Definition: chronic, inflammatory and autoimmune disease that affects the central nervous system (CNS), especially the brain and spinal cord.

• Characterized by demyelination (damage to the protective myelin sheath around nerves), axonal damage and neurodegeneration.

• Affects more than 2 million people worldwide and occurs 2 to 3 times more women than men.

• Typically occurs between ages 20 and 40.

• It's the leading non-traumatic cause of neurological disability in young adults.

Main Clinical Types:

• RRMS (Relapsing-Remitting MS): 

  • Represents 70% to 80% of cases

  • Characterized by episodes of acute neurological deterioration (relapses), followed by partial or complete recovery (remission);

  • No progression of disability occurs between relapses during the early stages;

  • Appearance of new or recurrent symptoms that last for at least 24 to 48 hours, develop over days to weeks.

• SPMS (Secondary Progressive MS):

  • 50% to 70% of RRMS patients transition to SPMS within 10–20 years after disease onset.

  • Characterized by a continuous progression of disability over time, with or without additional relapses.

  • Symptoms gradually worsen without full recovery after relapses.

• PPMS (Primary Progressive MS):

  • Represents 10% to 15% of the cases

  • Characterized by a rapid progressive deterioration from the onset of the disease without clear relapses and remissions.

  • Symptoms may progress at varying rates but do not improve significantly.

Causes and Risk Factors:

• Influenced by a combination of both genetic and environmental factors.

• Low vitamin D levels, a history of Epstein-Barr virus (EBV) infection, and smoking have all been associated with a higher risk of developing the disease

• Although MS is not directly inherited, having a family history does raise the likelihood of diagnosis.

Symptoms:

• A broad range of symptoms associated with MS and they manifest differently between patients.

• Common symptoms impacting the social and physical functioning of people include:

  • Fatigue, cognitive impairment, coordination and balance problems, weakness, pain and depression

Diagnosis:

• Established by considering patient's history and physical examination, along with magnetic resonance imaging (MRI) findings, cerebrospinal fluid analysis and evoked potentials tests.

• Clinically, a diagnosis of multiple sclerosis is supported by evidence of one or more relapses, which can be confirmed through objective clinical evidence of one or more lesions or objective clinical evidence of one lesion with reliable historical evidence of a prior relapse.

• Differential diagnosis:

  • Other demyelinating or inflammatory CNS syndromes;

  • General inflammatory and autoimmune syndromes;

  • Infectious etiologies;

  • Vascular etiologies;

  • Metabolic causes;

  • Uncommon genetic etiologies;

  • Neoplastic causes include primary CNS malignancies, such as gliomas and meningiomas, or metastasis

Treatment:

• There is no cure for the disease, however, disease-modifying therapies (DMTs) can reduce relapses and delay progression of the MS.

• Immediate treatment initiation upon diagnosis is crucial for multiple sclerosis.

• Short-term goals focus on decreasing MRI lesion activity, while long-term goals aim to prevent secondary progressive multiple sclerosis.

• Post-treatment challenges include ensuring patient compliance and monitoring for drug toxicity.

• Prevalence: 40–70% of patients, even in early stages.

• Information Processing Speed: Slowed mental speed.

• Attention: Difficulties sustaining and dividing attention.

• Working and Episodic Memory: Challenges with recall, manipulation of info.

• Executive Functions: Poor planning, flexibility, problem-solving.

• Verbal Fluency: Slowed verbal expression.

  
  

Perceptual Deficits:

• Visual Problems (e.g., optic neuritis).

• Visuospatial Issues: Difficulty reading maps, parking, orienting.

• Sensory Integration Problems: Trouble processing tactile, visual, and proprioceptive input.

Goal: To improve work ability, social relationships and overall quality of life.

Traditional Cognitive Intervention:

1. Cognitive Training:

   • Exercises to improve attention, working memory, processing speed.

   • Delivered via paper-pencil tasks or digital platforms like RehaCom and Cognitive Rehabilitation for Attention and Memory (CRAM).

2. Compensatory Strategies:

   • Use of external aids (e.g., agendas, reminders).

   • Task simplification (chunking).

   • Energy conservation strategies.

3. Metacognitive Training:

   • Awareness of deficits and self-monitoring.

   • Adapting strategies to enhance autonomy.

Critical Factor for Success: Individualizing the rehabilitation plan is essential for successful intervention.

Key Considerations:

• The type and degree of cognitive deficits the patient experiences.

• The stage of the disease (early or advanced stages).

• The patient’s preferences and motivation to engage with tasks and training.

Personalization ensures the intervention has a positive impact and motivates the patient to continue with the training, with continuous positive feedback.

Mechanism: It adjusts the electrical activity in specific brain regions by altering the polarity of nerve cells:

• Anodal stimulation increases neuronal activity.

• Cathodal stimulation inhibits neuronal activity.

Goal: To influence cognitive and neuropsychological functions, improving cognitive performance and recovery of impaired functions like memory, attention, and information processing.

Attention, Fatigue and Working Memory: 

• Repeated anodal tDCS on the left dorsolateral prefrontal cortex

  
  

Synergistic Effects with Cognitive Training: When combined with cognitive training programs, tDCS may have a synergistic effect, enhancing cognitive performance in memory and attention tasks.

• No consensus on ideal parameters - current intensity, duration, number of sessions.

• Wide variability in study - difficult to compare results and establish effective protocols.

Variability in Results

• Individual responses differ significantly.

• Factors influencing variability may include:

  • Location of brain lesions

  • Stage of MS

Long-Term Effects

• Positive effects are often observed short-term.

• There is insufficient evidence regarding the sustainability of these effects over the long term.

