Verbal Memory Abilities of Children With Brain Tumors

Several critical neuroanatomical structures and pathways for memory performance are located in the third ventricle region. This led us to predict that verbal memory abilities would be more impaired in children treated for third ventricle tumors compared to those treated for cerebellar tumors. Archival data was obtained from 24 pediatric patients with third ventricle region tumors and 18 pediatric patients with cerebellar tumors. Neuroradiological verifications of tumor involvement and hydrocephalus severity (i.e., Evans Index) on preoperative scans and MRIs proximal to the time of the neuropsychological evaluation were conducted. The potential confounds of hydrocephalus severity, seizure medication, age, radiation treatment, and chemotherapy were addressed. Verbal IQ was comparable between tumor groups and in the Average range. The third ventricle region group performed significantly worse on list learning and delayed list recall compared to the cerebellar group. Their mean performance was in the clinically impaired range on both trials. The third ventricle region tumor group performed better than the cerebellar tumor group on Digit Span, a basic repetition, attention span task. These findings support the hypothesis that pediatric patients with third ventricle region brain tumors are more likely to be impaired on verbal recall tasks compared to pediatric patients with cerebellar brain tumors. In contrast, patients who were treated for cerebellar tumors were more impaired on the basic repetition, attention span task compared to patients who were treated for third ventricle tumors. Future studies should examine the specific neuroanatomical structures and pathways that are damaged and may influence differential cognitive impairments in children.     

Attention and Memory in Children with Brain Tumors

The Rey Auditory Verbal Learning Test was utilized to examine attention, learning, and memory abilities in 42 children with cerebellar (N?=?18) and third ventricle tumors (N?=?24). Children with cerebellar tumors exhibited significant auditory attentional impairments and displayed adequate encoding and retrieval across subsequent learning and memory trials. In contrast, children with third ventricle tumors exhibited average auditory attentional abilities, but they displayed mild encoding deficits across trials 2–5. Furthermore, the third ventricle group's compromised performance on the delayed recall trial and average performance on the delayed recognition trial is suggestive of underlying retrieval deficits.     

Attention and memory in children with brain tumors.

The Rey Auditory Verbal Learning Test was utilized to examine attention, learning, and memory abilities in 42 children with cerebellar (N = 18) and third ventricle tumors (N = 24). Children with cerebellar tumors exhibited significant auditory attentional impairments and displayed adequate encoding and retrieval across subsequent learning and memory trials. In contrast, children with third ventricle tumors exhibited average auditory attentional abilities, but they displayed mild encoding deficits across trials 2-5. Furthermore, the third ventricle group's compromised performance on the delayed recall trial and average performance on the delayed recognition trial is suggestive of underlying retrieval deficits.     

Executive dysfunction affects word list recall performance: Evidence from amyotrophic lateral sclerosis and other neurodegenerative diseases

The Rey Auditory Verbal Learning Test (RAVLT) is widely used in clinical practice to evaluate verbal episodic memory. While there is evidence that RAVLT performance can be influenced by executive dysfunction, the way executive disorders affect the serial position curve (SPC) has not been yet explored. To this aim, we analysed immediate and delayed recall performances of 13 non‐demented amyotrophic lateral sclerosis (ALS) patients with a specific mild executive dysfunction (ALSci) and compared their performances to those of 48 healthy controls (HC) and 13 cognitively normal patients with ALS. Moreover, to control for the impact of a severe dysexecutive syndrome and a genuine episodic memory deficit on the SPC, we enrolled 15 patients with a diagnosis of behavioural variant of frontotemporal dementia (bvFTD) and 18 patients with probable Alzheimer's disease (AD). Results documented that, compared to cognitively normal subjects, ALSci patients had a selective mid‐list impairment for immediate recall scores. The bvFTD group obtained low performances with a selectively increased forgetting rate for terminal items, whereas the AD group showed a disproportionately large memory loss on the primary and middle part of the SPC for immediate recall scores and were severely impaired in the delayed recall trial. These results suggested that subtle executive dysfunctions might influence the recall of mid‐list items, possibly reflecting deficiency in control strategies at retrieval of word lists, whereas severer dysexecutive syndrome might also affect the recall of terminal items possibly due to attention deficit or retroactive interference.     

