Functional Gait Disorders: Clinical presentations, Phenotypes and Implications for treatment

Figures & data

Figure 1. Reported functional motor symptoms (blue) and non-motor symptoms (green) that occur in motor-FND that may contribute to presentations of FGD.

Table 1. A summary of the reported phenotypes of functional gait disorders.

Phenotypes	Description
Psychogenic Rhomberg	Patients may fall toward or away from the tester Large amplitude body sway, building up after a silent latency of a few seconds Improvement of postural balance when the patients are distracted (39)
Uneconomic postures	High muscle energy demands in order to maintain difficult postures with an eccentric displacement of the center of gravity or flexed knees and hips (39)
Walking on ice	Cautious, wide-based steps with decreased stride length, rigidity in knees and ankles, shuffling of the feet (39)
Sudden buckling of knees without falling	Intermittent sudden buckling of the knees associated with bracing or activating anti-gravity muscles before touching the ground (39)
Excessive slowness/cautious	Slow motion gait. Slowed speed of every step and may have simultaneous innervation of antagonist muscles and abduction of the arms (39,42)
Dragging of one foot	Monoplegic gait with normal swing phase on the unaffected side. The forefoot of the dragging leg if often kept in contact with the floor in all of the phases of gait cycle. The leg and/or the foot is often externally or medially rotated with clear compensatory effort to propel the leg forwards during swing phase, with an extended hip and/or knee (39,40,43)
Truncal imbalance	Instability of the trunk in stance and gait, with side-to-side swaying and flailing of the arms. Stepping often occurs to correct balance (40,41)
Functional Dystonic gait	Abnormal posturing of the leg or trunk during gait cycle. Fixed plantar flexion and inversion posturing of the foot is often seen. Inconsistencies may include disappearance of abnormal posturing in different positions (41)
Functional Tremulous gait	Gait characterized by tremor in stance or swing phases affecting lower limbs or trunk. Tremor may change in different postures (42,43)
Tightrope walking	Exaggerated truncal sway while maintaining a narrow base, with legs appearing to follow a tightrope, truncal instability with good targeting of nearby walls or furniture (43)
Neurological disease mimics	Camptocormic: Abnormal flexion of the trunk in standing position that worsens during walking (43) Sensory ataxic: Broad-based gait, with feet dropping down clumsily during initial stance. The person tends to look at their feet throughout the gait cycle (43) Choreoballistic: Involuntary flinging of the limbs or trunk, which results in severe, uncontrollable flailing (43) Stiff-man syndrome/robotic: Involuntary activation of axial agonist and antagonistic muscles impacting postural control (43) Ataxic gait: Variability in base of support or inability to walk in a straight line, often with excessive arm movements (41) Spastic (scissoring) gait: Legs cross the midline during swing phase despite no adductor spasticity on testing and normal leg reflexes. Scissoring gait can improve when walking backwards (41,42) Trendelenburg (weak) gait: Inconsistent waddling gait (41) Parkinsonian gait: Bradykinetic gait with inconsistent and distractible freezing, tremor and rigidity (41,42) Hemiparetic gait: Dragging of one leg through the swing phase, variability during gait and no spasticity found on testing. Give-way weakness with positive hoover/abductor sign can be found (41) Footdrop: Dropping of the forefoot at initial swing or mid-swing (43)

Adapted from Lempert et al., 1991 (39), Jordbru et al., 2012 (40), Nonnekes et al., 2020 (41), Fung 2016 (43), Baizabal-Carvallo et al., 2020 (42)

Table 2. Multidisciplinary treatment studies in motor-FND (including FGD).