Mechanism and Goals

• Modulates cortical excitability, promoting neuroplasticity.

• Cognitive training targets specific domains like attention, memory, and executive functions.

• The combination boosts the effectiveness of both methods.

Compensatory Brain Plasticity

• This multimodal strategy supports compensatory brain plasticity, vital in progressive and inflammatory conditions such as MS.

• Neuroplasticity is the brain's ability to reorganize and adapt after injury or degeneration.

Combined Neuromodulation and cognitive training, offers an effective pathway for cognitive rehabilitation in MS, enhancing both stimulation effects and plasticity.

Diagnosis: Relapsing-Remitting Multiple Sclerosis (RRMS)

Cognitive Deficits: Attention, processing speed, working memory, executive functioning

Other Symptoms: Cognitive fatigue, mild depression, reduced participation in daily activities

Main Goal: To improve cognitive functioning and reduce cognitive fatigue and mild depression through a multimodal intervention.

Specific Objectives:

Objective 1: Improve Sustained and Divided Attention:

• Attention deficits are common in MS, especially sustained and divided attention, due to white matter lesions in frontoparietal networks.

Objective 2: Improve Working Memory and Processing Speed:

• Working memory and processing speed are commonly impaired due to demyelination and slowed neural conduction.

  
  

Objective 3: Strengthen Executive Function (Planning, Problem Solving, Flexibility):

• Executive dysfunction results from frontal lobe disconnection and reduced prefrontal efficiency in MS.

  
  

Objective 4: Reduce Cognitive Fatigue:

• Cognitive fatigue is a hallmark of MS, often independent of depression, and associated with reduced cortical excitability.

  
  

Objective 5: Generalize Cognitive Gains to Daily Life:

• Cognitive improvements must be integrated into functional everyday activities to be meaningful.

Monitoring: Weekly therapist check-ins for adaptation and engagement.

Justification: Proven efficacy in MS for improving verbal performance, mental processing and functional independence.

Protocol:

• Intensity: 2 mA

• Duration: 20 minutes

• Frequency: 2x/week (before cognitive training)

• Placement: Anode-over F3 (left DLPFC); Cathode-over Fp2 (right supraorbital area) or right shoulder (to avoid interfering with cortical areas)

Justification: Enhances effects of cognitive training and reduces fatigue.

• Use of digital calendars/reminders

• Energy management: planned breaks, task prioritization

• Cognitive rest: structured downtime to avoid overload

Justification: Improve self-regulation and foster independence.

Mechanisms:

• Promotes remyelination and synaptic plasticity.

• Reduces neuroinflammation by modulating immune responses.

• Enhances brain connectivity and compensates for demyelination-related functional loss.

Cognitive Impairment: attention and working memory.

• Stimulates dorsolateral prefrontal cortex (DLPFC) to enhance cognitive networks.

Motor Symptoms: spasticity, gait, and motor coordination.

• Primary motor cortex (M1).

Fatigue:

• Modulating thalamocortical circuits.

Pain and Mood Disorders:

• stimulation of the dorsolateral prefrontal cortex helps alleviate depressive symptoms.

Protocols & Parameters:

• Repetitive TMS (rTMS) is commonly used (low or high frequency).

• Protocols vary depending on symptom and patient profile.

• Effects are dose-dependent and may require repeated sessions.

• Digital Cognitive Training (e.g., RehaCom, BrainHQ, CogniFit): Improves attentional control and speed.

• Dual-Task Training: Enhances divided attention and cognitive flexibility in functional contexts.

• Neuromodulation – tDCS over Right Dorsolateral Prefrontal Cortex (DLPFC) (F4):

  • Enhances sustained attention and vigilance.

• n-back Training: Enhances adaptive memory updating.

• Chunking and Mnemonics: Boosts memory encoding and retrieval.

• Neuromodulation – tDCS over Left DLPFC (F3):

  • Anodal tDCS shown to improve working memory performance in MS.

• Goal Management Training: Shown to improve executive control .

• Problem-Solving Therapy: Enhances structured decision-making.

• tDCS – Bilateral Prefrontal Stimulation (F3/F4):

  • Promotes broader executive function activation.

• Energy Conservation Techniques: Activity scheduling and rest management.

• Cognitive Behavioral Therapy and Mindfulness: Targets fatigue and emotional dysregulation.

• Neuromodulation – tDCS over M1 or ACC:

  • M1 stimulation shown to alleviate fatigue perception.

• Real-Life Task Simulation: Role-playing and ADL simulations (e.g., cooking, managing schedules).

• Metacognitive Strategy Training: Improves self-awareness and task monitoring.

• Caregiver/Home Involvement: Improves generalization and adherence.

• Intensity: 1,5-2 mA

• Duration: 20 minutes

• Frequency: 3–5 sessions per week for 2–4 weeks

• Placement: Anode-F3 (Left DLPFC); Cathode-F4 (Right DLPFC)

Justification: Dual-site stimulation enhances inter-hemispheric balance, particularly in conditions with cognitive fatigue, depression, or attention deficits

Protocol:

• Intensity: 1,5-2 mA

• Duration: 20 minutes

• Frequency: 3–5 sessions per week for 2–4 weeks

• Placement: Anode-over C3 or C4 (depending on target side); Cathode - over contralateral supraorbital area or shoulder

Justification: M1 - Motor enhancement, fatigue, pain; ACC

Fatigue, pain, emotion, cognitive control

• SDMT – Processing speed

• PASAT – Working memory & divided attention

• MFIS – Cognitive fatigue

Qualitative Feedback: Patient-reported improvements in organization, reading, and focus.

Goal: gain in cognitive scores and reduction in fatigue.