Tom N. Tombaugh

The Mini‐Mental State Examination: A Comprehensive Review

The purpose of this paper is to provide a comprehensive review of information accumulated over the past 26 years regarding the psychometric properties and utility of the Mini‐Mental State Examination (MMSE).

Trail Making Test A and B: Normative data stratified by age and education

Normative data for the Trail Making Test (TMT) A and B are presented for 911 community-dwelling individuals aged 18-89 years. Performance on the TMT decreased with increasing age and lower levels of education. Based on these results, the norms were stratified for both age (11 groups) and education (2 levels). The current norms represent a more comprehensive set of norms than previously available and will increase the ability of neuropsychologists to determine more precisely the degree to which scores on the TMT reflect impaired performance for varying ages and education.

The Test of Memory Malingering (TOMM): Normative data from cognitively intact and cognitively impaired individuals.

Four experiments were undertaken to validate the Test of Memory Malingering (TOMM). In the first 3 experiments, the TOMM was administered to 475 community-dwelling individuals and 161 neurologically impaired patients (traumatic brain injury, aphasia, cognitive impairment, and dementia). Both clinica

Five Validation Experiments of the Test of Memory Malingering (TOMM).

The Test of Memory Malingering (TOMM; T. N. Tombaugh, 1996) is a newly developed visual recognition test that uses pictures of common objects as stimuli. Prior normative research with community-dwelling adults and neurologically impaired patients has shown that the TOMM possesses a high degree of specificity and is not affected by demographic variables such as age and education. The current series of 5 integrated experiments was designed to provide important validation data. Converging evidence from all studies showed that scores on the TOMM are able to detect when an individual is not putting forth maximum effort. Overall, the TOMMs high levels of sensitivity and specificity suggest that it has high promise as a clinical test for detecting malingering of memory impairments.

Effects of dopamine receptor blockade on alimentary behaviors: Home cage food consumption, magazine training, operant acquisition, and performance

Administration of the dopamine receptor blocker pimozide (1.0 mg/kg) disrupted the initiation, but not the maintenance, of home cage food consumption. Likewise, the number of pellets consumed during magazine training was decreased among pimozide-treated rats during the first, but not the second day of training. The acquisition of a bar-press response for food reinforcement (using a retractable bar) was severely retarded by pimozide. However, such an impairment was not evident if animals initially received 2 training days in the absence of the drug. Further, among rats trained to bar press to asymptote using a nonretractable bar, pimozide reduced the within and between days bar-press rate such that performance was indistinguishable from that of animals placed on extinction in the absence of the drug treatment. When transferred from the pimozide treatment to extinction in the absence of drug, the response rate increased to the level observed during the first session of either extinction or pimozide in the continuous reinforcement condition. The results are discussed in terms of sensory-motor and reinforcement consequences of dopamine receptor blockade.

Extinction and dopamine receptor blockade after intermittent reinforcement training: Failure to observe functional equivalence

Response decrements in an operant task produced by either extinction or by the dopamine receptor blocker pimozide were examined in three experiments which employed intermittent reinforcement schedules. In contrast to the congruency between these treatments previously observed following continuous reinforcement training, treatment with pimozide was markedly more effective than extinction in decreasing performance after training with variable interval, fixed interval, and fixed ratio reinforcement. The two treatments also produced substantially different patterns of responding. A shift from extinction to pimozide did not alter the progressive decline in response rate over days, but a shift from pimozide to extinction caused a pronounced increase of performance. These results indicate that the pimozide and extinction treatment did not produce functionally equivalent effects, and that the role of dopamine on reward processes should not be inferred from comparisons between pimozide and extinction.

The 60-item Boston Naming Test: norms for cognitively intact adults aged 25 to 88 years.

Age- and education-stratified norms on the 60-item Boston Naming Test (BNT) are presented for 219 cognitively intact adults aged 25-88 years. The sample size, age range, and education levels of this sample represent an improvement over currently available norms. Eight short forms of the BNT are compared with the 60-item BNT. Frequency of errors for individual BNT items and the distribution of incorrect responses over seven different categories of errors are discussed. Finally, specific probes to overcome difficulties with ambiguous items are suggested.

Effects of pimozide on nondiscriminated and discriminated performance in the pigeon

The effects of pimozide (0.06, 0.18, 0.30 mg/kg), a dopamine receptor blocker, on nondiscriminated and discriminated performance were assessed in pigeons using a Latin Square design. In Experiment 1 a dose-dependent decrease in responding was observed with a variable interval 3-min schedule of reinforcement. More detailed analyses showed that total response rate, running respose rate, and post-reinforcement pause all showed the same dosedependent relationship. In Experiment 2 a successive discrimination task was employed to determine if pimozide affects a previously learned association between environmental stimuli. Each pigeon was first trained on the discrimination and then injected with the same doses as in Experiment 1. Although pimozide reduced responding in a dose-related fashion, a corresponding decrease in accuracy of responding was not evident. It was concluded that pimozide has a general response debilitating effect and that dopaminergic neurons probably are not involved in subserving associative processes.

Effects of pimozide on accuracy of performance and distribution of correct responding on a simultaneous discrimination task in the rat

After training rats in a simultaneous discrimination problem, pimozide, a dopamine receptor blocker, was administered to determine whether accuracy of performance would be disrupted. Each animal received five doses of pimozide (vehicle, 0.05, 0.10, 0.30, and 0.60 mg/kg) delivered in a Latin Square sequence with five non-drug days between injections. Pimozide did not disrupt well established discrimination behavior at any of the doses even though a decrease in rate of responding was observed at the two higher doses. These results provide additional evidence that DA neutrons are not essential in the mediation of previously learned associations.

Failure to obtain functional equivalence between dopamine receptor blockade and extinction: Evidence supporting a sensory-motor conditioning hypothesis

The effects of pimozide were tested in a discrete trial paradigm. Following 8 days of continuous reinforcement training with a retractable bar, subjects were divided into 3 groups: Vehicle-Extinction; Pimozide-Extinction and Pimozide-Reinforcement. Pimozide rats received 1 mg/kg of drug 4 hours prior to test. On each of 3 test days reinforcement continued to be delivered on a continuous reinforcement schedule for the Pimozide-Reinforcement Group whereas it was no longer delivered for the other two groups. Each test day was separated by 4 drug-free days. The Pimozide-Reinforcement Group showed the least response suppression, followed by the Vehicle-Extinction and Pimozide-Extinction Groups. These results do not support the anhedonic hypothesis that dopamine containing neurons mediate reward processes and were interpreted within a sensory-motor conditioning framework.