Working with clients who have unexplained neurological symptoms can be one of the most challenging parts of clinical practice. These individuals often come to your office after months or years of medical testing, specialist consultations, and growing frustration when doctors find no organic cause for their very real symptoms.

These cases require clinical sensitivity and precise diagnostics. Knowing the proper classification and treatment approaches for these presentations helps in providing effective care and avoiding misdiagnosis or dismissive attitudes toward clients' experiences.

This guide covers Functional Neurological Disorder (FND) and its ICD-10-CM coding, offering practical insights for assessment, documentation, and therapeutic intervention. Whether you're new to these cases or looking to refine your approach, having a clear framework for understanding FND can improve treatment outcomes.

Understanding Functional Neurological Disorder (FND)

Functional Neurological Disorder involves a complex condition where clients experience real neurological symptoms without identifiable organic pathology. These symptoms can include seizures, weakness, tremors, abnormal movements, sensory disturbances, or speech difficulties that don't match traditional neurological diseases.

Recognizing FND as a brain-body disconnect rather than fabrication is key. The symptoms are psychogenic in origin but manifest as real, observable neurological dysfunction that significantly impacts daily life. Brain imaging studies show altered neural connectivity patterns in FND patients, confirming the legitimacy of their experiences.

FND often appears in individuals with histories of trauma, chronic stress, or adverse childhood experiences. The disorder may develop following a triggering event, though not always one that seems obviously traumatic. Clients may present with sudden symptoms or gradual progression over time.

Presentations can vary dramatically. Some clients experience intermittent episodes, while others face constant symptoms. Motor symptoms might include functional weakness, abnormal gait patterns, or non-epileptic seizures. Sensory symptoms can involve numbness, vision problems, or hearing difficulties.

Understanding FND requires moving beyond the outdated "conversion disorder" framework. Modern perspectives recognize FND as a disorder where psychological factors influence neurological pathways, validating clients' experiences and allowing effective psychological intervention. While the ICD-10-CM still uses the category title 'Conversion disorder' (F44.x), modern clinical practice and the DSM-5-TR use the term 'Functional Neurological Symptom Disorder (FND)' to reduce stigma and emphasize the neurological aspect.

ICD-10-CM Coding Basics

Accurate coding for Functional Neurological Disorder requires recognizing that these conditions fall under the psychiatric section of ICD-10-CM, not the neurological codes (G00-G99). This classification reflects the current understanding of FND as a disorder involving psychological factors manifesting as neurological symptoms.

The primary codes for FND include:

• F44.4 - Conversion disorder with motor symptom or deficit (DSM-5-TR: Functional Neurological Symptom Disorder, Motor Symptoms): Used for functional weakness, abnormal movements, gait disturbances, or paralysis
• F44.5 - Conversion disorder with seizures or convulsions (DSM-5-TR: Functional Neurological Symptom Disorder, Seizure/Convulsion Type): Applied to non-epileptic seizures (also called psychogenic non-epileptic seizures or PNES)
• F44.6 - Conversion disorder with sensory symptom or deficit (DSM-5-TR: Functional Neurological Symptom Disorder, Sensory Symptoms): For functional sensory loss, vision problems, or hearing difficulties
• F44.7 - Conversion disorder with mixed symptoms (DSM-5-TR: Functional Neurological Symptom Disorder, Mixed Symptoms): When symptoms from more than one type are present

Documentation requirements for proper coding include:

1. Specific symptom description: Detail the exact neurological symptoms present (tremor type, weakness distribution, seizure characteristics)
2. Functional impairment level: Document how symptoms affect daily activities, work, or social functioning
3. Duration and frequency: Note symptom onset, progression, and episodic patterns
4. Rule-out documentation: Include notes confirming organic causes have been evaluated and excluded

When coding FND, avoid using unspecified codes like F44.9 when more specific options apply. Insurance reviewers look for clear documentation linking symptoms to functional impairment and psychological factors. Including severity specifiers and noting any comorbid conditions helps justify treatment necessity and supports appropriate reimbursement for therapy services.

Assessment and Differential

Accurate assessment of FND requires careful coordination between psychological evaluation and medical workup. Since FND symptoms mimic organic neurological conditions, ruling out structural pathology through comprehensive medical evaluation remains important. This typically involves neurological examination, brain imaging (MRI/CT), and sometimes EEG studies to exclude seizure disorders or other neurological conditions.

Key clinical signs help differentiate FND from organic disorders:

• Hoover's Sign: classic 'rule-in' sign where weakness of voluntary hip extension with normal involuntary hip extension during contralateral hip flexion, its presence supports a positive FND diagnosis based on observation
• Give-way weakness: Initial strong resistance that suddenly collapses
• Distractibility: Symptoms improve when attention is diverted
• Variability: Inconsistent symptom presentation across examinations

Psychological assessment should explore:

• Trauma history: Both recent stressors and childhood adverse experiences
• Dissociative symptoms: Using measures like the Dissociative Experiences Scale
• Current psychosocial stressors: Relationship conflicts, work stress, or life transitions
• Psychiatric comorbidities: Depression, anxiety, PTSD commonly co-occur

Collaboration with neurologists proves invaluable for accurate diagnosis. Many clients benefit from hearing a unified message from both neurological and psychological providers, reducing the stigma of "it's all in your head." Neurologists can provide positive diagnosis based on rule-in signs rather than just exclusion of other conditions.

