Please assess the completion status of the following clinical trial:

Trial Title: Influence of Fampridine on Working Memory in Individuals With Post COVID-19 Condition With Subjective Cognitive Impairment

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: CROSSOVER
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: QUADRUPLE
- Phase: None
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* male or female;~* a valid positive PCR test or a documented certified rapid antigen test or a virus-specific antibody (nucleocapsid) test for COVID-19 issued at least 3 months prior to study;~* Above medium subjective working memory impairment (at least much worse in item 1a part 2 (cognitive abilities) of the Covid-Q screening questionnaire;~* present at least 3 months after COVID-19 infection and lasting for at least 2 months. (The impairment must have emerged after COVID-19 infection and cannot be explained by an alternative diagnosis);~* normotensive (BP: 90/60mmHg - 140/90mmHg);~* BMI: 19.0 - 40.0 kg/m2;~* Age: 18 - 69 years;~* fluent German-speaking;~* IC as documented by signature.~Exclusion Criteria:~* initiation of pharmacological treatment or change of dose within the 30 days preceding the present study~* contraindications to the class of drugs under study, e.g. known hypersensitivity or allergy to 4-aminopyridine~* use of potassium channel blockers within the last 3 months~* concomitant treatment with OCT 2 inhibitors and -substrates (e.g. cimetidine, propranolol)~* acute or chronic psychiatric disorder (e.g. major depression, psychosis, somatoform disorder, suicidal tendency)~* acute cerebrovascular condition~* history of seizures~* risk of lowered seizure threshold (due to e.g. sleep deprivation, withdrawal of alcohol after alcohol abuse)~* renal impairment~* history of malignant cancers~* walking problems (e.g. due to dizziness)~* other clinically significant concomitant disease states that could pose a safety risk (e.g. hepatic dysfunction, cardiovascular disease, urinary tract infection)~* bradycardia \< 50/min during clinical examination~* clinically significant laboratory or ECG abnormality that could be a safety issue in the study~* known or suspected non-compliance (e.g. missing more than one dose of study medication per intervention phase)~* drug or alcohol abuse~* inability to follow the procedures of the study, e.g. due to language or psychological problems of the participant~* participation in another study with an investigational drug within the 30 days preceding and during the present study~* enrolment of the investigator, his/her family members, employees and other dependent persons~* pregnancy or breast feeding~* Intensive care treatment due to COVID-19 infection.~Exclusion Criteria concerning TMS measurement~* metal in the brain, skull or elsewhere in the body (e.g., splinters, fragments, clips, etc.)~* implanted neurostimulator (e.g., DBS, epidural/subdural, VNS)~* cardiac pacemaker or intracardiac lines~* medication infusion device~* piercings in the head area, pivot teeth (retainers are no exclusion criterion)~* tattoos (in the head area) with metallic inks or newly stung tattoos (\< 3 months), as newly stung tattoos can be damaged by a magnetic field;~* condition after neurosurgery~* hearing problems or tinnitus~* not able to sit still due to tremor, tics, itching~* History of repeated syncope~* head trauma diagnosed as concussion or associated with loss of consciousness~* diagnosis of epilepsy, or a convulsion or a seizure in the past of the participant or his family~* TMS in the past showing problems~* MRI in the past showing problems~* surgical procedures to spinal cord~* spinal or ventricular derivations TMS measurement is optional. If a participant is eligible for the study, but prefers not to undergo TMS measurement or meets one or more exclusion criteria for TMS measurement, the participant can nevertheless be included in the study without rMT measurement using TMS.

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: 69 Years
- Healthy Volunteers: f

Study Arms:
- Fampridin SR (Type: EXPERIMENTAL): Active study medication consists of 7 tablets of fampridine SR 10 mg formulated for oral administration taken in the morning and evening 12 h apart without food. Tablets must be administered whole.~There will be a washout period of at least 8 days equaling over 30 half-lives of the active substance fampridine (t½ = 6 h) between experimental and control intervention and up to 26 days depending on the individual scheduling of each subject.
- Placebo (Type: PLACEBO_COMPARATOR): Identically looking placebo tablets consisting of widely identical additives formulated for oral administration.

Based on this trial design, predict the completion outcome and termination type (if applicable).