Measures Of Visual Memory Research Articles

Presymptomatic hippocampal atrophy in Alzheimer's disease. A longitudinal MRI study.

The hippocampal formation (HF) is known from pathological and MRI studies to be severely atrophied in established Alzheimer's disease. However, it is unclear when the earliest changes in the HF occur. We performed a longitudinal study of asymptomatic individuals at risk of autosomal dominant familial Alzheimer's disease in order to assess presymptomatic changes in the HF. Seven at risk members of a familial Alzheimer's disease pedigree associated with the amyloid precursor protein 717 valine to glycine mutation underwent serial MR scanning and neuropsychological assessments over 3 years. These assessments were compared with results from 38 normal controls. During the study three at risk subjects became clinically affected. Volumetric measurement of the HF showed that asymmetrical atrophy developed in these subjects before the appearance of symptoms. Verbal and visual memory measures declined in parallel with hippocampal loss. A loss of up to 8% per annum of the volume of the HF occurred in the 2 years over which symptoms first appeared. These findings may have implications for early diagnosis of Alzheimer's disease.

Construct validity of the continuous visual memory test

The construct validity of the Continuous Visual Memory Test (CVMT), a new measure of visual recognition memory was evaluated based on the performance of 92 healthy, normal adults. A series of factor analyses were conducted utilizing marker variables for verbal memory, visual memory, attention and concentration, and verbal and visual/nonverbal intellectual functions. CVMT acquisition scores were associated with verbal and visual/nonverbal intellectual factors as well as with attentional ability. The CVMT delayed recognition score was shown to be a factorially “pure” measure of visual memory.

Effects of age on the Rey-Osterrieth and Taylor complex figures: test-retest data using an intentional learning paradigm.

The degree to which the Rey-Osterrieth and Taylor complex figures provide equivalent measures of visual memory, and the effects of age on figure comparability were examined in two experiments. Both experiments employed a multiple-trial, intentional learning procedure wherein each figure was administered twice in a counterbalanced sequence to subjects aged 20 to 80 years. In Experiment 1, a constant 60-s exposure duration was used; in Experiment 2, a self-pacing procedure was employed where the exposure duration was individually determined. The results from both experiments showed that the Taylor figure was easier to learn than the Rey-Osterrieth figure, indicating that the two figures are not equivalent for testing memory. These results were supported by subjective judgements on the relative difficulty to learn and remember each figure. Finally, younger (20-59 years) subjects performed at a higher level than older (60-80 years) subjects on both figures. Recommendations and possible alternatives are suggested regarding the use of the figures in both constructional and visuo-spatial memory test-retest situations.

Clinical Utility of the Selective Reminding Test-Children's Version

The clinical utility of the Selective Reminding Test (SRT) children's version was examined in two studies. Study 1 investigated differences among children with learning disabilities (LD), seizure disorders (SD), and normal controls (NC). The results indicated overall significance among the groups; the NC subjects evidenced higher scores. Follow-up comparisons showed differences to be present for measures of initial memory encoding and consistent retrieval. Study 2 examined differences between children with adequate consistent long-term memory abilities (MA) and children with dysfunctional consistent long-term memory skills (MD). The groups were formulated based on performance on the Consistent Long Term Retrieval Scale from the SRT and were compared on other neuropsychological measures. The results indicated the MD children to be significantly below the MA children on measures of visual memory, abstraction ability, and mental flexibility. The results of both studies are discussed in relation to practical and theoretical relevance.

Construct validity of the continuous visual memory test

The construct validity of the Continuous Visual Memory Test (CVMT), a new measure of visual recognition memory was evaluated based on the performance of 92 healthy, normal adults. A series of factor analyses were conducted utilizing marker variables for verbal memory, visual memory, attention and concentration, and verbal and visual/nonverbal intellectual functions. CVMT acquisition scores were associated with verbal and visual/nonverbal intellectual factors as well as with attentional ability. The CVMT delayed recognition score was shown to be a factorially "pure" measure of visual memory.

The search for a “pure” visual memory test: Pursuit of perfection?