Exploring the characteristics of the visuospatial hebb repetition effect

Using the dot task (see Jones, Farrand, Stuart, & Morris, 1995)--regarded as a good visuospatial analogue of the verbal serial recall task--we examined whether the Hebb repetition effect and its characteristics can be extended to visuospatial material. Classically, the Hebb effect has been associated with serial verbal memory: Repetition of a to-be-remembered sequence of verbal items every third trial markedly improves serial recall of that sequence. In the present study, Hebb effects were observed with visuospatial information, and a direct comparison between verbal and spatialsequence learning revealed that the Hebb repetition effect for visuospatial information shares similar characteristics with its verbal analogue. Our results cast some doubt regarding the parsimony of the view that the classical verbal Hebb effect is driven by a store specialized for phonological information and impose some further constraints on modeling serial memory and implicit sequence learning.     

Do alcoholic amnesic patients passively rehearse verbal information?

Recently it has been claimed that alcoholic amnesic patients mainly engage in passive repetitive rehearsal during spontaneous learning and that this contributes to their memory problem. To test this hypothesis further, two experiments were conducted which compared list learning in amnesic patients and normal controls. In Experiment I both groups of subjects were required either to learn a list which was presented five times consecutively with free recall following each presentation, or they were asked to repeat each word out loud as they saw it and carry on doing so until the next word was shown. Five presentation trials were given and free recall was again tested after each presentation. It was predicted that if the amnesics' spontaneous form of learning involved only passive repetition there should be no difference between learning and repetition for this group while the controls should show an impairment in repeating compared to learning. The results showed that both groups of subjects were impaired to the same extent with repeating compared to learning and it was concluded that spontaneous learning was similar in both groups and that neither group merely passively rehearsed during spontaneous learning. A second experiment examined recognition performance of the two groups of subjects after learning or repeating lists of 20 words. Recognition was tested with distractors which were irrelevant, acoustically similar, graphemically similar, or semantically similar to the target word. It was found there were no differences between either of the groups in the pattern of errors made over the different distractor types. It was thus concluded that there was no encoding or rehearsal abnormality in the amnesic group. The possibility of differences between groups of alcoholic amnesics was discussed as well as the putative role of slow cognitive processing in their memory problems.     

Aging and memory for words and action events: effects of item repetition and list length

We were concerned with the effects of item repetition, list length, and class of item on free recall in elderly as compared with young adults. In Experiment 1, samples of young and elderly adults recalled a list of 27 words and a list of 27 action events (minitasks performed by the subjects). Some items were presented once and some twice. Although the younger subjects showed better recall on both types of lists, the older sample benefited from item repetition as much as did the younger sample. This finding was replicated in Experiment 2. A second finding in Experiment 2 was a significant aging effect in the recall of long but not of short lists of both words and action events. The absence of an Age X Repetition Effect interaction was ascribed to the strength nature of the repetition manipulation. The age effects in the recall of the long lists were attributed to possible deficits in retrieval proficiency.     

Efficacy of the keyword mnemonic method in adults

Two experiments were used to assess the efficacy of the keyword mnemonic method in adults. In Experiment 1, immediate and delayed recall (at a one-day interval) were assessed by comparing the results obtained by a group of adults using the keyword mnemonic method in contrast to a group using the repetition method. The mean age of the sample under study was 59.35 years. Subjects were required to learn a list of 16 words translated from Latin into Spanish. Participants who used keyword mnemonics that had been devised by other experimental participants of the same characteristics, obtained significantly higher immediate and delayed recall scores than participants in the repetition method. In Experiment 2, other participants had to learn a list of 24 Latin words translated into Spanish by using the keyword mnemonic method reinforced with pictures. Immediate and delayed recall were significantly greater in the keyword mnemonic method group than in the repetition method group.     

