Prevalence of stimulant use for attentional dysfunction in children with phenylketonuria

Recent data suggest that children with phenylketonuria (PKU) and poor metabolic control may have an increased prevalence of attentional dysfunction. However, few formal studies have addressed this topic in detail. We reviewed the medical records of 38 school-aged children with early and continuously treated PKU to determine the prevalence of stimulant use for attentional dysfunction, and to determine the relationship between metabolic control and attentional symptoms. Twenty-six per cent of the PKU children used a stimulant medication for attentional dysfunction. This is significantly higher than in an age- and sex-matched control group consisting of children with type I diabetes mellitus (6.5%, p <0.006), and also considerably higher than population norms for attention deficit hyperactivity disorder (ADHD) (5%). We also found a significant relationship between phenylalanine levels and stimulant use or attentional symptoms. Mean plasma phenylalanine concentration was 486 micromol/L in the non-stimulant-using group and 792 micromol/L in the stimulant-using group (p <0.02). Mean phenylalanine concentration was 462 micromol/L in the group not reporting attentional symptoms, and was 702 micromol/L in the symptomatic group (p <0.05). Parents of the stimulant-using children felt that the stimulants were efficacious in treating their child's attentional symptoms. Stimulant use and parent reports of attentional dysfunction are quite common in our PKU patients and appear to be strongly related to higher phenylalanine concentrations.

The relationship between depressive symptoms and cognitive dysfunction in multiple sclerosis

INTRODUCTION

Although it has been well established that otherwise healthy persons with depression experience various neuropsychological deficits, such a relationship has not been robustly supported in the initial investigations using the multiple sclerosis (MS) population. The relative inability to discover a significant relationship between depression and cognitive dysfunction may be due to methodological difficulties in previous studies (e.g., use of correlational analysis; use of neuropsychological measures that are generally not affected by depression).

METHODS

The present study examined a control group and 17 MS subjects who reported relatively low (BDI h 9) or high (BDI S 16) depression levels on a variety of neurocognitive measures that were (i.e., PASAT, Digit Span Backward subtest of the WAIS-R, and a modified version of the Buschke Selective Reminding Test; SRT) or were not (i.e., Similarities, Vocabulary, and Digit Span Forward subtests of the WAIS-R) hypothesised to be associated with depression symptomatology.

RESULTS

These results support our hypotheses that depressed individuals with MS evidence greater neuropsychological dysfunction relative to their nondepressed counterparts.

CONCLUSION

Findings are discussed in terms of the specific cognitive impairments evidenced by depressed subjects with MS. This research may have significant implications with regard to the expected effects of antidepressant and cognitive therapies on neuropsychological functioning in MS.

Differentiating simple versus complex processing speed: influence on new learning and memory performance

The current study was designed to examine how the construct of human information processing speed is conceptualized and measured, while also examining the influence of information processing speed on higher cognitive processes (i.e., learning). A mixed medical sample of 92 subjects participated in this study. Subjects underwent a broad-based neuropsychological evaluation, including measures of verbal and visuospatial new learning, spatial and verbal working memory, simple reaction time, choice reaction time, and information processing speed. Principal components factor analysis with varimax rotation resulted in a three-factor solution, comprised of: (1) simple speed/reaction time, (2) complex information processing and new learning, and (3) working memory. Notably, this factor solution identified 2 distinct forms of processing speed--simple and complex information processing speeds. In contrast to the abundance of literature grouping these two constructs together under one term (i.e., processing speed), these results indicate simple and complex speed to be distinct constructs assessed with different neuropsychological instruments. While the expected relationship between complex information processing capacities and working memory abilities was evident in this study, information processing speed also showed a significant relationship with new learning ability. The implications of this intriguing relationship are discussed.

Deciphering Components of Impaired Working Memory in Multiple Sclerosis

OBJECTIVE

To identify working memory (WM) impairment by examining components of auditory working memory with the same sample of individuals with multiple sclerosis (MS).