Documentation should capture both the medical rule-out process and positive FND signs observed. Include specific examples of symptom variability, response to distraction, and any incongruence with known neurological patterns. This comprehensive assessment approach validates the client's experience while establishing the functional nature of symptoms.

Therapeutic Approach

FND treatment starts with thorough psychoeducation that validates the client's experience while explaining the functional mechanisms behind their symptoms. Clients need to know that their symptoms are real neurological events resulting from altered brain-body communication patterns, not imagined or fabricated experiences. Building this understanding helps reduce shame and increases engagement in treatment.

Evidence-based psychological interventions for FND include:

• Cognitive Behavioral Therapy (CBT): Focuses on symptom-specific patterns, helping clients identify triggers and modify responses to physical sensations
• Somatic tracking techniques: Encourages neutral observation of body sensations without judgment or catastrophizing
• Grounding exercises: Develops present-moment awareness to interrupt symptom escalation
• Trauma-focused work: Addresses underlying traumatic experiences when present, using approaches like EMDR or somatic experiencing
• Mindfulness-based interventions: Cultivates non-reactive awareness of symptoms and reduces anticipatory anxiety

Interdisciplinary collaboration greatly improves outcomes. Physical and occupational therapists help retrain normal movement patterns through graded exposure and motor relearning exercises. They work to shift attention away from symptoms while rebuilding confidence in physical abilities. Psychiatrists may address related conditions like depression or anxiety that often accompany FND. Regular communication with the treating neurologist ensures consistent messaging about diagnosis and prognosis.

treatment planning should focus on functional improvement (e.g., ability to walk for 10 minutes, return to part-time work) rather than symptom elimination. Setting realistic goals around daily activities, work participation, and social engagement helps clients measure progress beyond symptom frequency. Sessions often combine psychoeducation, skill-building, and processing of emotional responses to living with FND.

Documentation and Coordination

To effectively document FND, capture both the neurological presentation and psychological factors while ensuring clear communication across the treatment team. Your notes should provide a full picture of the client's functional status and treatment progress.

Key documentation elements include:

• Symptom descriptions: Record specific neurological symptoms observed during sessions, noting variability, triggers, and contextual factors.
• Functional impact assessments: Document how symptoms affect work, relationships, self-care, and daily activities using concrete examples.
• Intervention details: Specify which techniques were used (CBT, somatic tracking, grounding) and the client's response.
• Referral information: Note all interdisciplinary referrals made and the rationale for each.
• Always use Z-codes: Document relevant psychosocial stressors and history of abuse to support the functional origin and medical necessity of the treatment.

Consistent ICD-10-CM coding across providers prevents confusion and ensures continuity. Use the specific F44 codes mentioned earlier rather than general or unspecified codes. Include severity specifiers and document any comorbid conditions like anxiety (F41.1) or PTSD (F43.10) that may influence treatment.

Interdisciplinary communication requires regular updates between team members. Document phone consultations with neurologists, progress reports from physical therapists, and medication changes from psychiatrists. Note when you've shared psychoeducational materials or treatment strategies with other providers.

Progress tracking should highlight functional improvements rather than just symptom frequency. Use standardized measures like the Work and Social Adjustment Scale to quantify changes. Document specific examples of increased activity participation, return to work milestones, or improved social engagement. Track quality of life indicators including sleep patterns, mood stability, and relationship functioning to show comprehensive treatment effectiveness.

Key Takeaways

Working with FND involves acknowledging these symptoms as genuine neurological experiences with functional origins, not fabricated or imagined complaints. Your clients experience real disability that deserves validation and evidence-based treatment, even without identifiable structural pathology.

Accurate ICD-10-CM coding is important for both clinical clarity and reimbursement:

• F44.4: Motor symptoms (weakness, tremor, gait problems)
• F44.5: Non-epileptic seizures
• F44.6: Sensory symptoms (numbness, vision changes)
• F44.7: Mixed presentations

Document specific symptoms, functional impact, and psychological factors to support your chosen code.

Effective treatment combines various therapeutic approaches:

• Validation through psychoeducation: Explain the brain-body disconnect while affirming symptom reality
• Skills training: Teach somatic tracking, grounding techniques, and mindfulness practices
• Body-based awareness: Help clients reconnect with normal movement patterns and sensory experiences
• Trauma-informed care: Address underlying experiences when relevant (but only after significant symptom stabilization and the client has established sufficient somatic and emotional regulation skills)

Collaboration across disciplines is key for optimal outcomes. Regular communication with neurologists ensures consistent messaging about diagnosis. Physical therapists help retrain movement patterns while you address psychological factors. Psychiatrists may manage comorbid conditions affecting recovery.

Success in FND treatment involves shifting focus from symptom elimination to functional improvement. Track progress through increased daily activities, work participation, and quality of life measures rather than just symptom frequency. Remember that recovery often follows a non-linear path, requiring patience and persistence from both therapist and client.

Your role involves managing the complexity of FND while providing structured, evidence-based interventions that respect both the neurological presentation and psychological aspects of this challenging condition.