Trial	Study design	Cohort	Symptom duration	Treatment (type/setting)	Outcome measures	Main outcomes
Petrochilos et al 2020 (64)	Prospective cohort study	Motor-FND n = 78	Mean of 6.5 years	MDT program, day therapy 2 days per week for 5 weeks Individual treatment sessions of CBT (× 9), physiotherapy (× 9), OT (× 9), consultant neuropsychiatry sessions (× 3) and a family session.	PHQ15 PHQ9 GAD7 SPIN RSE HONOS WSAS COPM EQ-5D-5 L CGI	At 6-month review post-program improvements were seen in Somatic symptoms (PHQ15) Depression (PHQ9) Anxiety (GAD7) Health and social functioning (HONOS) Functionality (COPM), health status (EQ-5D-5 L) Patient-rated clinical global improvement (CGI)
Demartini et al 2014 (65)	Prospective cohort study	Motor-FND n = 66	Mean of 4.8 years	4-week specialized inpatient program 5-days per week of therapy input Cognitive behavioral therapy, occupational therapy, physiotherapy and neuropsychiatry	HoNOS COPM FQ PHQ15 CNSQ IPS HADS IPQ-R CGI	At discharge 66.2% patients rated their general health as “better” or “much better” on the CGI and 75.0% rated their main symptoms as “better” or “much better” on the IPS 12-month follow up showed maintained improvements on the CGI
Jordbru et al 2014 (63)	RCT	Exclusively FGD n = 60	Mean of 9 months	3-week inpatient rehabilitation program including adapted physical activity within a cognitive behavioral framework, reinforcing normal gait	FIM FMS SF-12	The mean difference between treatment and no treatment was 6.9 FMS units (p < 0.001, 95% CI 5.5–8.3) The mean difference between treatment and no treatment was 8.4 FIM units (p < 0.001, 95% CI 5.2–11.7) The mean difference in SF-Physical score for treatment vs no treatment was 11.7 units (p < 0.001, 95% CI 7.2–16.1)
Mccormack et al 2013 (66)	Retrospective study	Motor-FND n = 33	Mean of 48 months	Inpatient treatment in a neuropsychiatry unit Input from neuropsychiatrist, psychologist, physiotherapist and occupational therapist individualized to the patients	Mobility ADLs MRS	Data from admission and discharge was extracted and compared The proportion of patients progressing from mobilizing in a wheelchair to unaided or with the aid of a stick/crutches increased from 33.3% (n = 11) to 72.7% (n = 24) The proportion of those who were wheelchair dependent fell from 57.6% (n = 19) to 15.2% (n = 5) Cases also showed a statistically significant improvement in MRS score from admission (mean 3.64, SD 0.86, range 2–5) to discharge (mean 2.82, SD 0.85, range 2–5); p < 0.001.
Czarnecki et al 2012 (67)	Historical-cohort-study	Motor-FND n = 60	Median duration of 17 months	Outpatient, 5-day intensive rehabilitation program based on the concept of motor reprogramming following a comprehensive diagnostic neurological evaluation, including psychiatric/psychological assessment.	Patient- and physician-rated improvements (scale 0–4) Self-rated level of disability	The end-of-treatment rating was classified as markedly improved or completely normal/in remission (“good outcome”) in 73.3% based on physician assessment and 68.8% by patient assessment. Self-assigned level of disability differed significantly between groups (p = 0.019), with 62.4% of treated patients rating their disability level as “mild” or “none,” compared to 43.8% of controls. Follow up at 25 months indicated that 60.4% participants were markedly improved or almost completely normal/in remission, compared to 21.9% of controls (p < 0.001)

MDT: Multidisciplinary team; CBT: Cognitive behavioral therapy; PHQ15: Patient health questionnaire 15; PHQ9: Patient health questionnaire 9; GAD7: Generalized Anxiety Disorder Assessment 7; SPIN: Social Phobia Inventory; RSE: Rosenberg Self-Esteem Scale; HONOS: Health of the Nation Outcome Scales; WSAS: Work and social adjustment scale; COPM: Canadian Occupational Performance Measure; CGI: Clinical global impression scale; FQ: Fear Questionnaire; CNSQ: The Common Neurological Symptom Questionnaire; IPS: Improvement in presenting symptom; HADS: Hospital anxiety and depression scale; IPQ-R: The Revised Illness Perception Questionnaire; FIM: Functional independence measure; FMS: Functional mobility scale; SF-12: 12-Item Short Form Survey; ADLs: Activities of daily living; MRS: Modified Rankin Scale

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