BACKGROUND

Although individuals with MS have consistently demonstrated WM impairments, the specific components involved (i.e., central executive versus storage/maintenance) remain unclear.

METHOD

Individuals with MS with and without cognitive impairment and healthy controls were administered a task primarily assessing storage and rehearsal/maintenance (auditory n-back) and a task with a significant central executive component (Paced Auditory Serial Addition Task).

RESULTS

Results indicate when the phonological loop is minimally challenged, maintenance of information is generally efficient. However, the addition of a central executive component to processing appears to be the key factor in differentiating individuals with MS with cognitive impairment from those without cognitive impairment and healthy controls.

CONCLUSIONS

Results indicated that the primary WM impairment in MS is within the central executive rather than the phonological loop.

Assessing the Behavioral Consequences of Multiple Sclerosis: An Application of the Frontal Systems Behavior Scale (FrSBe)

OBJECTIVE

The current study examines the utility of the Frontal Systems Behavior Scale (FrSBe) to document behavioral changes in people with multiple sclerosis (MS).

BACKGROUND

MS results in widespread central nervous system lesions that have a propensity for affecting frontal and parietal brain regions. As a result, behavioral symptoms may present, including disorders of executive functioning, apathy, and disinhibition.

METHOD

Twenty-six people with MS and 15 healthy controls (HC) underwent neuropsychological testing and completed the Frontal Systems Behavior Scale (FrSBe), and measures of emotional functioning.

RESULTS

Behavioral ratings for the MS group prior to illness were equivalent to those of the HC group. After illness however, a clinically and statistically significant increase was noted on two of three FrSBe scales, the apathy scale and the executive dysfunction scale. Relationships were also noted between the FrSBe family and self-report forms after illness and measures of neuropsychological performance, particularly information processing, working memory, and executive control. In contrast, physical disease progression was correlated with family ratings of behavior, but not self-ratings.

CONCLUSIONS

The FrSBe appears to be a sensitive measure of behavioral change in people with MS. Self-ratings and family ratings of behavioral changes are related to measures of neuropsychological performance. However, physical symptoms of MS are related only to the family ratings of behavior.

Can the repetition effect maximize learning in multiple sclerosis?

OBJECTIVE

The 'repetition effect' stipulates that recall ability improves as the number of learning trials that a person receives increases. While the repetition effect has been supported through many empirical investigations in healthy individuals, it has not yet been applied to clinical populations. The present study tested the hypothesis that an increased number of learning trials improves recall ability in persons with a neurological disorder, namely multiple sclerosis (MS).

DESIGN

Prospective between-group design with 30-minute, 90-minute and one-week assessments.

SETTING

Private, nonprofit, research facility.

SUBJECTS

Sixty-four MS subjects; 20 healthy control subjects (HC).

INTERVENTIONS

Subjects were given a modified Selective Reminding Test (SRT), a list of 10 words to remember in a selective reminding format. To control for the amount of information initially learned, the learning trials were repeated until the subject recalled all 10 words on two consecutive trials.

MAIN OUTCOME MEASURES

SRT word recall and recognition was tested 30 minutes, 90 minutes and one week subsequent to initial acquisition.

RESULTS

Interestingly, the antithesis of our hypothesis was found. That is, persons with MS who required more learning trials to reach the perfect learning criterion performed significantly worse on the recall trials. However, this was not the case in a sample of healthy individuals undergoing the same protocol.

CONCLUSIONS

These results indicate that individuals with MS may not benefit from repetition in isolation, but rather require the use of more intensive cognitive rehabilitation strategies (i.e., increased organization) to help improve their depth of encoding of new information.

