Biomedical subjects

Catherine Belin

Publications and source records attributed to Catherine Belin.

4 recordsLinked to original sources

PubMed2006

[Pain and dementia].

Dementia and pain are both common in the elderly and then frequently associated. The literature review shows that pain in dementia is underdiagnosed and consequently undertreated. This can be linked to: 1) the difficulty of pain assessment in patients with cognitive disorders and altered communication skills; 2) changes of pain processing and especially in the motivational-affective domain; 3) modified efficacy of analgesic drugs. This has been documented in Alzheimer's disease but remains to be investigated in the other types of dementia in order that all patients can be treated whatever their diagnosis, illness duration and type of pain (acute versus chronic).

Aged↗

PubMed2004

Neglected attention in apparent spatial compression.

Halligan and Marshall [Cortex 27 (1991) 623] devised a new test to evaluate the hypothesis that in visual neglect, left space is systematically compressed rightwards. In the critical condition of the original study, rows of horizontally arranged numbers with a target arrow pointing to one of them from the opposite margin of the display were presented. When asked to verbally identify the number indicated by the arrow, a right brain-damaged patient with left neglect and hemianopia often indicated a number to the right of the target. The more the target was located on the left, the greater the response shift rightward, as if rightward compression were linearly proportional to the co-ordinates of Euclidian space. However, a possible alternative account could be that the patient's attention was attracted by the numbers located to the right of the target digit, thus biasing her responses toward numbers on the right. To explore this hypothesis, we asked normal participants and patients with right hemisphere lesions, with and without neglect or hemianopia, to mark on the margin of a sheet the approximate location indicated by an arrow situated on the opposite margin. In three different conditions, the arrow indicated either one of several numbers or lines in a row, or a blank location on the sheet margin. Only patients with left neglect, and especially those with associated hemianopia, deviated rightward, and then crucially only on those conditions where visible targets were present, consistent with the attentional bias account.

Adult↗

PubMed2004

Detection of 1st- and 2nd-order temporal-envelope cues in a patient with left superior cortical damage.

This psychophysical study explores the extent to which the auditory cortex is necessary for various aspects of temporal-envelope perception, that is, perception of the slow temporal modulations in amplitude known to be crucial for sound identification. The ability to detect 1st- and 2nd-order sinusoidal amplitude modulation (AM) is evaluated in a single patient showing left-hemisphere damage encroaching the primary and secondary auditory cortices. Here, 1st- and 2nd-order AM refer to (1) sinusoidal variation in the amplitude of a 2 kHz pure tone, and (2) sinusoidal variation in the depth of a 64 Hz AM applied to the 2 kHz pure tone, respectively. The results replicate previous findings by showing that damage to the left auditory cortex results in a selective deficit in auditory sensitivity to the lowest 1St-order AM (i.e., 1st-order AM frequencies < 16 Hz). Moreover, a dissociation is apparent between the ability to detect 1st- and 2nd-order temporal-envelope cues. The patient shows poorer than normal ability to detect 2nd-order AM at low frequencies ranging from 4-23 Hz, but normal ability to detect the high (64 Hz) 1st-order AM carrying these 2nd-order modulations. This result indicates that damage to the left primary and secondary auditory cortices affects the ability to detect temporal variations in the local properties of sounds(such as AM depth). It is also consistent with the idea that, as in vision, central nonlinear mechanisms are involved in the computation of such local (or 2nd-order) temporal properties.

Acoustic Stimulation↗

PubMedDate not supplied

Is the attentional blink effect located in short-term memory?

The attentional blink (AB) effect is characterized by a failure to detect a second target following the identification of a previous target in a RSVP stream. This effect has been attributed to capacity limitations at a central level of visual information processes. Postperceptual models suppose that the AB locus is located in short-term memory. To test this hypothesis, we investigated the influence of a short-term memory deficit on the AB effect in a patient with such a deficit. The three main results of this study are (1) the persistence of an AB effect, (2) a large number of T1 missed identifications and (3) a T2 detection deficit for a specific delay (367 ms). These results indicate that a short-term memory deficit disrupts the processing of each target (T1 and T2) but does not product an abolition of the AB effect.

Adult↗