aid of 99mTc-labeled rhenium sulfur colloid (99mTc Re). Four injection sites were selected; the injections were given into the subcutaneous tissue of the parietal area of 11 patients, into the submucosa of the retromolar area of 6 patients, into the subcutaneous tissue of the postauricular area of 2 patients, and into the thyroid glands of 2 patients. Lymphoscintigraphy was done three hours after the injection. The cervical regions were visible in 85.7% of the patients on the affected side and in 90.5% on the healthy side. The visualization comprised the following regions: submental, submandibular, deep cervical, accessory, and supraclavicular regions. In total, 102 nodes were visualized on the affected side (average 4.8 per patient) and 110 nodes in the healthy side (average 5.5). Histologically, 15 of 21 patients had lymph nodes metastases and 6 did not. Of these 21 patients, 66.7% (14/21) had confirmed lymph node metastases in the visualized regions. This technique appears to be a relatively easy and efficient method of imaging the regional lymph nodes in head-and-neck cancer both before treatment and after neck surgery.