Spacing of repetitions improves learning and memory after moderate and severe TBI

Extensive research has determined that new learning in healthy individuals is significantly improved when trials are distributed over time (spaced presentation) compared to consecutive learning trials (massed presentation). This phenomenon known as the "spacing effect" (SE) has been shown to enhance verbal and nonverbal learning in healthy adults of different ages and in different memory paradigms (e.g., recognition, recall, etc.). The purpose of this study was to examine whether learning in adults with moderate and severe traumatic brain injury (TBI) is improved using a spacing-of-repetitions procedure. Using a within-groups design, participants with TBI (n = 20) were presented a list of 115 words that were presented either once (single condition), twice consecutively (massed condition), or twice with 11 words between presentations (spaced condition). Participants were required to rank each word from 1 to 10 according to their familiarity with the word; they were not asked to "memorize" words for a later test. Word list learning was measured with a free recall test immediately following list presentation and with free recall and recognition tests after a 30-min delay. Participants recalled and recognized significantly more spaced words than massed words during this word list learning task. These results strongly indicate that the spacing of repetitions improves learning and memory in individuals who have sustained moderate to severe TBI. Implications for rehabilitation are discussed.

Functional magnetic resonance imaging technology and traumatic brain injury rehabilitation: guidelines for methodological and conceptual pitfalls

OBJECTIVES

To illuminate the current methodological and conceptual pitfalls inherent in conducting functional magnetic resonance imaging (fMRI) research with individuals who have sustained traumatic brain injury (TBI) and to discuss appropriate remedies. The aim is describe fMRI research, its limitations, and how to best use this technology to examine TBI.

DISCUSSION

The topics discussed in this article include issues regarding signal detection, brain activation measurement, head movement, and sources of signal artifact. Issues surrounding data interpretation and the importance of analyzing the brain as a connected neural network is also discussed. Finally, problems with spatial normalization when examining individuals with TBI are reviewed.

CONCLUSIONS

To date, there is a scarcity of research applying fMRI technology to the study of TBI. However, because it is a noninvasive procedure with high availability in hospital settings across the country, the next decade of TBI research will likely include a proliferation of this form of investigation. At this time, much work is needed to better understand how to optimally use this technology to examine the effects of TBI on behavior. For fMRI to enhance TBI research it will be imperative to establish valid research protocols and reliable methods of data interpretation.

Minimal neuropsychological assessment of MS patients: a consensus approach

Cognitive impairment is common in multiple sclerosis (MS), yet patients seen in MS clinics and neurologic practices are not routinely assessed neuropsychologically. In part, poor utilization of NP services may be attributed to a lack of consensus among neuropsychologists regarding the optimal approach for evaluating MS patients. An expert panel composed of neuropsychologists and psychologists from the United States, Canada, United Kingdom, and Australia was convened by the Consortium of MS Centers (CMSC) in April, 2001. Our objectives were to: (a) propose a minimal neuropsychological (NP) examination for clinical monitoring of MS patients and research, and (b) identify strategies for improving NP assessment of MS patients in the future. The panel reviewed pertinent literature on MS-related cognitive dysfunction, considered psychometric factors relevant to NP assessment, defined the purpose and optimal characteristics of a minimal NP examination in MS, and rated the psychometric and practical properties of 36 candidate NP measures based on available literature. A 90-minute NP battery, the Minimal Assessment of Cognitive Function in MS (MACFIMS), emerged from this discussion. The MACFIMS is composed of seven neuropsychological tests, covering five cognitive domains commonly impaired in MS (processing speed/working memory, learning and memory, executive function, visual-spatial processing, and word retrieval). It is supplemented by a measure of estimated premorbid cognitive ability. Recommendations for assessing other factors that may potentially confound interpretation of NP data (e.g., visual/sensory/motor impairment, fatigue, and depression) are offered, as well as strategies for improving NP assessment of MS patients in the future.

Telerehabilitation needs: a survey of persons with acquired brain injury

OBJECTIVE

To survey individuals with acquired brain injury to assess multiple facets of interest, access, and familiarity necessary to implement new telerehabilitation technologies.

DESIGN

Anonymous mail survey.

SETTING

Community.

