Biomedical subjects

Hadyn D Ellis

Publications and source records attributed to Hadyn D Ellis.

7 recordsLinked to original sources

PubMed2006

Diagnosing delusions: a review of inter-rater reliability.

Although several studies have examined the reliability of diagnosing delusions there is no comprehensive review of the literature. Therefore, the reliability of diagnosing 'delusions in general' and the subcategory of 'bizarre delusions' was reviewed, including both structured interview and standardized instrument methods. The literature suggests that delusions in general can be diagnosed reliably with both structured interview and standardized instruments. However, bizarre delusions are not reliably diagnosed by either, suggesting that this concept may have little clinical validity. Nevertheless, many of the studies reviewed are poorly designed or subject to significant confounds. Criteria are suggested for adequate future studies.

Delusions↗

PubMed2006

Delusions: A suitable case for imaging?

This review is intended to outline the need/opportunities for imaging research in the area of delusions. In particular, delusions of misidentification are offered as possible examples of how both spatial and temporal brain imaging may throw light upon the theoretical, parallel processes of identification and emotional arousal occurring when a familiar face is encountered. Other types of Delusional Misidentifications are also briefly explored. The review then turns to related phenomena, including the ways imaging may help elucidate different types of covert face recognition; and also further explain the distinctive (but not entirely independent) processes underlying face, voice and object recognition. Throughout the review the aim is to emphasise the potential value to cognitive neuropsychiatry of good imaging techniques.

Brain↗

PubMed2006

Explaining delusions: a cognitive perspective.

There is now considerable evidence for reasoning, attention, metacognition and attribution biases in delusional patients. Recently, these findings have been incorporated into a number of cognitive models that aim to explain delusion formation, maintenance and content. Although delusions are commonly conceptualized as beliefs, not all models make reference to models of normal belief formation. This review considers those models that explain delusions as a breakdown of normal belief formation (belief-positive models), approaches that explain the pathology only (belief-negative models) and approaches that view delusions as one end of a distribution of anomalous mental phenomena (the continuum view). A cognitive theory that includes the 'pragmatic pathology' of delusions will be able to address both the phenomenology and the treatment of delusion-related distress.

Attention↗

PubMed2005

The Cardiff Anomalous Perceptions Scale (CAPS): a new validated measure of anomalous perceptual experience.

The study describes the Cardiff Anomalous Perceptions Scale (CAPS), a new validated measure of perceptual anomalies. The 32-item CAPS measure is a reliable, self-report scale, which uses neutral language, demonstrates high content validity, and includes subscales that measure distress, intrusiveness, and frequency of anomalous experience. The CAPS was completed by a general population sample of 336 participants and 20 psychotic inpatients. Approximately 11% of the general population sample scored above the mean of the psychotic patient sample, although, as a group, psychotic inpatients scored significantly more than the general population on all CAPS subscales. A principal components analysis of the general population data revealed 3 components: "clinical psychosis" (largely Schneiderian first-rank symptoms), "temporal lobe disturbance" (largely related to temporal lobe epilepsy and related seizure-like disturbances) and "chemosensation" (largely olfactory and gustatory experiences), suggesting that there are multiple contributory factors underlying anomalous perceptual experience and the "psychosis continuum."

Adolescent↗

PubMed2005

'Internet delusions': a case series and theoretical integration.

BACKGROUND: Delusions involving the internet have been reported as examples of the influence of cultural innovations on delusion formation, although there has been some debate as to whether such innovations simply affect surface content, or whether they have more substantial clinical or psychopathological implications. SAMPLING AND METHODS: Four cases of patients with delusions involving the internet were identified following a general request to local consultant psychiatrists for referrals. RESULTS: The internet had a specific effect on aetiology in one case, and knowledge of the internet seemed to constrain the type of delusion formed in two others. The presence of an internet-related delusion in the final case was used to frame a successful clinical intervention based on the 'collaborative empiricism' method, using cognitive behavioural therapy and collaborative use of the internet to resolve the delusional belief. CONCLUSIONS: Cultural technical innovations may have specific influences on the form, origin and content of delusional beliefs. For some patients the presence of internet-themed delusions may be a good prognostic indicator since, given the rich sources of information available, they may be well suited to treatment with cognitive behavioural therapy.

Adult↗

PubMed2002

Asperger syndrome: tests of right hemisphere functioning and interhemispheric communication.

The primary aim of this investigation was to assess to what extent Rourke's (1989, 1995) nonverbal learning disabilities syndrome (NLD) model resembles the pattern of assets and deficits seen in people with Asperger syndrome (AS). NLD can be characterized by a cluster of deficits primarily affecting nonverbal aspects of functioning, in the presence of proficiency in single word reading and a superior verbal memory. The neurological underpinnings of this syndrome may be dysfunction of white matter affecting right hemisphere functioning and interhemispheric communication. To explore this hypothesis, eight participants with AS (ages 10 to 41 years) were assessed in the following areas: the pragmatics of language and communication, verbal and visual memory, visual-spatial abilities, and bimanual motor skills. Results confirmed the close similarity in the neuropsychologic profiles of NLD and AS.

Adolescent↗

PubMed2002

Exploring a neural-network account of age-of-acquisition effects using repetition priming of faces.

The question of whether age-of-acquisition (AoA), frequency, and repetition priming effects occur at a common stage or at different stages of processing is addressed. Two single-stage accounts (i.e., cumulative frequency and a neural-network simulation) are considered in regard to their predictions concerning the interactions between AoA and frequency with aging and priming effects. A repetition-priming face-classification task was conducted on both older and younger participants to test these predictions. Consistent with the predictions of the neural-network simulation, AoA had an effect on reaction times that could not be explained by cumulative frequency alone. Also, as predicted by the simulation, the size of the priming effect was determined by the cumulative frequency of the item. It is discussed how this evidence is supportive of the notion that AoA , frequency, and priming all have effects at a common and single stage during face processing.

Adolescent↗