The clinical utility of the Hopkins Verbal Learning Test as a screening test for mild dementia

Objective. The purpose of this study was to determine whether the Hopkins Verbal Learning Test (HVLT) could be used as a valid and reliable screening test for mild dementia in older people, and to compare its performance to that of the Mini-Mental State Examination (MMSE). Method. Using a cross-sectional design, we studied three groups of older subjects recruited from a district geriatric psychiatry service: (1) 26 patients with DSM-IV dementia and MMSE scores of 18 or better; (2) 15 patients with psychiatric diagnoses other than dementia; and (3) 15 normal controls. The relationship of each potential cutting point on the HVLT and the MMSE was examined against the independently ascertained DSM-IV diagnoses of dementia using a Receiver Operating Characteristic (ROC) analysis. Results. The subjects consisted of 21 (37.5%) males and 35 (62.5%) females with a mean age of 74.7 (SD 6.1) years and a mean of 8.5 (SD 1.8) years of formal education. ROC analysis indicated that the optimal cutting point for detecting mild dementia in this group of subjects using the HVLT was 18/19 (sensitivity = 0.96, specificity = 0.80) and using the MMSE was 25/26 (sensitivity = 0.88, specificity = 0.93). Conclusions. The HVLT can be recommended as a valid and reliable screening test for mild dementia and as an adjunct in the clinical assessment of older people. The HVLT had better sensitivity than the MMSE in detecting patients with mild dementia, whereas the MMSE had better specificity. Copyright (C) 2000 John Wiley & Sons, Ltd.

Test-retest reliability and practice effects of a rapid screen of mild traumatic brain injury

Test-retest reliabilities and practice affects of measures from the Rapid Screen of Concussion (RSC), in addition to the Digit Symbol Substitution Test (Digit Symbol), were examined. Twenty five male participants were tested three times; each testing session scheduled a week apart. The test-retest reliability estimates for most measures were reasonably good, ranging from .79 to .97. An exception was the delayed word recall test, which has had a reliability estimate of .66 for the first retest, and .59 for the second retest. Practice effects were evident from Times 1 to 2 on the sentence comprehension and delayed recall subtests of the RSC, Digit Symbol and a composite score. There was also a practice effect of the same magnitude found from Time 2 to Time 3 on Digit Symbol, delayed recall and the composite score. Statistics on measures for both the first and second retest intervals, with associated practice affects, are presented to enable the calculation of reliable change indices (RCI). The RCI may be used to assess any improvement in cognitive functioning after mild Traumatic Brain Injury.

The rapid screen of concussion: An evaluation of the non-word repetition test for use in mTBI research

Primary objectives: (1) To investigate the Nonword Repetition test (NWR) as an index of sub-vocal rehearsal deficits after mild traumatic brain injury (mTBI); (2) to assess the reliability, validity and sensitivity of the NWR; and (3) to compare the NWR to more sensitive tests of verbal memory. Research design: An independent groups design. Methods and procedures: Study 1 administered the NWR to 46 mTBI and 61 uninjured controls with the Rapid Screen of Concussion (RSC). Study 2 compared mTBI, orthopaedic and uninjured participants on the NWR and the Hopkins Verbal Learning Test (HVLT-R). Main outcomes and results: The NWR did not improve the diagnostic accuracy of the RSC. However, it is reliable and indexes sub-vocal rehearsal speed. These findings provide evidence that although the current form of the NWR lacks sensitivity to the impact of mTBI, the development of a more sensitive test of sub-vocal rehearsal deficits following mTBI is warranted.

Extended delayed recall of AVLT word lists: Effects of age and sex on adult performance

An extension of a previous study of age and sex effects on verbal recall (Geffen, Moar, O'Hanlon, lark, & Geffen, 1990) examined forgetting of words over extended delays. The AVLT was administered to 201 normal adults (99 males, 102 females) ranging in age between 20 and 59 years. Recall was tested at intervals of 30 minutes, 24 hours, and 7 days after acquisition. Testing of the latter two intervals was conducted by telephone (Experiment 1, N = 177). After 30 minutes there was no significant loss of the 10 to 11 words retained from five acquisition trials. However, an overall mean of about one word was forgotten after 1 day and a further word after 7 days. The oldest age group (50-59 years) acquired fewer words and forgot more words than the younger groups. Females of all age groups performed slightly better than males at acquisition, at retention, and at recall after longer delays. A second experiment showed that telephone testing at the longer delay intervals was equivalent to testing face to face. These results extend the use of the AVLT by assessing memory decay beyond the immediate testing period. Telephone follow-up is a convenient and economical method of testing delayed recall.

