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C Arroyo

Publications and source records attributed to C Arroyo.

26 records · Page 2Linked to original sources
PubMed1993

Selective attention and brainstem frequency-following responses.

In the auditory system, cortical event-related potential amplitudes are enhanced during selective attention within the auditory channel. In the case of brainstem responses, however, the results are less clear since only a few studies have reported attention effects. Nearly all of these studies have used click stimuli to elicit the brainstem auditory evoked response (BAER). In the present study, pure tones (200 and 400 Hz) elicited the brainstem frequency-following response (FFR) in a task that maximized channel separation by presenting different frequencies to each ear. Twelve male and 12 female subjects participated. Perceptual sensitivity (d') showed an overall right ear advantage (REA) that did not depend on gender or stimulus frequency. FFR averages were enhanced by digital filtering, the 25 ms response was partitioned in half, and quantified by fast-Fourier analysis. Results of the statistical analysis showed a significant Attention x Frequency x Half interaction. Thus, whether or not component amplitudes were larger during attention depended on the particular stimulus and temporal location within the FFR. These results are more complex and time variant than would be predicted by the hypothesis that attention only enhances evoked response amplitudes. Nevertheless, these results suggest that some form of attention-related modulation may be occurring at the level of the brainstem. The present results provide additional support for a peripheral gating mechanism in humans, which has been claimed in a minority of BAER studies. The FFR may provide additional useful information since it presumably depends on phase-locking neural elements, rather than on-units activated by acoustic transients.

Adult↗
PubMedDate not supplied

[Frequent users and difficult patients: how do they feel about their treatment by doctors?].

BACKGROUND: To determine the opinions and expectations of difficult, frequent user, patients about their relationship with their GP. MATERIAL AND METHODS: Qualitative design. Discussion groups. Invitation to a meeting at the Chantrea Health Centre (Pamplona). The participants were frequent users of the health centre in the year 2003, who had been defined as "difficult"--according to previously defined criteria--by each of the 12 doctors of the health centre. Excluded were patients with mental retardation, severe hearing problems, severe mental illness, difficulties in mobility and travelling, and over 70 years of age. Groups were formed from amongst the 112 preselected patients. Four groups were designed: "older" persons (GMA) of 46 to 70 years (14); "women" (GMU) of 31 to 45 years (14); "men" (GHO) of 31 to 45 years (13) and "youths" (GJO) of 16 to 30 years (12). The patients were invited by letter and by a subsequent telephone confirmation to a meeting, the content of which was not specified. Sessions of 2 hours duration were held with each of the groups formed. Audio recording, with prior authorization, and verbatim transcription of sessions. Discussion and content analysis by the research group resulting in lines of consensus. RESULTS: The three groups of older patients were formed with a total of 16 participants. The group of youths was not formed since the figure for attendance did not reach the number of 3 or more after three appointments. CONCLUSIONS: From the perspective of the patient it is very important that there should be efficient communication with the doctor. Awareness of a state of frequent use was not detected in those attending. They feel themselves to be chronic patients who need frequent attention. Satisfaction at the treatment received was observed as well as an understanding attitude towards the organisational limitations of the health centre. They did not give verbal expression to the existence of conflictive relations with their GPs.

Adolescent↗