Cognitive Deficits In Multiple Sclerosis

The aim of the present study was to determine whether a Cognitive decline, related to Multiple Sclerosis (MS), also involves deficits in Semantic Memory.

Semantic Memory function was evaluated by studying the conscious understanding of conceptual meanings.

A group of MS patients with Cognitive decline was presented with four tasks concerning concepts, their attributes and relationships to other concepts.

The tasks were designed to measure Spontaneous, Cued and ReCognition performance separately. The patients had difficulties in understanding conceptual meanings.

Easing the retrieval demands of the tasks did not help them to improve their performance which was poorer than the control group's on every task used.

The results indicate a Retrieval Deficit combined with an underlying Storage Deficit in the Semantic Memory of MS patients with Cognitive decline.

Introduction
In the present study, the pattern of memory and learning deficits in two Cognitively different, but clinically and demographically similar, Multiple Sclerosis (MS) groups was compared.

Material & Methods
23 patients represented the Cognitively preserved MS group and 22 patients the MS group with early Cognitive decline. A control group of 35 healthy controls was also included.

The Cognitive status of the subjects was defined using the Mild Deterioration Battery (MDB).

Furthermore, all subjects were given a set of memory and learning tests and were instructed to evaluate the frequency of their memory and learning difficulties.

The Mini-Mental State Examination (MMSE) was also administered to all subjects.

Results
The Cognitively deteriorated patients, even those with normal MMSE performance, showed widespread memory and learning deficits, but adequate self-evaluation of their everyday memory and learning difficulties.

The preserved group, in turn, performed similarly to the controls.

Conclusion
Widespread memory and learning deficits are associated with relatively mild Cognitive decline in MS.

These deficits were observable in the intermediate-length screening battery, the MDB, but not in the MMSE.

The present study suggests that the accuracy of patients' own evaluations of their memory and other Cognitive problems is superior to the results of very brief screening batteries, like the MMSE.

Therefore, brief screening in NeuroPsychological assessment of MS patients is not recommendable.

Patients frequently complain of distractibility and difficulty attending to more than one thing at a time.

And several NeuroPsychological studies have found evidence for a specific Attention Deficit without general NeuroPsychological Impairment.

The present study examined the nature of Attentional Disturbance after MTBI using an extended version of the 2 and 7 Test.

Which introduced two conditions reflecting patients' subjective complaints: the ability to perform with background 'noise', and while simultaneously attending to a secondary task.

The Dual Task Demands produced a significant Slowing In Processing Speed for both the MTBI patients and control subjects.

However, the relative Decline In Processing Speed appeared much greater for the patients with MTBI, and they differed from control subjects only in this condition.

The results are consistent with findings that patients with MTBI exhibit relatively subtle Cognitive deficits.

Which are apparent primarily under conditions that require effortful or controlled Cognitive processing and exceed their available Cognitive resources.

Thus, the Attentional Deficits apparent during Dual Task Demands may represent decreased Cognitive, and perhaps Neural efficiency, which reflects MTBI patients' subjective complaints and functional impairments.

Although the mechanisms of Cognitive Impairment in Multiple Sclerosis (MS) have been extensively studied, evaluation of Language Functions has been given little attention.

In the present study, we evaluated whether impairment of Language Functions is associated with Cognitive decline in MS.

We studied naming, reading, and writing performance of two carefully matched patient groups differing only with respect to Cognitive status.

In Language Tasks, the patients with incipient Cognitive decline not only demonstrated performance slowness, but also made more errors than the patients with preserved Cognitive capacity and the healthy controls.

The comprehensive Naming Error analysis revealed that the Cognitively deteriorated patients produced error types not present in the other two study groups.

Contrary to previous suggestions, the present study indicates that Impaired Language performances in MS are attributable to mild Cognitive deterioration rather than to Sensory or Motor factors.

Thus, assessment of Language Functions should be included in NeuroPsychological evaluations of MS patients.

We studied the relationships between Magnetic Resonance Imaging (MRI) and the Luria-Nebraska NeuroPsychological Battery (LNNB) in 64 patients with Relapsing/Remitting Multiple Sclerosis (MS).