Abstract Factor analyses of clinical memory tests have demonstrated that scores on tests purported to measure “visual memory” load highly on visuoperceptual and visuoconstructional factors with modest loadings on measures that define general learning and memory. This may reflect the multifactorial nature of visual-spatial memory and a multitude of methodological and test construction issues. This paper is intended to provide the clinical neuropsychologist with an explanation as to why the search for a pure measure of visual memory has been an arduous one and identifies five reasons for this apparent difficulty. Suggested directions for future nonverbal memory test development are offered.

Prenatal exposure to cannabis: A preliminary report of postnatal consequences in school-age children

Aspects of neurobehavioural development were examined in 28 school-age children born to regular cannabis users and 28 control children matched on prenatal drug history. Measures which discriminated between the study groups and on which the children of cannabis users scored more poorly included parental ratings of behaviour problems, visual-perceptual tasks, language comprehension, and distractibility. For a measure of visual memory and a measure of language comprehension, mother's age at the child's birth potentiated the effect of cannabis use to produce lowered scores for children of young, cannabis-using mothers relative to children of young, nonusing mothers. After controlling for the influence of mother's age at delivery, mother's personality and home environment, the relationship between prenatal cannabis exposure and the discriminating variables was no longer statistically significant. Path analysis demonstrated the way in which home environment conditions, particularly high levels of aggression, could magnify effects of prenatal exposure to cannabis on postnatal outcomes.

Construct validity of various memory testing procedures.

The construct validity of Wechsler Memory Scale Logical Memory, Paired Associate Learning and Visual Reproduction subtests was evaluated, as well as the validity of the Benton Visual Retention Test, and the two memory factor scales of the Luria-Nebraska Neuropsychological Battery (LNNB). The results of a series of factor analyses based on test performances of 102 subjects indicated that delayed reproduction measures of visual memory were more valid than the traditional immediate reproduction administrations, which were more closely associated with visual-perceptual-motor abilities. Construct validity was also demonstrated for Logical Memory and Paired Associate Learning. Although both LNNB measures loaded on a memory factor, item heterogeneity and brief sampling of items raised serious questions about the clinical utility of these scales.

Factor analysis of the WAIS and Wechsler Memory Scale: an analysis of the construct validity of the Wechsler Memory Scale.

The WAIS and Wechsler Memory Scale subtest scores of 256 neurologic and nonneurologic subjects were factor analyzed. The results supported the construct validity of the Wechsler Memory Scale as a measure of verbal learning and memory, attention and concentration, and orientation. Construct validity was not demonstrated for the Visual Reproduction subtest as a measure of visual memory. Suggestions are offered for future development and research on measures of visual memory.

A measure of short-term visual memory based on the WISC-R coding subtest.

Adapted the Coding subtest of the WISC-R to provide a measure of visual memory. Three hundred and five children, aged 8 through 12, were administered the Coding test using standard directions. A few seconds after completion the key was taken away, and each was given a paper with only the digits and asked to write the appropriate matching symbol below each. This was termed "Coding Recall." To provide validity data, a subgroup of 50 Ss also was administered the Attention Span for Letters subtest from the Detroit Tests of Learning Aptitude (as a test of visual memory for sequences of letters) and a Bender Gestalt recall test (as a measure of visual memory for geometric forms). Coding Recall means and standard deviations are reported separately by sex and age level. Implications for clinicans are discussed. Reservations about clinical use of the data are given in view of the possible lack of representativeness of the sample used and the limited reliability and validity of Coding Recall.

Computerized Assessment of Memory Performance in Dementia

Memory deficits in demented patients were studied by applying a computerized system to titrate individual memory performance. Two delayed matching to sample tasks were used. ABA1 involved random visual shapes used as a measure of visual memory. ABA2 involved nonsense syllable trigrams used as a measure of verbal memory. A Human Test System panel with a display screen was utilized. This screen was a rear view projection window divided into four independent 3 X 2 sections arranged in a 2 X 2 matrix. The sample stimulus appeared on the upper left window for one second. The delay interval between stimulus sample and choices varied by 7 seconds dependent upon patient performance per trial. Also utilized was a color distractor task. Task parameters, data acquisition, retrieval, and graphic print-outs were all computerized. Individual titration levels reflected the severity of neurological impairment. Computerized assessment enabled subtle changes in memory performance to be readily identified. Implications for use of the system as a screening device in the assessment of mental changes in the elderly are apparent.