PARTICIPANTS

Seventy-one respondents to a survey. These individuals had experienced acquired brain injury (predominantly severe traumatic brain injury [TBI]) and were living in the community. Surveys were mailed by a state chapter of the Brain Injury Association to a random selection of members with acquired brain injury.

MAIN OUTCOME MEASURE

Survey designed specifically for this investigation.

RESULTS

The survey responses indicate that there is great interest in the possibility of accessing telerehabilitative services among individuals with acquired brain injury. In particular, there was strong interest expressed in services that could be used to assist with problems in memory, attention, problem-solving, and activities of daily living.

CONCLUSIONS

Telemedicine, and more specifically telerehabilitation, holds great promise as an adjunct to traditional clinical service delivery. Little research in this area has been applied, however, to individuals with acquired brain injuries. Although on the surface, telerehabilitation seems to be an appropriate assessment and treatment modality for individuals with brain injury, it will only succeed if those individuals have the interest-and the access-necessary to use new and evolving technologies.

Dissociating basal forebrain and medial temporal amnesic syndromes: insights from classical conditioning

In humans, anterograde amnesia can result from damage to the medial temporal (MT) lobes (including hippocampus), as well as to other brain areas such as basal forebrain. Results from animal classical conditioning studies suggest that there may be qualitative differences in the memory impairment following MT vs. basal forebrain damage. Specifically, delay eyeblink conditioning is spared after MT damage in animals and humans, but impaired in animals with basal forebrain damage. Recently, we have likewise shown delay eyeblink conditioning impairment in humans with amnesia following anterior communicating artery (ACoA) aneurysm rupture, which damages the basal forebrain. Another associative learning task, a computer-based concurrent visual discrimination, also appears to be spared in MT amnesia while ACoA amnesics are slower to learn the discriminations. Conversely, animal and computational models suggest that, even though MT amnesics may learn quickly, they may learn qualitatively differently from controls, and these differences may result in impaired transfer when familiar information is presented in novel combinations. Our initial data suggests such a two-phase learning and transfer task may provide a double dissociation between MT amnesics (spared initial learning but impaired transfer) and ACoA amnesics (slow initial learning but spared transfer). Together, these emerging data suggest that there are subtle but dissociable differences in the amnesic syndrome following damage to the MT lobes vs. basal forebrain, and that these differences may be most visible in non-declarative tasks such as eyeblink classical conditioning and simple associative learning.

Driving behaviors following brain injury: self-report and motor vehicle records

BACKGROUND

This study examined both objective and subjective measures of driving behaviors occurring in the past 5 years for 47 individuals with traumatic brain injury (TBI) and 22 healthy controls (HC), matched for age, gender, education, and years of driving experience.

RESULTS

Overall, subtle descriptive differences in driving characteristics were observed between the two groups. However, comparison of self-reported and documented reports of aberrant driving behaviors did not reveal a significantly greater number of accidents or violations among TBI participants compared with HC drivers. The results suggest that individuals with TBI, who successfully complete a driving evaluation program, are able to reintegrate into the driving community with minimal difficulty.

Divided attention and driving: a pilot study using virtual reality technology

BACKGROUND

Virtual reality (VR) was used to investigate the influence of divided attention (simple versus complex) on driving performance (speed control).

DESIGN

Three individuals with traumatic brain injury (TBI) and three healthy controls (HC), matched for age, education, and gender, were examined.

RESULTS

Preliminary results revealed no differences on driving speed between TBI and HC. In contrast, TBI subjects demonstrated a greater number of errors on a secondary task performed while driving.

CONCLUSION

The findings suggest that VR may provide an innovative medium for direct evaluation of basic cognitive functions (ie, divided attention) and its impact on everyday tasks (ie, driving) not previously available through traditional neuropsychological measures.

