Functional Neurological Disorder (FND) is one of the most clinically complex and most frequently misunderstood conditions in the neurology and disability sectors. It is a common condition — FND accounts for 10 to 20 per cent of presentations to neurology clinics — yet it is also one of the most underserved. In Australia, a 2026 study from a tertiary FND clinic found that 42.9 per cent of participants were unable to work because of FND, 67.6 per cent had presented to an emergency department at least once and the average time from diagnosis to clinic assessment was 356 days. As of March 2025, the Australian Institute of Health and Welfare (AIHW) reported 530 registered NDIS plans where FND was listed as the primary or secondary condition — a small number relative to the prevalence of the condition, reflecting the significant barriers to NDIS access that people with FND face.

What is Functional Neurological Disorder?

Functional Neurological Disorder is a condition in which the nervous system produces neurological symptoms without structural damage or neurological disease. The brain and body are sending and receiving signals incorrectly, disrupting normal neurological functioning and producing real, involuntary symptoms that can include weakness, paralysis, tremor, gait disturbance, seizure-like episodes and sensory changes. In DSM-5, FND is classified as Functional Neurological Symptom Disorder under the Somatic Symptom and Related Disorders chapter. In ICD-11 it is classified as Dissociative Neurological Symptom Disorder (F44).

The most important clinical fact about FND is that it is a positive diagnosis. It is made on the basis of specific clinical signs that indicate the nervous system is functioning abnormally, not on the absence of findings on neurological investigation. FND is not a diagnosis of exclusion. It is not a euphemism for a psychological problem or for unexplained symptoms. The symptoms are neurological, real and involuntary. The person with FND is not feigning, exaggerating or imagining their symptoms.

The historical name for the condition was conversion disorder, reflecting an outdated theoretical framework that has been superseded. The contemporary neurological model understands FND as arising from a disorder of brain network function — specifically in the networks involved in the integration of voluntary movement, attention and predictive processing — producing symptoms that are genuine consequences of abnormal brain functioning rather than structural damage.

FND: key clinical points for NDIS documentation

FND symptoms are real and involuntary. They are not feigned, exaggerated or psychosomatic in the sense of being imaginary.

FND is a positive neurological diagnosis made on specific clinical signs, not a diagnosis made by excluding other conditions.

The absence of structural abnormality on MRI or other neurological investigation does not mean the person is not disabled. FND produces genuine, measurable functional impairment.

The attention-sensitive nature of some FND symptoms — where symptoms may temporarily improve with distraction or worsen when attention is directed to the affected body part — is a clinical feature of the condition, not evidence of feigning.

Psychological and emotional factors are commonly associated with FND but are not present in all cases and are not required for the diagnosis.

FND commonly co-occurs with other conditions including fibromyalgia, chronic fatigue syndrome and anxiety disorders, which can compound the functional impairment.

Types of FND symptoms

FND presents with a range of neurological symptom types that can occur individually or in combination. Most people with FND experience more than one symptom type simultaneously. The specific symptoms present have direct implications for the nature of the functional impairment and what the Functional Capacity Assessment must document.

FND and fibromyalgia: understanding the overlap and the differences

Fibromyalgia is one of the most common co-occurring conditions in FND. Both conditions are frequently encountered together and are frequently confused with each other by people who have the diagnoses, by their families and sometimes by non-specialist clinicians. Understanding the distinction between them is clinically important for the Functional Capacity Assessment.

How FND affects daily functioning

Mobility and community access

Functional weakness of the lower limbs, functional gait disorder and functional seizures all directly affect the ability to walk safely and reliably in the home and community. The unpredictable nature of many FND symptoms means the person may be mobile on some days and unable to walk at all on others. Functional seizures in particular restrict independent community access because of the unpredictable loss of consciousness or control they produce. The person may be unable to drive, use public transport independently, swim or participate in any activity where a sudden loss of motor control or consciousness would create a serious safety risk.

Self-care and personal activities of daily living

Functional weakness and tremor affecting the upper limbs, fatigue and pain all affect the capacity for self-care including showering, dressing and meal preparation. The fluctuating nature of FND symptoms means the person may complete self-care independently on a good day and require full or partial assistance on a bad day. The Functional Capacity Assessment must document the full range of self-care capacity and the level of support required on poor-symptom days, not only on good-symptom days.

Employment and social participation

The Australian tertiary clinic data published in 2026 found that 42.9 per cent of people with FND were unable to work. Functional seizures, unpredictable motor symptoms, fatigue and cognitive symptoms collectively and individually create significant barriers to maintaining employment. Social participation is affected by the unpredictability of symptoms, the fatigue associated with social effort and the stigma and misunderstanding that people with FND frequently encounter.

Fatigue

Fatigue in FND is profound and has both a neurological and a cognitive component. The effort required to manage voluntary movement in a nervous system where normal motor control is disrupted is neurologically costly. Cognitive effort — concentration, decision-making, navigating complex environments — is similarly draining. The post-exertional pattern of fatigue in FND bears similarities to the fatigue pattern in ME/CFS and must be documented with the same specificity: what triggers it, when it occurs in the daily cycle, what its functional consequences are and how it affects the sustainability of daily activities across a full week.

