Biomedical subjects

V Pean

Publications and source records attributed to V Pean.

5 recordsLinked to original sources

PubMed2001

A fractal approach to the features of speech consonants.

Fractal dimension (D) quantifies the roughness of a temporal signal and estimates its degree of freedom, allowing a good approach for its fluctuations. This present study of consonants follows the D-assessment of vowels which was presented at the Copenhagen Collegium Meeting. Using a 16 kHz time sampling the D-values of consonants were studied in the consonant-vowel context of the French language. Each consonant was pronounced four times by six males and six females. For D-measurement of long consonants the same method was used, i.e. the dyadic box-counting method and its 10 points of D-measurement (10pD) as that used for vowels. In the aim to approach infinitely small time scales, and to appreciate at least the tendency of the 10-point set, i.e. the D value to which tends this set, the slope of the three last points (3pD) was also calculated. For the plosion part of plosive consonants, a semi-continuous box-counting method devoted to the D-measurement of a short, single-dimension temporal signal was designed. This study consistently demonstrates that (i) there is a significant difference between males and females, as far as voiced and non-plosive consonants are concerned; (ii) plosive consonants are not fractal; (iii) among long consonants, D-value of fricatives are significantly different (p < 0.01), as far as 3pD measurement is considered; and (iv) in the case of nasal consonants [m] and [n], this categorization is efficient for both 3pD and 10pD measurements (p < 0.05). There results will be commented on and discussed with the aim of clinical use.

Adult↗

PubMed1997

[Asynchronous sequential stimulation. A new signal treatment for cochlear implants].

Cochlear implants use a fixed or FO dependent stimulation rate, whatever the sound analysed (vowel or consonant) and its analysis procedure (fixed filters or FFT). We present a procedure which varies as a function of the nature of the input signal. This method is based on FFT analysis using a variable with analysis window. Short windows are applied on the transient part of the signal, providing poor frequency resolution but good time resolution; they accurately permit to follow the speech signal in time during its fast temporal variations. Large windows are applied on the stationary parts of the signal, providing better frequency resolution, but poor time resolution. Transient parts of the speech order this window switching; they are detected using the statistical properties of the FFT; moreover the narrow windowing is coupled with an increase of the stimulation frequency. This strategy has been implemented using the Digisonic cochlear implant software, and clinically assessed on 6 regular cochlear implant users, owing to a consonant-vowel-consonant test. This Asynchronous-Interleaved-Stimulation (AIS) strategy provides the patients with better discrimination than fixed window FFT analysis. The coding protocol are described and results presented.

Acoustic Stimulation↗

PubMed1986

Risk factors associated with AIDS in Haiti.

A total of 121 acquired immunodeficiency syndrome (AIDS) patients diagnosed in Haiti were studied between June 1979 and December 1983. Risk factors were identified in 65% of 34 patients evaluated in a standardized manner since July 1983 and included: bisexuality, 38%; blood transfusion, 21%; and intravenous drug abuse or a spouse with AIDS, 6%. These risk factors were reported by only 20% of the 85 patients studied between June 1979 and June 1983. AIDS patients also reported more frequent parenteral injections prior to the onset of their illness than control subjects (e.g., siblings, friends, sexual partners). Heterosexual activity among female AIDS patients was also greater than in their female controls. It was concluded that, in contrast to the experience reported among Haitians with AIDS in the USA, risk factors are present among most patients with AIDS in Haiti.

Acquired Immunodeficiency Syndrome↗

PubMed1985

The acquired immunodeficiency syndrome in Haiti.

Two hundred twenty-nine patients in Haiti with the acquired immunodeficiency syndrome were studied between 1979 and 1984. The clinical spectrum of the syndrome in Haitians was similar in most aspects to that in patients with the disease in the United States. However, in contrast to findings in the United States, accepted risk factors (bisexuality, blood transfusions, intravenous drug abuse) were identified in only 43% of Haitian patients. Patients in Haiti with and without these risk factors were similar to each other but differed from age- and sex-matched siblings and friends in the number of heterosexual contacts and receipt of intramuscular injections. These latter activities were commoner in patients than in their siblings and friends, and represent potential modes of transmission of infection with the human T-lymphotropic virus type III.

Acquired Immunodeficiency Syndrome↗

PubMed1983

Characteristics of the acquired immunodeficiency syndrome (AIDS) in Haiti.

To identify the characteristics of the acquired immunodeficiency syndrome (AIDS) as it occurs in Haiti, we studied 61 previously healthy Haitians who had diagnoses of either Kaposi's sarcoma (15), opportunistic infections (45), or both (1) established in Haiti between June 1979 and October 1982. The first cases of Kaposi's sarcoma and opportunistic infections in Haiti were recognized in 1978-1979, a period that coincides with the earliest reports of AIDS in the United States. We do not believe that AIDS existed in Haiti before this period. The types of opportunistic infections and the clinical course in Haitians with Kaposi's sarcoma and opportunistic infections were similar in most aspects to those in patients with AIDS in the United States. The median age of Haitians with Kaposi's sarcoma and opportunistic infections was 32 years, and 85 per cent were men. The interval between diagnosis and death was six months in 80 per cent of the patients. Diarrhea was the most common reason for seeking medical attention in patients with opportunistic infections. Lymphopenia and skin-test anergy were observed in 86 and 100 per cent of patients, respectively. Potential risk factors (bisexual activity or blood transfusions) were identified in 17 per cent of male and 22 per cent of female patients. Demographic information suggests that patients belonged to all socioeconomic strata of Haitian society.

Acquired Immunodeficiency Syndrome↗