Longitudinal assessment of neuropsychological functioning, psychiatric status, functional disability and employment status in chronic fatigue syndrome

The longitudinal course of subjective and objective neuropsychological functioning, psychological functioning, disability level, and employment status in chronic fatigue syndrome (CFS) was examined. The relations among several key outcomes at follow-up, as well as the baseline characteristics that predict change (e.g., improvement), were also evaluated. The study sample consisted of 35 individuals who met the 1988 and 1994 CFS case definition criteria of the Centers for Disease Control (CDC) at intake. Participants were evaluated a mean of 41.9 (SEM = 1.7) months following their initial visit (range = 24-63 months). Results indicated that objective and subjective attention abilities, mood, level of fatigue, and disability improve over time in individuals with CFS. Moreover, improvements in these areas were found to be interrelated at follow-up. Finally, psychiatric status, age, and between-test duration were significant predictors of outcome. Overall, the prognosis for CFS appears to be poor, as the majority of participants remained functionally impaired over time and were unemployed at follow-up, despite the noted improvements.

Quantitative assessment of cerebral ventricular volumes in chronic fatigue syndrome

Previous qualitative volumetric assessment of lateral ventricular enlargement in chronic fatigue syndrome (CFS) has provided evidence for subtle structural changes in the brains of some individuals with CFS. The aim of this pilot study was to determine whether a more sensitive quantitative assessment of the lateral ventricular system would support the previous qualitative findings. In this study, we compared the total lateral ventricular volume, as well as the right and left hemisphere subcomponents in 28 participants with CFS and 15 controls. Ventricular volumes in the CFS group were larger than in control groups, a difference that approached statistical significance. Group differences in ventricular asymmetry were not observed. The results of this study provide further evidence of subtle pathophysiological changes in the brains of participants with CFS.

Cardiovascular responses of women with chronic fatigue syndrome to stressful cognitive testing before and after strenuous exercise

OBJECTIVE

The purpose of this study was to compare the cardiovascular responses of patients with chronic fatigue syndrome (CFS) to healthy control subjects when performing stressful cognitive tasks before and after strenuous exercise.

METHOD

Beat-by-beat blood pressure and electrocardiogram were recorded on 19 women with CFS and 20 healthy nonexercising (ie, sedentary) women while they performed cognitive tests before, immediately after, and 24 hours after incremental exercise to exhaustion.

RESULTS

Diminished heart rate (p <.01) and systolic (p <.01) and diastolic (p <.01) blood pressure responses to stressful cognitive testing were seen in patients with CFS when compared with healthy, sedentary controls. This diminished stress response was seen consistently in patients with CFS across three separate cognitive testing sessions. Also, significant negative correlations between self-ratings of CFS symptom severity and cardiovascular responses were seen (r = -0.62, p <.01).

CONCLUSIONS

Women with CFS have a diminished cardiovascular response to cognitive stress; however, exercise did not magnify this effect. Also, the data showed that the patients with the lowest cardiovascular reactivity had the highest ratings of CFS symptom severity, which suggests that the individual response of the patient with CFS to stress plays a role in the common complaint of symptoms worsening after stress.

Functional magnetic resonance imaging of working memory impairment after traumatic brain injury

OBJECTIVES

To examine patterns of brain activation while performing a working memory task in persons with moderate to severe traumatic brain injury (TBI) and healthy controls. It is well established that working memory is an area of cognition that is especially vulnerable to disruption after TBI. Although much has been learned about the system of cerebral representation of working memory in healthy people, little is known about how this system is disrupted by TBI.

METHODS

Functional magnetic resonance imaging (fMRI) was used to assess brain activation during a working memory task (a modified version of the paced auditory serial addition test) in nine patients with TBI and seven healthy controls.

RESULTS

Patients with TBI were able to perform the task, but made significantly more errors than healthy controls. Cerebral activation in both groups was found in similar regions of the frontal, parietal, and temporal lobes, and resembled patterns of activation found in previous neuroimaging studies of working memory in healthy persons. However, compared with the healthy controls, the TBI group displayed a pattern of cerebral activation that was more regionally dispersed and more lateralised to the right hemisphere. Differences in lateralisation were particularly evident in the frontal lobes.