The diagnostic and assessment challenges specific to FND

Functional Capacity Assessment for FND presents specific challenges that are not present in assessments for structurally-caused neurological conditions. The assessor must understand these challenges to conduct an assessment that accurately captures the person’s functional situation.

Symptom variability and attention sensitivity

Many FND symptoms fluctuate significantly in severity and can temporarily improve when the person is distracted from the affected body part or worsen when attention is directed to it. This is a well-described clinical feature of FND and is one of the positive signs used to make the diagnosis. It does not indicate feigning. However, it creates a specific challenge for the Functional Capacity Assessment: observing a person completing a task during a single session may capture a moment of relative ability that is not representative of typical daily functioning.

The Functional Capacity Assessment must gather detailed collateral history about typical daily functioning from the person and their family or carers across different times of day and different symptom states. Assessment during a single clinical session must be interpreted in the context of this wider picture. The assessment should document clearly what the person’s functioning looks like on good days and on poor days and what proportion of time is typically spent in each state.

Establishing permanence for NDIS access

Establishing permanence is one of the primary challenges for NDIS access with FND. Some people with FND recover fully or substantially with appropriate treatment. Others have chronic, refractory FND that persists despite appropriate intervention. The NDIS requires that the impairment is permanent or likely to be permanent.

For a person with chronic FND where symptoms have been present for more than six months, have not substantially responded to appropriate treatment and show no current clinical trajectory toward resolution, the case for permanence can be made. The Functional Capacity Assessment must document the treatment history in detail: what treatments have been tried, for how long, what outcome was achieved and why the current clinical picture supports the conclusion that the impairment is likely to be permanent rather than temporary. Where the treating neurologist has provided an opinion on prognosis, this should be included.

FND and NDIS access

FND is not included in NDIS Condition List A or List B by name. NDIS access requires functional evidence demonstrating substantially reduced functional capacity. As of March 2025, the AIHW reported only 530 registered NDIS plans where FND was listed as the primary or secondary condition, a number that substantially underrepresents the population with FND who would benefit from NDIS support. The primary barriers to NDIS access for people with FND are the challenges of establishing permanence, the lack of familiarity with FND among some NDIS planners and the fluctuating and sometimes invisible nature of the functional impairment.

A Functional Capacity Assessment that specifically documents the neurological basis of the functional impairment, the positive clinical features that establish the FND diagnosis, the functional consequences across good and poor symptom days and the treatment history and permanence evidence provides the strongest available clinical foundation for NDIS access.

What a Functional Capacity Assessment covers for FND

• Documentation of the specific FND symptom types present, their frequency, duration, severity and the pattern of fluctuation across days and weeks
• Assessment of mobility and community access and how functional seizures, functional weakness or functional gait disorder affect the safety and reliability of movement
• Assessment of upper limb function and fine motor capacity and how functional tremor, weakness or sensory symptoms affect daily task performance
• Assessment of self-care capacity across the full range of symptom states, documenting the level of support required on poor-symptom days
• Assessment of cognitive symptoms and their impact on daily task management, service engagement and employment capacity
• Assessment of fatigue and its pattern across the day and week, including post-exertional fatigue following activity
• Assessment of pain and sleep disturbance and their contribution to overall functional impairment
• Assessment of the functional impact of co-occurring conditions including fibromyalgia, ME/CFS and anxiety disorders
• Assessment of safety risks arising from functional seizures or sudden loss of motor control
• Documentation of the treatment history including the treatments tried, the duration of treatment and the outcomes achieved, as evidence relevant to the permanence determination
• Specific recommendations across each NDIS functional domain grounded in direct observation across the best and worst functional states available during the assessment period

The 2026 NDIS context

The Securing the NDIS for Future Generations Bill 2026, introduced to Parliament on 14 May 2026, strengthens the requirement that NDIS supports must have a direct causal connection to the eligible impairment. For people with FND, this means the Functional Capacity Assessment must explicitly document the neurological basis of the functional impairment and the direct causal link between the FND presentation and each area of functional limitation. The clinical complexity of FND — the fluctuating symptoms, the attention sensitivity and the challenges of establishing permanence — make a comprehensive, specifically adapted Functional Capacity Assessment particularly important.

Who can refer?

Referrals are accepted from participants and families, support coordinators, neurologists, GPs and allied health professionals. Sina OT has completed Functional Capacity Assessments for individuals with functional neurological disorder and related presentations across Adelaide, Melbourne and Sydney. All assessments are completed in person in the participant’s home and community environment.

Refer to Sina OT

Sina OT is an independent Occupational Therapy practice providing Functional Capacity Assessments across Adelaide, Melbourne and Sydney.

Sina OT has completed Functional Capacity Assessments for individuals with functional neurological disorder and related presentations. All assessments are completed in person in the participant’s home and community environment by a registered Occupational Therapist.

Services are available in English and Farsi (Persian).