Spectra of the voluntary first cough sounds.

The voluntary cough sounds recorded according to Korpas and Sadlonova-Korpasova were sampled at a frequency of 20.000Hz and spectra of six consecutive windows of 50ms were estimated. To digitize signals an autotrigger mode was used. The subjects were healthy volunteers as well as patients with chronic bronchitis, asthma, bronchial carcinoma (growing intraluminarly in the 1st or in the 2nd or in the 3rd order bronchi), emphysema, laryngeal nerve paralyzis or laryngotomy. The duration of averaged cough sounds of patients was longer than that of healthy volunteers. The mean power of the spectra in the successive windows showed different patterns in the same group. In the third window of healthy volunteers (0.10 s-0.15 s) a high modulus broad bandwidth (between 1-2 kHz) spectrum was found which was considered as a bronchial "flute", and was probably related to the lowest resistance as well as to the velocity of airflow of cough manoeuvre. This pattern appeared with a delay and/or it was changed in the diseased groups compared to the healthy volunteers. Due to this delay, the spectra of the fifth window (0.20 s-0.25 s) showed somewhat higher harmonics (400-800 Hz) in the patients with chronic obstructive pulmonary diseases (COPD), carcinoma and laryngeal nerve paralyzis than in healthy volunteers. In emphysematous patients in the first (0.00-0.05 s), in the third (0.10-0.15 s) and in the fifth (0.20-0.25 s) windows the fundamental frequency was low (156-176 Hz) compared to that of the other groups. The paralyzed vocal cords functioning as an added resistance to the expiratory effort caused a phase-shift in the cough patterns, similarly to that seen in COPD patients. Due to the cannula, the spectra of patients having laryngotomy had a lot of high harmonics. They also had peaks nearly identical to that of bronchitic patients because they suffered from serious chronic bronchitis. It was found that by examination the cough spectra of series of voluntary cough sound signals it was possible to distinguish healthy volunteers from patients. This examination would therefore be useful for screening of bronchial diseases.

[Serum ferritin levels in elderly patients]. / Hladina sérového feritínu u chorých vo vyssom veku.

The authors examined, using the enzyme immunometric method, the serum ferritin concentration in 144 patients aged 60 to 93 years and in 26 healthy volunteers aged 22 to 30 years. They divided the group into four sub-groups: A control group of old people, B control group of young people, C patients with malignities and D patients with various diseases affecting the serum ferritin level. The authors confirmed the significant difference in the serum ferritin concentration between the two control groups (higher concentration in old people). A significant difference in the ferritinaemia in relation to sex (lower in females) was found only in the group of young people. In malignities the serum ferritin level is higher than in the control group, however, on account of the great scatter of values serum ferritin is not a suitable marker of neoplastic growth. Values lower than 30 ng/ml can be conciderend an unequivocal sign of sideropenia; values considered normal in the middle-aged population do not rule out sideropenia in advanced age.

The origin of cough sounds.

We have analyzed the origin of the first and second cough sounds recorded by tussiphonography. About 10,000 tussiphonograms were performed in about 1,000 healthy and diseased subjects. Changes in the first cough sound are due to pathological processes in the airways, for example, the presence of mucus or acute inflammatory disease. The first cough sound may then become divided. In bronchial asthma the first sound is also abnormal because of the narrowed airways. The origin of the second sound becomes clear by its absence in patients after laryngectomy or in those with paralysis of the vocal folds. The reappearance of the second cough sound may indicate rehabilitation of the vocal folds. With laryngotracheitis there is a pattern of multiple sounds. In patients with cough of psychogenic origin, the second sound is absent and cough sounds "bovine". Treatment of patients with bronchodilating drugs did not improve their pathological cough sounds in spite of improvement in airway obstruction.