CONCLUSIONS

Impairment of working memory in TBI seems to be associated with alterations in functional cerebral activity.

Impaired delay eyeblink classical conditioning in individuals with anterograde amnesia resulting from anterior communicating artery aneurysm rupture

Anterior communicating artery (ACoA) aneurysm rupture can lead to an anterograde amnesia syndrome similar to that observed after damage to the hippocampus and medial temporal lobes (MT). It is currently believed that ACoA amnesia results from basal forebrain damage that disrupts hippocampal processing without direct hippocampal damage. Converging evidence from animal studies and computational modeling suggests that qualitative differences may exist in the pattern of memory impairment after basal forebrain or MT damage. For example, animals with basal forebrain but not hippocampal damage are impaired at delay eyeblink classical conditioning (EBCC). In this study, individuals with ACoA amnesia were shown to be impaired at delay EBCC compared with matched controls; this contrasts with the spared delay EBCC previously observed in MT amnesia. This finding suggests the beginning of a possible dissociation between the memory impairments in MT versus ACoA amnesia.

The influence of cognitive impairment on driving performance in multiple sclerosis

OBJECTIVE

To examine the influence of impaired cognitive processing on measures of driving skills in persons with MS.

METHODS

Twenty-eight subjects with documented MS were divided into two groups-with [MS(+), n = 13] and without [MS(-), n = 15] cognitive impairment-based on neuropsychological performance. Healthy control (HC) subjects (n = 17) matched on age and driving experience were also studied. Driving-related skills were compared between the groups based on performance on two computerized driving tests: the Useful Field of Vision (UFOV) and the Neurocognitive Driving Test (NDT).

RESULTS

The MS(+) group performed significantly worse than both the MS(-) and HC groups in the latency to perform several driving-specific functions on the NDT, but no overall group differences were observed in actual errors on the NDT. On the UFOV, when compared to MS(-) and HC subjects, the MS(+) group demonstrated poorer performance on two of the three subtests. Additionally, a significantly higher percentage of MS(+) individuals were rated within the high risk (probability of crash involvement) category, relative to the MS(-) and HC groups.

CONCLUSIONS

Cognitive impairment can negatively affect driving-related skills in persons with MS and should be considered in the determination of driving ability.

Functionally activated brain imaging (O-15 PET and fMRI) in the study of learning and memory after traumatic brain injury

Advances in functional imaging technology and cognitive neuropsychology have resulted in paradigms in which participants can perform cognitive tasks during functional image acquisition. We will discuss the application of two approaches (oxygen-15 positron emission tomography and functional magnetic resonance imaging) that have recently been used to examine components of learning and memory following traumatic brain injury (TBI). Activated functional brain imaging findings that we will discuss may suggest possible functional reallocation and reorganization of brain substrates involved in verbal learning and memory following brain injury. The findings also are clearly in line with other research that indicates a prominent role for the frontal lobes in learning and memory functioning, and support the concept of distributed neural networks for memory-related functions, cognitive load, and the potential for examining brain re-organization after injury.

Relationship of brain MRI abnormalities and physical functional status in chronic fatigue syndrome

Chronic Fatigue Syndrome (CFS) is an unexplained illness that is characterized by severe fatigue. Some have suggested that CFS is a "functional somatic syndrome" in which symptoms of fatigue are inappropriately attributed to a serious illness. However, brain magnetic resonance imaging (MRI) data suggest that there may be an organic abnormality associated with CFS. To understand further the significance of brain MRI abnormalities, we examined the relationship between MRI identified brain abnormalities and self-reported physical functional status in 48 subjects with CFS who underwent brain MR imaging and completed the Medical Outcomes Study SF-36. Brain MR images were examined for the presence of abnormalities based on 5 general categories previously shown to be sensitive to differentiating CFS patients from healthy controls. There were significant negative relationships between the presence of brain abnormalities and both the physical functioning (PF) (rho=-.31, p=.03), and physical component summary PCS (rho=-.32, p=.03) subscales of the SF-36. CFS patients with MRI identified brain abnormalities scored significantly lower on both PF (t(1,46) =2.3, p=.026) and the PCS (t(1,41) =2.4, p=.02) than CFS subjects without an identified brain abnormality. When adjusted for age differences only the PF analysis remained significant. However, the effect sizes for both analyses were large indicating meaningful differences in perceived functional status between the groups. These results demonstrate that the presence of brain abnormalities in CFS are significantly related to subjective reports of physical function and that CFS subjects with MRI brain abnormalities report being more physically impaired than those patients without brain abnormalities.

