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R J Ivnik

Publications and source records attributed to R J Ivnik.

11 recordsLinked to original sources
PubMed1992

Validity of the construct of nonverbal memory: a factor-analytic study in a normal elderly sample.

One problem in evaluating the construct of nonverbal memory is finding a purely nonverbal memory measure. Encouraged by initial research with a new measure, the Visual Spatial Learning Test (VSLT), we examined nonverbal memory in a normal elderly sample. Subjects were 460 community-dwelling individuals between the ages of 55-95. All received neuropsychological batteries which included the Wechsler Adult Intelligence Scale-Revised, the Wechsler Memory Scale-Revised, the Rey Auditory Verbal Learning Test, and the VSLT. Two variable sets were created to avoid overlapping immediate and delayed recall trials for the same stimulus materials. Exploratory factor analyses using two different extraction methods were performed. Across analyses a single general memory factor was observed, no modality or time specific factors were found. If it can be assumed that we used adequate measures of nonverbal memory, our results combine with prior research to challenge the validity of the construct of nonverbal memory as distinct from verbal memory, especially in older normal adult populations.

Aged↗
PubMed1992

Memory function in normal aging.

We evaluated memory function in a group of 161 community-dwelling, cognitively normal individuals aged 62 to 100 years recruited as part of the Mayo Clinic Alzheimer's Disease Patient Registry. We used the Free and Cued Selective Reminding Test and the Rey Auditory Verbal Learning Test to evaluate two aspects of memory function thought to be sensitive to the effects of aging: learning (acquisition) and delayed recall (forgetting). The results were quite consistent and demonstrated that learning or acquisition performance declines uniformly with increasing age but is not related to education. Delayed recall or forgetting, however, remained relatively stable across age when adjusted for the amount of material initially learned. These findings are relevant for assessing normal memory function relative to the early impairments found in dementia and form a baseline against which memory performance can be assessed by the clinician. In particular, suspicion regarding a disorder of brain function affecting memory processes should be raised if learning performance declines more rapidly than expected or if delayed recall is impaired to any significant extent.

Aged↗
PubMed1991

Associative anomia: dissociating words and their definitions.

A 60-year-old woman, in whom magnetic resonance imaging and single photon emission computed tomography confirmed the presence of chronic damage to the left temporal lobe, had pure anomia with sparing of other language and cognitive functions. She could independently access lexical knowledge (words) and semantic knowledge (word definitions). We postulate that her anomia was due to a failure to associate lexical and semantic knowledge.

Anomia↗
PubMed1991

Age-associated memory impairment diagnoses: problems of reliability and concerns for terminology.

Objective memory criteria for diagnosing age-associated memory impairment (AAMI), age-consistent memory impairment, and late-life forgetfulness (LLF) were applied to 523 cognitively normal older persons divided into 2 groups on the basis of the clinical memory assessment battery they received. Seventy-seven percent of Group 2 and 98% of Group 1 met the Crook et al. (1986) cognitive criteria for AAMI on at least 1 test. Rates based on individual tests varied from 7% to 96%. Objective-cognitive criteria for LLF were met by no members of Group 1 but by 31% of Group 2. Results suggest that, as proposed, the criteria for age-related diagnoses lack reliability. Concerns regarding the diagnosis of normal memory in older populations are considered.

Aged↗
PubMed1989

Selective posterior cerebral artery injection of amytal: new method of preoperative memory testing.

The carotid Amytal test (Wada test) was introduced, in 1948 by Wada, to localize speech function before temporal lobectomy in patients with medically refractory epilepsy, and it remains the standard for that purpose. The same test has also been used since 1962 to evaluate memory function; however, the adequacy of the test in this application has been viewed with increasing skepticism in recent years. Therefore, we developed an alternative to the Wada test. It consists of selective injection of Amytal into the posterior cerebral artery (PCA). This PCA Amytal test is designed to test only memory function (not language). We present several anatomic and functional reasons why this approach should be superior to the Wada test for this purpose. We also present preliminary data in support of this hypothesis. To date, we have had successful results of the PCA Amytal test in 38 of 45 patients (84%), and one major complication has occurred (2%).

Adolescent↗
PubMed1988

Anterior temporal lobectomy for the control of partial complex seizures: information for counseling patients.

We examined the effect of anterior temporal lobectomy on cognitive function in the treatment of intractable partial complex seizures in a sample of 142 patients. Our current results replicate previous work in this area and clearly establish the presence of differential effects on cognitive function as a consequence of the side of the operation. Learning and memory are most susceptible to impairment postoperatively, although general intellectual abilities are also affected in a small number of patients. The data are further analyzed in a manner that permits determination of the probability of cognitive alterations postoperatively for individual patients. Information is provided to assist health-care professionals in evaluating the risk-to-benefit ratio relative to cognitive abilities as they consider this treatment alternative for their patients who suffer from intractable partial complex seizures.

Adult↗
PubMed1987

Effects of anterior temporal lobectomy on cognitive function.

Sixty-three patients with intractable partial complex epilepsy were treated by anterior temporal lobectomy for seizure control. Psychometric studies before and after operation documented cognitive function and evaluated the effects of operation on cognition. The mean follow-up period was 7.7 months. Sixty-two of 63 patients had improved seizure control; 49 (78%) were seizure free. Operation had different effects on cognitive abilities in those with right vs. left temporal lobe excisions. Although both groups maintained summary IQ scores in the average range, after operation the left temporal group was less efficient on language-dependent cognitive tasks, particularly those that involved complex learning and memory. In contrast, persons who had right temporal ablations were either unchanged or slightly better cognitively after operation. Future research and clinical evaluations should focus on the components of the learning and memory processes when the ramifications of temporal lobe ablations on cognitive function are studied.

Adult↗
PubMed1978

Neuropsychological test performance as a function of the duration of MS-related symptomatology.

Thirty-six patients with definite diagnoses of multiple sclerosis received an extensive battery of neuropsychological tests. The MS patients were grouped in triads, and the members of each triad were matched on the basis of their sex, age at time of experiencing their first MS-related symptom, and education. One member of each triad was assigned to each of three experimental groups on the basis of the number of years they had complained of MS-related symptoms (i.e., one to five, six to ten, or greater than ten years). Data analyses yielded a limited number of significant findings. Differences on measures of verbal intelligence and reading skills were suggested as more probably reflecting a tendency for the "older" MS patients to have had more formal education, than being a true consequence of the disease process. Only a measure of simple tactile perception skills significantly delineated the experimental groups in a manner consistent with clinical observation of MS deterioration.

Adolescent↗