Biomedical subjects

Paul Maruff

Publications and source records attributed to Paul Maruff.

60 records · Page 4Linked to original sources

PubMed2002

The neurobehavioural effects of kava.

OBJECTIVE: This review considers the context in which kava is used, together with its underlying psychopharmacological mechanisms, to investigate the neurobehavioural effects associated with kava use. METHOD: We conducted a systematic search using the computerized databases MEDLINE, OVID and PsychLIT for all articles containing any of the following words: kava, kavain, kawa and Piper methysticum. In the opinion of the authors, all articles from this collection containing data that could inform the neurological and cognitive sequelae of kava use were included for the purpose of this review. RESULTS: The use of kava occurs among indigenous populations in the South Pacific and in northern Australia, while also being used throughout the western world as a herbal medicine. Animal studies show that kava lactones alter neuronal excitation through direct interactions with voltage-dependent ion channels, giving rise to kava's muscle relaxant, anaesthetic, anxiolytic and anticonvulsive properties. Several isolated cases of psychotic and severe dystonic reactions following kava use suggest that kava also has psychoactive properties, yet there is no conclusive evidence that kava interferes with normal cognitive processes. CONCLUSIONS: Kava is effective in the treatment of tension and anxiety. There may be risk-factors for severe motor and psychiatric responses to kava use, although these are not well-understood. Given the increasingly widespread use of kava, further investigation is necessary to gain an understanding of its immediate neuropsychiatric effects and long-term cognitive effects.

Adult↗

PubMed2002

Behavioral characterization of mild cognitive impairment.

Results from recent investigations of behavioral and genetic outcomes in older people with mild cognitive impairment (MCI) have been inconsistent. These conflicting results may be attributed to between-study differences in the diagnostic systems employed, as well as the use of unreliable neuropsychological measures. We investigated behavioral and genetic outcomes in older people classified as having MCI according to novel criterion that required evidence of cognitive impairment on three consecutive neurological/neuropsychological assessments. One hundred and seventy four healthy older people were evaluated semi-annually for 12 months. Of these, 23 subjects were rated as having MCI on three consecutive assessments and were compared to 23 matched control subjects. Subjects rated as impaired on one or two of the three semi-annual assessments were also identified. MCI and matched control groups were compared on a range of behavioral measures. The prevalence of the Apolipoprotein E4 (ApoE4) allele was determined in all groups, and estimates of anxiety and depressive symptomatology were obtained. Subjective cognitive complaints were also assessed. Many subjects were classified as impaired on one or two assessments, however relatively few (n = 23) recorded consistent cognitive deficits. The most severe impairment observed in MCI subjects was on a test of pattern-location associative learning, however MCI subjects did not have insight into this impairment. The prevalence of the ApoE4 allele was not different between matched control and MCI groups. These results indicate that individuals with MCI can be differentiated from healthy older people and older people with transient cognitive impairments, but that such differentiation requires serial assessment of cognitive function.

Aged↗

PubMed2002

Anterior cingulate activation during Stroop task performance: a PET to MRI coregistration study of individual patients with schizophrenia.

OBJECTIVE: The authors used single-subject functional imaging analyses to 1) corroborate the findings of anterior cingulate hypoperfusion during an attentional task in schizophrenia and 2) examine whether anterior cingulate activation is associated with underlying morphology. METHOD: Five healthy subjects and six patients with schizophrenia underwent positron emission tomography scanning while they performed the Stroop task. The medial-frontal lobes were masked out for analysis, and activation peaks were individually coregistered to each subject's magnetic resonance imaging scan. RESULTS: Healthy subjects showed activations in both limbic and paralimbic anterior cingulate regions. Patients with schizophrenia showed only paralimbic activations, and these were apparent only in patients having a paracingulate sulcus. CONCLUSIONS: These findings suggest that 1) patients with schizophrenia have limbic-anterior cingulate hypoperfusion during attentional tasks and 2) paralimbic activation is associated with underlying morphology.

Adult↗

PubMed2002

Cognitive processing in children using cochlear implants: the relationship between visual memory, attention, and executive functions and developing language skills.

We performed this study to determine whether children using a cochlear implant performed differently from age- and gender-matched hearing aid users on 8 neuropsychological measures of visual memory, attention, and executive functioning. The study also examined whether differences in cognitive skills could account for some of the observed variance in speech perception, vocabulary, and language abilities of hearing-impaired children. In contrast to previous studies, our results revealed no significant cognitive differences between children who use a cochlear implant and children who use hearing aids. Partial correlation analysis indicated that the children's visual memory skills, ie, their recognition memory, delayed recall, and paired associative learning memory skills, correlated significantly with their language skills. When examined at a significance level of .01, attention and executive functioning skills did not relate to the children's developing speech perception, vocabulary, or language skills. The results suggested that differences in visual memory skills may account for some of the variance seen in the language abilities of children using implants and children using hearing aids.

Adolescent↗

PubMed2002

Motor imagery training ameliorates motor clumsiness in children.

Children with impaired motor coordination (or developmental coordination disorder) have difficulty representing internally the visuospatial coordinates of intended movements. We have proposed that this deficit reflects impairment in the generation of forward models of the efference copy of intended movements-the efference-copy-deficit hypothesis. In this study, we challenged this hypothesis by examining the efficacy of an imagery intervention designed specifically to train the forward modeling of purposive actions. A pre-post design was adopted. Fifty-four children referred with motor coordination problems were assigned randomly to one of three groups: imagery training, traditional perceptual-motor training, and wait-list control. The imagery protocol-delivered by an interactive CD-ROM-was shown to be equally effective to perceptual-motor training in facilitating the development of motor skill in the referred children. These results support the efference-copy-deficit hypothesis in explaining the cause of motor clumsiness in most children. Directions for future intervention studies and remediation in the field of developmental clumsiness are discussed.

Child↗

PubMedDate not supplied

Spatio-visual memory of children with specific language impairment: evidence for generalized processing problems.

BACKGROUND: Children with Specific language Impairment (SLI) have problems with verbal memory, particularly with tasks that have more processing demands. They also have slower speeds of responding for some tasks. AIMS: To identify the extent to which young children with SLI would differ in performance from age-matched non-impaired children on a set of spatio-visual memory tasks. It was predicted that if memory limitations of children with SLI extend beyond the verbal domain to other domains, their performance would be significantly poorer on the spatio-visual tasks than that of the comparison group. It was also predicted that they would be slower in responding. METHODS & PROCEDURES: Six spatio-visual tasks were used to compare the performance of 21 children with SLI, with a mean age of 54.1 months, and 21 age-matched non-impaired children. The tasks ranged in difficulty from simple recall to a search-based working memory task. All tasks were administered though a laptop computer and responses were non-verbal using a touch screen. OUTCOMES & RESULTS: The children with SLI were not significantly slower than the comparison group. However, they were significantly less accurate than the comparison group in recalling patterns, but not in recalling locations. The accuracy for both groups was lower on spatial recall than on pattern recall. The children with SLI were also significantly less able to learn to associate a particular pattern with a particular location, and to have a shorter spatial span. However, on a spatial search task testing working memory, the groups did not differ significantly. CONCLUSIONS: The results indicate that the memory limitations of children with SLI are not restricted to verbal memory, and this fact has implications for its aetiology. Intervention programmes for young children with SLI need to extend beyond language in order to help them develop strategies for processing information in different situations.

Association↗