A comparison of memory performance in relapsing-remitting, primary progressive and secondary progressive, multiple sclerosis

OBJECTIVE

The current investigation was designed to examine the influence of disease course on the specific patterns of acquisition and retrieval impairments in multiple sclerosis (MS).

BACKGROUND

Recent investigations of learning and memory in MS have shown that many subjects have impaired verbal and visual new learning abilities, but normal long-term recall and recognition. However, heterogeneity in the learning and memory abilities of subjects has been documented. Some evidence in the literature suggests that this heterogeneity may be in part attributable to clinical variables, such as disease course.

METHODS

Verbal and visual learning and memory tests, modified to equate MS groups with healthy controls on initial acquisition of information, were administered to 64 individuals with clinically definite MS (relapse-remitting = 21; primary progressive = 18; secondary progressive = 25), and to 20 healthy control participants. Recall and recognition performance then was evaluated at 30 minutes, at 90 minutes, and at 1 week for the verbal learning task, and at 30 minutes and at 90 minutes for the visual learning task.

RESULTS

Results indicate that the two progressive forms of MS result in significantly greater deficits in regard to the acquisition of new verbal information, with the secondary progressive group showing a significantly higher failure rate in regard to meeting the learning criterion. Performance for recognition measures was not significantly different among groups, whereas recall performance of the primary progressive group was significantly below that of the control group and of the secondary progressive group. When testing new learning with visuospatial information, individuals with relapse-remitting MS and secondary progressive MS required more trials than control participants to learn the same amount of visual information. Visual recall and recognition performance did not differ between groups. No group differences in rates of forgetting for visuospatial material was observed after equating for acquisition.

CONCLUSIONS

Results of the current study indicate that the primary problem in MS with regard to memory functioning is in the acquisition of new information. Our findings support previous research showing verbal memory deficits with a progressive disease course and visuospatial memory deficits in relapse-remitting MS. However, the detailed analysis of new learning and memory performed in the current study indicated that the primary progressive group may be showing difficulty in their ability to use newly learned information. The pattern of new learning deficits observed between MS disease subtypes in the current study was determined to be unrelated to the duration of MS and to the physical severity of the disease. The degree of physical disability observed in patients with MS does not appear to be related to the degree of cognitive decline because of the distinct patterns and severity of memory dysfunction noted within each disease type, independent of physical disability.

Learning impairment is associated with recall ability in multiple sclerosis

Recent evidence suggests that persons with multiple sclerosis may experience deficits in verbal and visuospatial acquisition rather than recall. The present study was designed to determine whether this finding generalized to a broader range of neuropsychological tests of learning and memory. To control for group differences in information acquisition, healthy controls (HCs) and persons with multiple sclerosis (MS) were trained to specific learning criteria on both verbal (i.e., paragraph learning and paired associates) and visuospatial (i.e., facial recognition) memory tasks. Persons with MS required significantly more learning trials to meet criteria on the paragraph learning and facial recognition tasks, but not the paired associates test. However, after learning comparable amounts of information, the MS and HC groups recalled statistically similar amounts of information at 30-minutes, 90-minutes, and up to 1-week on the paragraph learning and paired associate tests. This suggests that persons with MS may have deficits in acquisition rather than recall per se. Results are discussed in terms of possible rehabilitation strategies to improve memory functioning in persons with MS.