What is the diagnosis and treatment for a patient who experiences a sensation of walking on uneven ground without neuropathy?

Differential Diagnosis: Sensory Ataxia from Large Fiber Neuropathy

The sensation of walking on uneven ground without confirmed neuropathy most likely represents sensory ataxia from large fiber dysfunction affecting proprioception, and requires immediate comprehensive neurological examination with specific focus on vibration sense, proprioception testing, and gait assessment to identify the underlying cause. 1

Key Clinical Features to Assess

The sensation of walking on uneven ground is a classic description of proprioceptive loss affecting large sensory fibers, which can occur even when routine neuropathy screening appears normal. 1

Essential Physical Examination Components

• Vibration testing with 128-Hz tuning fork at the great toe and malleoli to assess large fiber function—this is often the earliest and most sensitive finding 1, 2
• Proprioception testing at the great toe and ankle joints with eyes closed 1
• Romberg test to distinguish sensory from cerebellar ataxia—positive Romberg (worsening with eyes closed) suggests sensory ataxia 1, 3
• Gait assessment including tandem walking, which will be impaired in sensory ataxia 1
• Deep tendon reflexes, particularly ankle reflexes, which may be diminished or absent 1

Critical Diagnostic Considerations

Rule Out Serious Neurological Conditions

Gait and balance impairment can indicate disorders where cognitive, behavioral, and motor dysfunction co-occur, including Parkinson's spectrum disorders (Dementia with Lewy Bodies, Parkinson's disease dementia), vascular cognitive impairment, or frontotemporal lobar degeneration syndromes like progressive supranuclear palsy. 1

Exclude Metabolic and Toxic Causes

Even without diagnosed diabetes, evaluate for:

• Prediabetes or undiagnosed diabetes with fasting glucose and HbA1c 1, 4
• Vitamin B12 deficiency, which causes large fiber neuropathy and is treatable 1, 4
• Medication-induced neuropathy from chemotherapy agents, immunomodulators, or other neurotoxic drugs 5, 6
• Alcohol use as a common cause of large fiber neuropathy 4

Consider Vestibular Dysfunction

While less likely given the specific description, bilateral vestibular hypofunction can present with imbalance that patients describe as walking on uneven surfaces, particularly in low-light conditions. 5

Diagnostic Algorithm

1. Perform comprehensive neurological examination focusing on large fiber function (vibration, proprioception) and gait assessment 1

2. Obtain laboratory studies: fasting glucose, HbA1c, vitamin B12, complete metabolic panel, and thyroid function 1, 4

3. If examination confirms sensory ataxia with large fiber loss:

   • Consider nerve conduction studies and EMG to characterize the neuropathy pattern 1, 3
   • Brain and spine MRI if upper motor neuron signs, cognitive changes, or atypical features suggest central pathology 1, 5

4. If examination is normal but symptoms persist:

   • Refer to neurology for specialized testing including quantitative sensory testing 7
   • Consider autoimmune ataxia workup if family history or other autoimmune features present 5

Management Approach

Immediate Safety Interventions

Fall risk is substantially increased when sensory deficits affect proprioception, even without other neurological impairments. 1

• Home safety assessment including adequate lighting, removal of trip hazards, installation of grab bars, and use of night lights 1
• Assistive devices such as a cane or walker if gait instability is significant 1
• Physical therapy referral for gait training and balance exercises to compensate for proprioceptive loss 1

Disease-Specific Treatment

Treatment depends entirely on the underlying etiology identified through diagnostic workup:

• Vitamin B12 deficiency: replacement therapy can reverse or stabilize neuropathy 1
• Diabetes/prediabetes: aggressive glucose control to prevent progression 1
• Medication-induced: discontinue or substitute offending agent if possible 5, 6

Common Pitfalls to Avoid

• Do not dismiss symptoms because routine diabetic neuropathy screening (10-g monofilament) is normal—monofilament testing assesses small fiber function and loss of protective sensation, not the large fiber proprioceptive dysfunction causing this patient's symptoms 2, 8

• Do not attribute symptoms to aging or deconditioning without thorough evaluation—sensory ataxia always has an identifiable cause that may be treatable 1, 3

• Do not overlook central causes—while peripheral neuropathy is common, the sensation of uneven ground can also result from posterior column dysfunction in the spinal cord or sensory pathway lesions in the brain 1, 5

• Do not delay safety interventions while awaiting diagnostic workup—fall prevention measures should be implemented immediately given the high risk of injury 1