What conditions is gait apraxia typically seen in?

Gait Apraxia: Associated Conditions and Clinical Implications

Gait apraxia is most commonly seen in normal pressure hydrocephalus (NPH), frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), and corticobasal syndrome, with less frequent associations in multiple sclerosis and stroke. 1, 2, 3, 4

Definition and Characteristics

Gait apraxia is a higher-order motor deficit characterized by:

• Difficulty initiating walking (ignition failure)
• Freezing of gait
• Inability to perform purposeful walking movements despite preserved motor strength
• Broad-based, irregular stepping pattern
• Variable step length and lateral veering
• Difficulty with turning

This disorder represents a disconnection between intact motor function and the ability to execute the complex motor program required for walking 1, 2.

Primary Associated Conditions

1. Normal Pressure Hydrocephalus (NPH)

• Part of Hakim's triad: gait apraxia, urinary incontinence, and dementia
• Classic imaging findings include ventriculomegaly, narrowed posterior callosal angle, effaced high convexity sulci, and widened sylvian fissures 1
• Potentially reversible with CSF diversion (shunting) 2, 3

2. Frontotemporal Dementia (FTD) Spectrum

• Seen in 25-80% of FTD patients 1
• Often presents with bradykinesia/akinesia, parkinsonian gait/posture, and rigidity
• May be an early sign in behavioral variant FTD (bvFTD) 1

3. Progressive Supranuclear Palsy (PSP)

• Characterized by lurching gait, unexplained falls, and axial dystonia
• Often presents with vertical supranuclear gaze palsy (later in disease)
• Imaging shows midbrain atrophy ("hummingbird sign"), dilated aqueduct of Sylvius, and frontal lobe atrophy 4

4. Corticobasal Syndrome

• Presents with asymmetric limb rigidity and dystonia
• Associated with ideomotor apraxia and alien limb phenomenon
• Unilateral dystonia and stimulus-sensitive myoclonus may be present 1

5. Multiple Sclerosis (MS)

• Gait apraxia can occur in MS (particularly progressive forms)
• Often develops after median 8 years from disease onset
• Associated with cognitive dysfunction (73%) and neurogenic bladder (93%)
• MRI shows confluent periventricular T2 lesions, T1 hypointensity, and cerebral atrophy 5

6. Stroke

• Particularly affects frontal lobe regions involved in motor planning
• Can occur following right-sided cerebrovascular accidents 6

Diagnostic Approach

1. Neurological Examination:

   • Assess for parkinsonism: bradykinesia, rigidity, tremor
   • Test smooth pursuit and saccadic eye movements (vertical gaze palsy)
   • Evaluate for motor neuron signs and primitive reflexes
   • Test for unilateral dystonia, myoclonus, and alien limb phenomenon 1

2. Cognitive Assessment:

   • Montreal Cognitive Assessment (MoCA) is preferred over MMSE for detecting executive dysfunction 1
   • Evaluate for behavioral changes and dementia

3. Imaging:

   • MRI brain is the preferred modality to evaluate for:

     • Ventriculomegaly and periventricular white matter changes (NPH)
     • Midbrain atrophy (PSP)
     • Asymmetric cortical atrophy (corticobasal syndrome)
     • Cerebellar atrophy (spinocerebellar ataxias)
     • Frontal lobe atrophy (FTD) 1

   • CT head can identify ventriculomegaly in NPH but has limited soft-tissue characterization 1

Management Approaches

Management depends on the underlying etiology:

1. For NPH:

   • CSF diversion via shunting can improve gait in appropriate candidates
   • Serial lumbar punctures may help identify shunt-responsive patients 3

2. For Neurodegenerative Causes (PSP, FTD, Corticobasal Syndrome):

   • Physical therapy focusing on:
     • Visual cues (e.g., fluorescent markers to step over)
     • Reducing movement complexity
     • Encouraging slower movements limited to single joints
     • Stabilizing against inertial effects of limb movement 6

3. For MS-Related Gait Apraxia:

   • Disease-modifying therapies for underlying MS
   • Symptomatic management of spasticity and ataxia 5

4. For Stroke-Related Gait Apraxia:

   • Modified canes with visual cues (e.g., horizontal fluorescent projections)
   • Focused rehabilitation using visual feedback 6

Clinical Pearls and Pitfalls

• Pearl: Gait apraxia that improves after CSF removal strongly suggests NPH as the underlying cause 3
• Pearl: Early vertical gaze abnormalities (slowing of downward saccades) may precede full vertical gaze palsy in PSP 1
• Pitfall: Attributing gait disorders in MS solely to spasticity or ataxia may lead to underrecognition of gait apraxia 5
• Pitfall: Failing to distinguish between true gait apraxia and other causes of gait disturbance (e.g., cerebellar ataxia, sensory ataxia, vestibular ataxia) 7

By recognizing gait apraxia and its associated conditions early, clinicians can better direct diagnostic workup and implement appropriate management strategies to improve patient outcomes and quality of life.