The evaluation of EEG response to photic stimulation in normal and diseased subjects.

In this paper, our aim is to determine two photic stimulation frequencies, which would represent normal and diseased subjects, separately. Following features were extracted for this aim; linear prediction coefficients (LPC), subband wavelet entropy (SWE), subband wavelet variance (SWV), and relative power (RP). After extracting related features, analysis of variance (ANOVA) statistical test was used for the statistical evaluation of these features. According to the obtained results, wavelet transform-based entropy gave the best results to determine the representing stimulation frequencies. As a result, 29 Hz stimulation frequency was determined as the most representative frequency for normal subjects, whereas 8 Hz stimulation frequency was determined as the most representative frequency for diseased subjects.

The programmable ECG simulator.

This paper reports the design and development of Digital Signal Controller (DSPIC)-based ECG simulator intended to use in testing, calibration and maintenance of electrocardiographic equipment, and to support biomedical engineering students' education. It generates all 12 healthy ECG derivation signals having a profile that varies with heart rate, amplitude, and different noise contamination in a manner which reflects true in vivo conditions. The heart rate can be set at the range of 30 to 120 beats/minute in four steps. The noise and power line interference effects can be set at the range of 0 to 20 dB in three steps. Since standard commercially available electronic components were used to construct the prototype simulator, the proposed design was also relatively inexpensive to produce.

A multivariate analysis of objective voice changes after thyroidectomy without laryngeal nerve injury.

OBJECTIVE: To evaluate the impact of thyroidectomy and the possible effects of factors such as patient sex, operation type, and surgeon experience on objective voice parameters of patients undergoing thyroidectomy without laryngeal nerve injury. DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Thirty-six patients undergoing primary thyroidectomy because of thyroid disease. MAIN OUTCOME MEASURES: The effect of thyroidectomy on voice was examined by recording the voices of the patients before and 1 week after thyroidectomy. The Multi-Dimensional Voice Program was used for capturing and analyzing the voice samples. RESULTS: On postoperative examination of objective voice changes, thyroidectomy had no multivariate effect on the combination of voice parameters. Patient sex, type of surgery, and surgeon experience had no effect on the combination of voice parameters before and after thyroidectomy. Regardless of within-patient factors (type of surgery, patient sex, and surgeon experience), 4 acoustic parameters (highest fundamental frequency, standard deviation of average fundamental frequency, phonatory average fundamental frequency range in semitones, and degree of subharmonics) significantly decreased after thyroidectomy (P < .05). Although they tended to be worse, none of the acoustic parameters showed significant changes in male patients. However, significant changes in some of the acoustic parameters of female patients were observed. Highest fundamental frequency, standard deviation of average fundamental frequency, phonatory average fundamental frequency range in semitones, absolute jitter, relative average perturbation, pitch perturbation quotient, shimmer in decibels, percentage of shimmer, amplitude perturbation quotient, noise to harmonic ratio, and degree of subharmonics values were all lower in female patients after thyroidectomy (P < .05). CONCLUSIONS: Voice changes may occur after thyroidectomy without any evident laryngeal injury, and deterioration and amelioration of acoustic parameters can be observed to occur differently among male and female patients. Preoperative and postoperative objective voice analyses may be helpful in documenting voice changes.

Wavelet transformation based watermarking technique for human electrocardiogram (ECG).

Nowadays, watermarking has become a technology of choice for a broad range of multimedia copyright protection applications. Watermarks have also been used to embed prespecified data in biomedical signals. Thus, the watermarked biomedical signals being transmitted through communication are resistant to some attacks. This paper investigates discrete wavelet transform based watermarking technique for signal integrity verification in an Electrocardiogram (ECG) coming from four ECG classes for monitoring application of cardiovascular diseases. The proposed technique is evaluated under different noisy conditions for different wavelet functions. Daubechies (db2) wavelet function based technique performs better than those of Biorthogonal (bior5.5) wavelet function. For the beat-to-beat applications, all performance results belonging to four ECG classes are highly moderate.

Laryngeal findings and voice quality in Sjögren's syndrome.

OBJECTIVE: The effect of Sjögren syndrome (SS) on perceptual ratings of the laryngeal findings using the Reflux Finding Score (RFS) and the Reflux Symptom Index (RSI) and the objective voice quality using Jitter (JITT), Pitch Period Perturbation Quotient (PPQ), Shimmer (Shim), Amplitude Perturbation Quotient (APQ) and Noise-to-Harmonic Ratio (NHR) was examined. METHODS: Seventy-seven patients with SS and seventy-seven healthy individuals for the control group were studied. The Reflux Symptom Index (RSI); nine-item outcomes instrument for assessment of symptoms in patients and the Reflux Finding Score (RFS), eight-item laryngoscopic-based scale for evaluation of laryngeal findings in patients were realised. The Multi Dimensional Voice Program (MDVP) was used for capturing and analysis of the voice samples. For comparison of all parameters of patients and control group subjects, the independent sample t-test was used. RESULTS: The difference of RSI and RFS between patients with SS and control subjects was statistically significant. The difference of voice quality parameters between patients with SS and control subjects expect NHR were statistically significant. CONCLUSION: There is a significant association between SS and a variety of laryngeal pathologies. The SS patients with reflux symptoms and voice problems must be examined by an ENT specialist and local laryngeal manifestations of SS can be treated symptomatically.