Verbal recall after mild traumatic brain injury: Sensitivity of the rapid screen of concussion

The present study aimed to determine whether including a sensitive test of immediate and delayed recall would improve the diagnostic validity of the Rapid Screen of Concussion (RSC) in mild Traumatic Brain Injury (mTBI) versus orthopaedic clinical samples. Two studies were undertaken. In Study 1, the performance of 156 mTBI and 145 orthopaedic participants was analysed to identify the number of individuals who performed at ceiling on the verbal memory subtest of the RSC, as this test required immediate and delayed recall of only five words. A second aim was to determine the sensitivity and specificity levels of the RSC. Study 2 aimed to examine whether replacement of the verbal memory subtest with the 12-word Hopkins Verbal Learning Test (HVLT) could improve the sensitivity of the RSC in a new sample of 26 mTBI and 30 orthopaedic participants. Both studies showed that orthopaedic participants outperformed mTBI participants on each of the selected measures. Study 1 showed that 14% of mTBI participants performed at ceiling on the immediate and 21.2% on delayed recall test. Performance on the original battery yielded a sensitivity of 82%, specificity of 80% and overall correct classification of 81.5% participants. In Study 2, inclusion of the HVLT improved sensitivity to a level of 88.5%, decreased specificity to a level of 70% and resulted in an overall classification rate of 80%. It was concluded that although inclusion of the five-word subtest in the RSC can successfully distinguish concussed from non-concussed individuals, use of the HVLT in this protocol yields a more sensitive measure of subtle cognitive deficits following mTBI.

Spatial learning ability of rats following differing levels of exposure to alcohol during early postnatal life

Rats exposed to a relatively high dose (7.5 g/kg body weight) of alcohol on either the fifth or tenth postnatal day of age have been reported to have long-lasting deficits in spatial learning ability as tested on the Morris water maze task. The question arises concerning the level of alcohol required to achieve this effect. Wistar rats were exposed to either 2, 4 or 6 g/kg body weight of ethanol administered as a 10% solution. This ethanol was given over an 8-h period on the fifth postnatal day of age by means of an intragastric cannula. Gastrostomy controls received a 5% sucrose solution substituted isocalorically for the ethanol. Another set of pups raised by their mother were used as suckle controls. All surgical procedures were carried out under halothane vapour anaesthesia. After the artificial feeding regimes all pups were returned to lactating dams and weaned at 21 days of age. The spatial learning ability of these rats was tested in the Morris water maze when they were between 61-64 days of age. This task requires the rats to swim in a pool containing water made opaque and locate and climb onto a submerged platform. The time taken to accomplish this is known as the escape latency. Each rat was subjected to 24 trials over 3 days of the test period. Statistical analysis of the escape latency data revealed that the rats given 6 g/kg body weight of ethanol had significant deficits in their spatial learning ability compared with their control groups. However, there was no significant difference in spatial learning ability for the rats given either 2 or 4 g/kg body weight of ethanol compared with their respective gastrostomy or suckle control animals. We concluded that ethanol exposure greater than 4 g/kg over an 8-h period to 5-day-old rats is required for them to develop long-term deficits in spatial learning behaviour. (C) 1998 Elsevier Science Inc.

Making distance learning E.R.O.T.I.C.: Applying interpretation principles to distance learning

Distance learners are self-directed learners traditionally taught via study books, collections of readings, and exercises to test understanding of learning packages. Despite advances in e-Learning environments and computer-based teaching interfaces, distance learners still lack opportunities to participate in exercises and debates available to classroom learners, particularly through non-text based learning techniques. Effective distance teaching requires flexible learning opportunities. Using arguments developed in interpretation literature, we argue that effective distance learning must also be Entertaining, Relevant, Organised, Thematic, Involving and Creative—E.R.O.T.I.C. (after Ham, 1992). We discuss an experiment undertaken with distance learners at The University of Queensland Gatton Campus, where we initiated an E.R.O.T.I.C. external teaching package aimed at engaging distance learners but using multimedia, including but not limited to text-based learning tools. Student responses to non-text media were positive.

Evaluative learning in human Pavlovian conditioning: Extinct, but still there?

Previous studies of human affective learning, the acquisition of likes and dislikes, provided evidence that extinction training does not affect changes in conditional stimulus (CS) valence as indexed by paper/pencil ratings. Experiment 1 (N = 32) investigated whether this is an artifact of the CS valence assessment, which is taken in test sessions before and after training. Pleasantness ratings were collected in pre/post training tests and, for half of the participants, on-line during training. Rated unpleasantness of the CS that preceded the aversive US (CS+) increased during acquisition and decreased during extinction back to neutral. However, as in previous studies, post extinction paper/pencil ratings revealed the maintenance of rated CS+ unpleasantness. Experiment 2 (N = 34) replicated this finding for two measures of CS valence, paper/pencil and the continuous measure used during training. The present results indicate that previous reports of failures to find extinction of affective learning may reflect renewal rather than maintenance of acquired CS valence across extinction training. (C) 2003 Elsevier Science (USA). All rights reserved.