MRI films were scored according to arbitrary descriptive criteria designed to emphasize patterns of alterations. Five groups were created:

1. Group 1 and 2 had typical discrete White Matter Lesions
2. Group 3 had confluent lesions
3. Group 4 had large discrete lesions
4. Group 5 had only few small lesions
5. Groups 2 and 3 had evidence of Parenchymal Atrophy

Groups 2 and 3 were the most impaired on the LNNB, but none of these patients was actually Demented. Groups 1 and 5 were globally intact in spite of very different mean age and MRI pattern.

Group 4 was composed of younger subjects with a shorter disease duration; they showed mild loss of Attentive and Abstracting Abilities.

We suggest that since their MRI was showing greater signs of local biological activity their mental deficits may be a transitory condition capable of two distinct outcomes:

1. A favorable one as in groups 1 and 5
2. A slowly progressive one associated with loss of Brain tissue as in groups 2 and 3

This brief article reviews the present state of knowledge concerning the relationship between structural and functional Cerebral abnormalities and the Cognitive deficits associated with Multiple Sclerosis.

Currently available NeuroImaging techniques have substantially contributed to a better understanding of the latter, suggesting that Cortical-SubCortical disconnection is the most likely cause of the Cognitive disturbance.

Longitudinal studies are needed to determine the natural history of the Cognitive deficit and its relationship to the Cerebral changes detected by NeuroImaging techniques.

Although changes in Cognitive function in patients with Multiple Sclerosis (MS) have been reported, these changes have been traditionally associated with the later stages of the disease.

In the current study, a comprehensive NeuroPsychological battery was administered to MS patients (N = 86) in whom the disease progression was relatively mild and in remission and a demographically well-matched control group (N = 46).

Besides the expected differences in tests of Motor Function, the two groups also differed on a number of Cognitive tests with no motor demands.

The two Cognitive functions that appear impaired were Learning and Memory.

Given that similar deficits have been found in MS patients with more severe symptoms, it is argued that changes in Cognitive function can occur in the mild stages of the disease.

To determine whether different portions of the Corpus Callosum (CC) are responsible for transferring the information of specific Cognitive modalities, eighteen females with Relapsing/Remitting Multiple Sclerosis (MS) were studied using NeuroPsychological procedures and Magnetic Resonance Imaging (MRI).

Measures of both Anterior and Posterior CC areas were obtained in patients with MS as well as in eighteen age and sex matched healthy controls.

MRI scans were additionally analyzed for each patient in order to evaluate the extent of DeMyelinating lesions in both PeriVentricular and SubCortical areas.

Patients with MS exhibited a significant decrease in both the Anterior and Posterior CC areas compared with normal subjects.

The results of statistical analysis showed that, even when the effect of DeMyelinating lesions was taken into account within a regression equation, the Atrophy of Anterior CC area strongly affected the performance on Verbal Fluency Task.

These data emphasize the importance of the Anterior CC area for the InterHemispheric transfer of Cognitive information associated with Verbal Fluency.

Background
Whole-Brain N-Acetyl Aspartate (NAA), a measure of Neuronal function, can be assessed by multislice Echo-Planar Spectroscopic Imaging.

Objective
To test the hypothesis that the global Brain NAA/creatine (Cr) ratio is a better predictor of Cognitive Dysfunction in Multiple Sclerosis than conventional Magnetic Resonance Imaging measures.

Design & Setting
Survey research-oriented hospitals.

Patients
Twenty patients, 16 women and 4 men (mean age, 36 years), with early Relapsing/Remitting Multiple Sclerosis (mean Expanded Disability Status Scale score, 2.5).

Main Outcome Measures
Correlation between the global NAA/Cr ratio and a Cognitive Dysfunction factor comprising 16 measures from an extensive NeuroPsychological test battery that best distinguished patients with Multiple Sclerosis from healthy control subjects.

Results
A significant partial correlation between the global NAA/Cr ratio and the Cognitive Dysfunction factor was found (partial r = 0.62, P = .01).

And 9 Cognitively impaired patients had significantly lower global NAA/Cr ratios than 11 unimpaired patients (P = .04).

No significant correlations were found between the Cognitive Dysfunction factor and conventional Magnetic Resonance Imaging measures (ie, Brain Parenchymal Fraction and Lesion Volume).

Conclusions
Multislice Echo-Planar Spectroscopic Imaging provides global metabolic measures that distinguish between Cognitively Impaired and unimpaired patients with Multiple Sclerosis and correlate with a global Cognitive measure.

Standardization of the technique is needed, and larger-scale studies that include healthy controls are suggested.