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Biomedical subjects

C Lundeen

Publications and source records attributed to C Lundeen.

7 recordsLinked to original sources
PubMed1993

Characteristics of colon cancer at time of presentation.

OBJECTIVE: To evaluate the relationships between demographic and clinical characteristics and the stage and site of colon cancer at the time of presentation. METHODS: New cases of colon cancer identified through a tumor registry at a teaching hospital during 1989 were reviewed retrospectively. Of the 110 cases, 53% of the subjects were female, 95% were white, and 63% were more than 70 years of age. RESULTS: Early stages of colon cancer (Dukes A [11%] or B [41%]) occurred in 52%, and late stages (Dukes C [26%] or D [22%]) in 48%. Most patients (88%) presented with symptoms; 12% of the cases were detected in asymptomatic patients. Of the 13 asymptomatic patients, 7 were identified by positive occult blood in the stool, 5 by colonoscopy, and 1 during a hysterectomy. The stage of colon cancer was more likely to be early in asymptomatic patients (85% Dukes A or B) compared to those with symptoms (47% Dukes A or B) (p < 0.02). Sixty-two percent (62%) of the cecum/ascending colon cancer were early compared to 46% of the cancers in other locations (p = 0.11). Seventy-seven percent (77%) of the asymptomatic cancers were located in the cecum/ascending colon compared to 33% of the symptomatic patients (p < 0.02). Age and gender were not associated with site or stage of colon cancer. CONCLUSION: The majority of patients with colon cancer are diagnosed when symptomatic. When colon cancer is diagnosed while still asymptomatic, it is more likely to be at an early stage. The most common screening procedure leading to diagnosis in asymptomatic patients is the identification of fecal occult blood. Colon cancer is more likely to be located in the cecum/ascending colon when diagnosed at an asymptomatic stage.

Aged↗
PubMed1989

Factors affecting workers' compensation claims activity.

This study examined whether and to what degree workers' compensation claims activity is related to the regulatory environment, prevalence of occupational injury, and employment conditions. A major finding was that when economic conditions induce people to leave the work force, a related increase in workers' compensation claims tends to occur. This statistically significant relationship was evident in both the recent history of workers' compensation awards for occupational hearing loss in West Virginia and in federal workers' compensation claims activity during the 1970s.

West Virginia↗
PubMed1987

Effect of warble-tone frequency deviation on threshold measurement in cases with sloping audiometric configurations.

A 2.1-kc/s pure-tone (p-t) mask at 80 db SPL created for 7 normal-hearing young adults a hearing threshold configuration which sloped sharply in the 2-kc/s frequency region. Conventional masked audiometry at 1, 1.5, and 2 kc/s was performed with pure tones and with tones sinusoidally modulated at 20 c/s by +/- 5, 10, and 20%. In frequency regions where the masked audiogram was relatively flat, p-t and warble-tone (w-t) HTLs were equivalent. However, at 2 kc/s, w-t HTLs were substantially better (as much as 32 db) than p-t HTLs. The w-t vs p-t discrepancy increased with frequency deviation from 5-20%, attributable to the spread of modulated signal energy into frequency regions where hearing sensitivity was better than at the nominal test frequency. Clinicians should be alert to the possibility that testing with warbled tones may underestimate the amount of hearing loss for pure tones in those with sloping audiometric configurations.

Acoustic Stimulation↗
PubMed1986

The prevention of noise-induced hearing loss in the school-aged population: a school educational hearing conservation program.

A questionnaire assessing knowledge of hearing and hearing loss, and planned hearing conservation practices, was collected from 71 high school students before and after an educational hearing conservation program (HCP) consisting of a film, a lecture and a handout. An average increase of 16.7% correct responses from pre- to postexposure to the HCP was found. Moreover, substantial percentages of respondents stated that they now plan to use hearing protection devices and procedures, when appropriate, and about 80% stated they found the HCP helpful to them.

Adolescent↗
PubMed1984

The influence of temporal cues on the strength of periodicity pitches.

Three different waveforms were generated from the same component frequencies by setting the phase of the components so they were either homophasic (all component sinusoids start at 0 degree), diphasic (sinusoids alternate between -45 degrees and + 45 degrees), or heterophasic (starting phase randomly selected). Listeners were asked to rate the saliency of all periodicity pitches they could detect in stimuli which contained 12 or more components at frequencies above the region where pitches were perceived . A major finding was that the highest ratings of fundamental frequency (f1) pitch "strength" were always obtained for homophasic waveforms, which among the test stimuli have the most abrupt envelope fluctuations. In contrast, diphasic and heterophasic waveforms, which have smoother envelopes, yielded lower pitch strength estimates at f1 and higher ratings two octaves above the fundamental. These data indicate that information concerning the stimulus waveform envelope influences the relative prominence of competing pitches evoked by periodicity pitch stimuli. However, no one-to-one correspondence between pitch and waveform periodicity is apparent.

Acoustic Stimulation↗
PubMed1980

Detection of signals with identical energy spectra but different waveforms under conditions of signal uncertainty.

Previous research has shown that a signal which may be one of two pure tones will be less detectable than a signal that is of constant, known frequency. In the present study, the effect of waveform uncertainty was evaluated by using pulse-train signals with identical power spectra but different phase spectra. Results for a group of 11 listeners suggest that when differences in the energy spectra of signals are eliminated, signal uncertainty has, at best, a small effect on detection performance.

Acoustic Stimulation↗