Learning, odour preference and flower foraging in moths

Floral volatiles play a major role in plant-insect communication. We examined the influence of two volatiles, phenylacetaldehyde and a-pinene, on the innate and learnt foraging behaviour of the moth Helicoverpa armigera. In dual-choice wind tunnel tests, adult moths flew upwind towards both volatiles, with a preference for phenylacetaldehyde. When exposure to either of these volatiles was paired with a feeding stimulus (sucrose), all moths preferred the learnt odour in the preference test. This change in preference was not seen when moths were exposed to the odour without a feeding stimulus. The learnt preference for the odour was reduced when moths were left unfed for 24 h before the preference test. We tested whether moths could discriminate between flowers that differed in a single volatile component. Moths were trained to feed on flowers that were odour-enhanced using either phenylacetaldehyde or a-pinene. Choice tests were then carried out in an outdoor flight cage, using flowers enhanced with either volatile. Moths showed a significant preference for the flower type on which they were trained. Moths that were conditioned on flowers that were not odour-enhanced showed no preference for either of the odour-enhanced flower types. The results imply that moths may be discriminating among odour profiles of individual flowers from the same species. We discuss this behaviour within the context of nectar foraging in moths and odour signalling by flowering plants.

The concurrent validity and test-retest reliability of a visuospatial working memory task

To determine whether the visuospatial n-back working memory task is a reliable and valid measure of cognitive processes believed to underlie intelligence, this study compared the reaction times and accuracy of perforniance of 70 participants, with performance on the Multidimensional Aptitude Battery (MAB). Testing was conducted over two sessions separated by 1 week. Participants completed the MAB during the second test session. Moderate testretest reliability for percentage accuracy scores was found across the four levels of the n-back task, whilst reaction times were highly reliable. Furthermore, participants' performance on the MAB was negatively correlated with accuracy of performance at the easier levels of the n-back task and positively correlated with accuracy of performance at the harder task levels. These findings confirm previous research examining the cognitive basis of intelligence, and suggest that intelligence is the product of faster speed of information processing, as well as superior working memory capacity. (C) 2004 Elsevier Inc. All rights reserved.

Transient prenatal vitamin D deficiency is associated with subtle alterations in learning and memory functions in adult rats

Based on clues from epidemiology, low prenatal vitamin D has been proposed as a candidate risk factor for schizophrenia. Recent animal experiments have demonstrated that transient prenatal vitamin D deficiency is associated with persistent alterations in brain morphology and neurotrophin expression. In order to explore the utility of the vitamin D animal model of schizophrenia, we examined different types of learning and memory in adult rats exposed to transient prenatal vitamin D deficiency. Compared to control animals, the prenatally deplete animals had a significant impairment of latent inhibition, a feature often associated with schizophrenia. In addition, the deplete group was (a) significantly impaired on hole board habituation and (b) significantly better at maintaining previously learnt rules of brightness discrimination in a Y-chamber. In contrast, the prenatally deplete animals showed no impairment on the spatial learning task in the radial maze, nor on two-way active avoidance learning in the shuttle-box. The results indicate that transient prenatal vitamin D depletion in the rat is associated with subtle and discrete alterations in learning and memory. The behavioural phenotype associated with this animal model may provide insights into the neurobiological correlates of the cognitive impairments of schizophrenia. (c) 2005 Elsevier B.V. All rights reserved.

Impaired memory and olfactory performance in NaSi-1 sulphate transporter deficient mice

In the present study, NaSi-l sulphate transporter knock-out (Nas1-/-) mice, an animal model of hyposulphataernia, were examined for spatial memory and learning in a Morris water maze, and for olfactory function in a cookie test. The Nas1-/- mice displayed significantly (P < 0.05) increased latencies to find an escape platform in the reversal teaming trials at 2 days but not 1 day after the last acquisition trial in a Morris water maze test. suggesting that Nas1-/- mice may have proactive memory interference. While the wild-type (Ncis1+/+) mice showed a significant (P < 0.02) decrease in time to locate a hidden food reward over four trials after overnight fasting, Nas1-/- mice did not change their performance, resulting in significantly (P < 0.05) higher latencies when compared to their Nas1+/+ littermates. There were no significant differences between Nas1-/- and Nas1+/+ mice in the cookie test after moderate food deprivation. In addition, both Nas1-/- and Nas1+/+ mice displayed similar escape latencies in the acquisition phase of the Morris water maze test, suggesting that learning, motivation, vision and motor skills required for the task may not be affected in Nas1-/- mice. This is the first study to demonstrate an impairment in memory and olfactory performance in the hyposulphataemic Nas1-/- mouse. (c) 2004 Elsevier B.V. All rights reserved.