Language disorders in dementia of the Alzheimer type

The language profile of a group of 18 Alzheimer patients is documented and their performance on a standard aphasia test battery compared to a group of institutionalized, nonneurologically impaired control subjects matched for age, sex, and educational level. The Alzheimer patients scored significantly lower than the controls in the areas of verbal expression, auditory comprehension, repetition, reading, and writing. Articulation abilities were the same in each group. A language deficit was evident in all Alzheimer patients. The language disorder exhibited resembled a transcortical sensory aphasia. Syntax and phonology remained relatively intact but semantic abilities were impaired. The results support the inclusion of a language deficit as a diagnostic criterion of Alzheimer's disease.     

Memory for between‐list and within‐list information in amnesic patients with temporal lobe and diencephalic lesions

Patients with medial temporal lobe damage and diencephalic damage were compared on two tests of verbal temporal order memory: between‐list discrimination and within‐list discrimination. Both patient groups were impaired relative to a group of healthy control participants. In addition, despite comparable levels of item recognition, the diencephalic group was impaired relative to the medial temporal lobe group on both within‐list and between‐list discrimination. Temporal order memory for between‐list information showed a significant correlation with a composite measure of recognition memory, and the results are discussed in terms of the patients' reliance on familiarity and distance‐based processes to make temporal order judgments.     

Atypical memory performance in an autistic savant.

This study explored the mechanisms underlying the hypermnesia of an autistic savant (NM) through three experiments. The first two served to assess whether absence of interference was responsible for NM's exceptional list memory. The third investigated the type of cues used in recall. Results indicated absence of retroactive interference but presence of slight proactive interference in list recall of proper names. Normal interference effects were found, however, in list recall of common nouns. Exceptional performance was also demonstrated in a missing-name task involving spatial and verbal recall cues. The findings suggest that the outstanding episodic memory presented by some savant persons with autism might be related to an abnormally high resistance to interference.     

Recall of details never experienced: Effects of age,repetition, and semantic cues

To test theoretical predictions about the role of meaning connections in false memory, the effects of semantic cues and list repetition on children's false memories were evaluated across early childhood to mid-adolescence using the Deese–Roediger–McDermott (DRM) paradigm. True recall and false recall increased from 7 to 13 years. Study list repetition increased true recall of list words with the magnitude of this effect largest in the older children and adolescents. Repetition reduced false recall of critical lures in all age groups. Consistent with theoretical predictions, false recall of critical lures increased when children were informed of the thematic gist of each list prior to study.     

Tumor Locus Moderates Anxiety Symptoms in a Pediatric Neuro-Oncologic Sample

Despite the prevalence of pediatric Central Nervous System (CNS) solid tumors, little is understood about patients' disease-related anxiety experience. Data from 25 remitted pediatric CNS tumor patients posttreatment were collected. Significant symptoms of anxiety were reported by 32% of patients. MRI studies showed all anxious patients had right cortical tumors or left cerebellar tumors. Confound analyses suggest these results are not better accounted for by demographic, disease, or treatment variables. These results evidence the risk some pediatric neuro-oncologic patients face for developing significant anxiety symptoms.     

Atypical Memory Performance in an Autistic Savant

This study explored the mechanisms underlying the hypermnesia of an autistic savant (NM) through three experiments. The first two served to assess whether absence of interference was responsible for NM's exceptional list memory. The third investigated the type of cues used in recall. Results indicated absence of retroactive interference but presence of slight proactive interference in list recall of proper names. Normal interference effects were found, however, in list recall of common nouns. Exceptional performance was also demonstrated in a missingname task involving spatial and verbal recall cues. The findings suggest that the outstanding episodic memory presented by some savant persons with autism might be related to an abnormally high resistance to interference.     

Overt language production plays a key role in the Hebb repetition effect

When asked to recall verbatim a short list of items, performance is very limited. However, if the list of items is repeated across trials, recall performance improves. This phenomenon, known as the Hebb repetition effect (Hebb, 1961; Brain Mechanisms and Learning: A Symposium, pp. 37–51), is considered a laboratory analogue of language learning. In effect, learning a new word implies the maintenance of a series of smaller units, such as phonemes or syllables, in the correct order for a short amount of time before producing them. The sequence of smaller units is typically presented more than once. In the present study, we investigated the role of overt language production in language learning by manipulating recall direction. If the learning of a repeated list of items relies on overt language production processes, changing list production order by manipulating recall direction should impact the learning of the list. In Experiment 1, one list was repeated every third trial, and recall direction of the repeated list changed on the ninth repetition. In Experiment 1a, the repeated list changed from a forward to a backward order recall, where participants had to recall the items in reverse presentation order. In Experiment 1b, the repeated list changed from a backward to a forward order recall. Results showed a cost in recall performance for the repeated list when recall direction switched from forward to backward recall, whereas it was unaffected by the change from backward to forward recall. In Experiment 2, we increased the number of trials before introducing the change from a backward to a forward order recall. Results showed a decrement in recall performance for the repeated list following the change in recall direction, suggesting that language production processes play a role in the Hebb repetition effect.     

