Proof of concept study on the acute effects on working memory of 10 mg fampridine SR as well as the effects after repeated administration of 10 mg twice daily (3.5 days). The hypothesis ist that fampridine improves working memory performance.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
QUADRUPLE
Enrollment
44
Fampridine SR is an inhibitor of voltage gated potassium channels and is approved in Switzerland for treatment of gait problems in patients with Multiple Sclerosis (MS).
no active component
University of Basel, Transfaculty Research Platform
Basel, Canton of Basel-City, Switzerland
High-load working-memory performance after repeated administrations (3.5 days)
It will be used the letter n-back task (Heck, Fastenrath et al. 2014)) which includes a 3-back task assessing working memory. The 3-back task requires participants to respond to a letter repeat with two intervening letters (for example, S-m-b-s-g…). Performance will be quantified with the d' measure controlling for false positives. It will be used parallel versions (different sequences) for the four test days. Primary outcome will be performance after repeated intake of study medication.
Time frame: test days 2 and 4 (end of treatment periods; 4 hours after last intake of fampridine SR) to assess changes between the Verum and Placebo condition
High-load working-memory performance after acute administration
It will be used the letter n-back task (Heck, Fastenrath et al. 2014)) which includes a 3-back task assessing working memory. The 3-back task requires participants to respond to a letter repeat with two intervening letters (for example, S-m-b-s-g…). Performance will be quantified with the d' measure controlling for false positives. It will be administered parallel versions (different sequences) for the four test days. Primary outcome will be performance after repeated intake of study medication.
Time frame: test days 1 and 3 (beginning of treatment periods; 4 hours after first intake of fampridine SR) to assess differences between the Verum and Placebo condition
Reaction time after acute and repeated intake
Reaction time for correct answers in the 3-back (d') task (see outcomes 1 and 2)
Time frame: test days 1 and 3 (beginning of treatment periods; 4 hours after first intake of fampridine SR) to assess differences between the Verum and Placebo condition
Attention after acute and repeated administration
Performance in a 0-back task (d' measure controlled). It will be used parallel versions (different sequences) for the four test days.
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Time frame: first and last day of treatment periods (each 4 hours after intake in the morning); to assess differences between the Verum and Placebo condition
Symbol Digit Modalities Test (SDMT; Smith 1973) after acute and repeated intake
The test consists of the presentation of a series of 9 symbols, each of them is paired with a single digit, labeled 1-9, in a key at the top of a sheet. The remainder of the page has a pseudo-randomized sequence of the symbols and the participant must respond with the digit associated with each of these as quickly as possible. The score is the number of correct answers in 90 seconds (max. 110). The administration of SDMT will be preceded by a learning sequence at both timepoints. It will be used parallel versions for all test days.
Time frame: first and last day of treatment periods (each 4 hours after intake in the morning); to assess differences between the Verum and Placebo condition
Fluid intelligence (Gf): Bochumer Matrizentest (BOMAT)
Bochumer Matrizentest (BOMAT - advanced -short; Hossiep/Turck/Hasella, 2001, 1st edition), matrix reasoning. It will be administered the BOMAT to measure fluid intelligence (Gf) consisting of 20 items (maximum 20 correct answers possible). Parallel versions will be used for the four test days. It will be used a time-limited version according to Jaeggi (Jaeggi 2010).
Time frame: first and last day of treatment periods (each 4 hours after intake in the morning); to assess differences between the Verum and Placebo condition
Working-memory: Digit Span Task
Working memory will be also assessed with the digit span task, a subtest of the "Wechsler Intelligenztest für Erwachsene" (WIE;(von Aster 2006)). Total scores for digit span forward and backward will be calculated as described in the manual of the WIE. Parallel version will be used for the four test days.
Time frame: first and last day of treatment periods (each 4 hours after intake in the morning); to assess differences between the Verum and Placebo condition
Resting motor threshold (rMT)
The resting motor threshold (rMT) will be measured by transcranial magnetic stimulation (TMS). rMT will be determined by measuring the motor evoked potential (MEP) in the abductor digiti minimi according to Rossini (2001). rMT will be defined as the lowest stimulation intensity by stimulating the primary motor cortex of the left or right hemisphere required to induce an MEP in the abductor digiti minimi of the dominant hand in at least 5 out of 10 trials.
Time frame: test days 2 and 4 (last day of treatment periods; approx. 5 hours after last intake of fampridine SR) to assess differences between the Verum and Placebo condition