The factor structure of the Quality of Life Inventory (QOLI) following traumatic brain injury.

Quality of life is a key indicator of outcome following traumatic brain injury (TBI). Research has reported several different factor structures for the Quality of Life Inventory (QOLI, Frisch, 1994). We compared the fit of existing factor models and examined the clinical utility of the QOLI's factors in a sample of Australian adults with TBI. Archival data from 901 participants were provided by the Neurotrauma Register of Tasmania. Participants were aged 16-80 years and 63% were male. Approximately 69% had mild TBI (PTA < 24 h), approximately 24% had moderate TBI (PTA >1 day, <7 days) and 7% had severe TBI. Both cross sectional and longitudinal analyses were utilized, as participants provided data at one or more of seven time-points, up to 3 years following injury. The results showed the data best fitted a three-factor model, comprising Self-functioning and activity, Self-actualization and Family and environment factors, and a second order Overall QOL factor. Differences in the trajectory of recovery were noted between the QOLI factor scores over time and in relation to demographic and injury variables. In conclusion, the three-factor structure of the QOLI provided useful clinical information about the recovery of patients' subjective quality of life following TBI.

Native American mitochondrial DNA analysis indicates that the Amerind and the Nadene populations were founded by two independent migrations.

Mitochondrial DNAs (mtDNAs) from 167 American Indians including 87 Amerind-speakers (Amerinds) and 80 Nadene-speakers (Nadene) were surveyed for sequence variation by detailed restriction analysis. All Native American mtDNAs clustered into one of four distinct lineages, defined by the restriction site variants: HincII site loss at np 13,259, AluI site loss at np 5,176, 9-base pair (9-bp) COII-tRNA(Lys) intergenic deletion and HaeIII site gain at np 663. The HincII np 13,259 and AluI np 5,176 lineages were observed exclusively in Amerinds and were shared by all such tribal groups analyzed, thus demonstrating that North, Central and South American Amerinds originated from a common ancestral genetic stock. The 9-bp deletion and HaeIII np 663 lineages were found in both the Amerinds and Nadene but the Nadene HaeIII np 663 lineage had a unique sublineage defined by an RsaI site loss at np 16,329. The amount of sequence variation accumulated in the Amerind HincII np 13,259 and AluI np 5,176 lineages and that in the Amerind portion of the HaeIII np 663 lineage all gave divergence times in the order of 20,000 years before present. The divergence time for the Nadene portion of the HaeIII np 663 lineage was about 6,000-10,000 years. Hence, the ancestral Nadene migrated from Asia independently and considerably more recently than the progenitors of the Amerinds. The divergence times of both the Amerind and Nadene branches of the COII-tRNA(Lys) deletion lineage were intermediate between the Amerind and Nadene specific lineages, raising the possibility of a third source of mtDNA in American Indians.

Processing of timbre and rhythm in musicians and non-musicians.

Expert musicians and non-musicians of similar educational and social class background were compared in two experiments involving perception of timbre and rhythm. In Experiment 1 where dichotic monitoring for the sound of the violin was required, there was a practice effect but no ear or group differences. The rhythm monitoring experiment produced a group by ear interaction with musicians faster on the right ear than the left and faster than non-musicians on the right ear only. Analysis of strategies reported by subjects showed that verbal labelling did not apparently influence laterality. Lack of evidence for individual laterality effects reinforces the claim that with stringent experimental and subject controls there is minimal evidence for musicians non-musician laterality effects.

The lateralization of arithmetic and number processing: a review.

Calculation and number processing require ideographic and semantic operations which may involve the right as well as the left hemisphere. There is often also present a spatial component, whether overt as with column-addition or multiplication procedures, or covert if numbers are recoded into continuously varying analog quantities or magnitudes of a psychophysical or imaginal nature, to facilitate numerical comparison. Again right hemisphere mechanisms may be partly responsible. Evidence for such a minor hemisphere contribution is reviewed in the light of studies with clinical and commissurotomy cases, and normal subjects. Calculation itself is hard to define, as it often seems to reduce to the operation of overlearn, associative, tabular look-up functions and algorithms. Indeed alphabetic comparisons analogous to numerical tasks should generate similar laterality effects in clinical and normal populations.