The Effects of Self-generated Cues on Recall of the Paragraphs of a Text

A self-generated list of short indications of the paragraphs of a text was shown to subjects to facilitate the retrieval of the text's contents during recall. The results of Experiment 1 indicated that a substantial number of potentially accessible paragraphs failed to be retrieved under ordinary conditions of free recall. Access to some paragraphs appears to have been inhibited progressively by previous, more or less complete, retrieval of the contents of other paragraphs. In Experiment 2, repetition of recall provided access to a significant number of supplementary paragraphs. A significant number of paragraphs initially reproduced, however, was omitted during secondary recall. In both experiments, the completeness of recalled paragraphs was a negative function of their serial position of output. In Experiment 3, inspection of a self-generated list of short indications of paragraphs and experimenter-provided verbal embellishment of half of the paragraphs affected recall independently.     

Exploring the correlates of impaired non‐word repetition in Down syndrome

Non‐word repetition, in which participants hear and repeat unfamiliar verbal stimuli, is thought to provide a particularly sensitive measure of verbal short‐term memory capacity. However, performance on this task can also be constrained by hearing and speech production skills, and by an individuals' linguistic knowledge. This study examined real word and non‐word repetition in a sample of 18 children and adolescents with Down syndrome, and compared their performance to that of a control group of 18 typically developing children in order to determine the extent of any impairment in repetition performance in Down syndrome, and the correlates of performance in each group. Individuals with Down syndrome were impaired in repetition performance, although both groups showed similar benefits of linguistic knowledge on repetition accuracy. An analysis of the correlates of non‐word repetition revealed a double dissociation between the patterns of associations seen in the two groups. Among typically developing individuals, non‐word repetition was related to an independent measure of verbal short‐term memory but not to vocabulary knowledge. However, among individuals with Down syndrome, performance was related to vocabulary knowledge but not verbal short‐term memory span. This contrast is consistent with the view that impairment to verbal short‐term memory prevents this system from fully supporting non‐word repetition in Down syndrome.     

The role of overt language production in the Hebb repetition effect

The Hebb repetition effect (Hebb, 1961) occurs when recall performance improves for a list that is repeated during a serial-recall task. This effect is considered a good experimental analogue to language learning. Our objective was to evaluate the role of overt language production in language learning by manipulating recall direction during a Hebb repetition paradigm. In each trial, seven nonsense syllables were presented auditorily. Participants had to orally recall the items either in the presentation order or in reverse order. One sequence was repeated every third trial. In Experiment 1, we compared learning from a group that had recalled the items in their presentation order to learning from a group that had recalled the items in the reverse order. The two groups yielded similar learning rates. In Experiment 2, recall direction was varied between trials. The learning rate was not affected when recall direction varied between trials, suggesting a limited role of overt language production in language learning.     

ASYMMETRY IN MOUTH OPENING DURING DIFFERENT SPEECH TASKS

When a normal subject is speaking, the right side of the mouth typically opens more widely or moves over a greater total distance. This asymmetry is most consistent during purely verbal word list generation and verbal recall tasks, less consistent when emotional expression and/or visual imagery is involved, and reversed during smiling. Aphasic patients also show the right bias during word lists, repetition, and conversation, but not during serial speech, singing and smiling. Since observable mouth asymmetry is presumed to result from hemispheric asymmetry in motor control, these observations confirm the major role of a left hemisphere control system for pure verbal expression and provide evidence for involvement of the right hemisphere in mouth motor control during emotional and prosodic expression or visual imagery. Therapeutic possibilities are also suggested.