Introduction: cognitive dysfunction in multiple sclerosis

Trail Making Test Could Predict Impairment in Cognitive Domains in Patients with Multiple Sclerosis: A Study of Diagnostic Accuracy

OBJECTIVE

Cognitive impairment (CI) and executive dysfunction (ED) are prevalent in patients with multiple sclerosis (PwMS). The Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) is the gold standard neuropsychological battery (NPB) for detecting CI. Delis-Kaplan Executive Function System (DKEFS) NPB evaluates ED. We aimed to find practical test(s) from DKEFS with acceptable diagnostic utility for early detection of impairment in cognitive and executive domains.

METHODS

Cognitive and executive tasks, physical disability, and depression scores of 30 PwMS were assessed (17 women, age: 38.1). Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test (PASAT), and Controlled Oral Word Association Test (COWAT) from MACFIMS and Trail Making Test (TMT), Design Fluency Test (DFT), and Verbal Fluency Test (VFT) from DKEFS were selected. The association between patients' characteristics and performance in tests, and diagnostic accuracy of DKEFS tests in detecting impairment in cognitive tasks were evaluated, using Pearson correlation and receiver operator characteristic curve analyses, respectively.

RESULTS

A significant correlation was found between disease duration and SDMT and TMT subtests. Expanded Disability Status Scale was significantly related to SDMT, VFT-switching, and TMT subtests. Beck Depression Inventory was significantly related to DFT. TMT-switching detected abnormalities in SDMT and PASAT with 100% sensitivity, 93.3% (for SDMT), and 85.7% specificity (for PASAT). TMT-letter showed 100% sensitivity and 90% specificity in identifying abnormalities in COWAT.

CONCLUSIONS

TMT, particularly the switching condition, is a practical paper-based test that could predict impairment in cognitive tasks. Clinicians may use TMT as a screening tool among PwMS.

Effects of 4-aminopyridine on attention and executive functions of patients with multiple sclerosis: Randomized, double-blind, placebo-controlled clinical trial. Preliminary report

BACKGROUND

A high percentage of patients with multiple sclerosis present cognitive alterations. Because 4-aminopyridine improves nerve conduction and efficient synaptic connection could improve cognitive dysfunction.

OBJECTIVE

To evaluate the efficacy on cognitive performance and safety of 4-aminopyridine administered to patients with relapsing-remitting multiple sclerosis.

METHODS

A randomized, double-blind, placebo controlled clinical trial was conducted in patients with relapsing-remitting multiple sclerosis diagnosis according to the McDonald criteria. At the beginning and at the end of the treatment different tests were used to assess cognitive performance. Subsequently, patients were randomized 1:1 to receive treatment or placebo. A bootstrap-t test was proposed to test the effectiveness of cognitive performance, considering a p-value < 0.05 as statistically significant.

RESULTS

Twenty-four patients were recruited of which 21 completed the trial, 11 with 4-aminopyridine and 10 with placebo treatment. No significant differences between groups in the initial assessments were observed. In terms of efficacy, the experimental group achieved significantly higher scores in attention span, verbal fluency, planning and graphics and constructive motion.

CONCLUSIONS

4-aminopyridine proved to be an effective treatment on cognitive aspects in patients with relapsing-remitting multiple sclerosis. Drug doses were shown to be safe with mild to moderate adverse events (ClinicalTrials.gov number, NCT02280096).