What is the best course of action for a patient with intermittent dizziness, brain fog, and memory issues lasting more than 6 months?

Systematic Diagnostic Workup for Chronic Dizziness, Brain Fog, and Memory Issues

This patient requires a comprehensive dementia evaluation with standard medical workup to identify reversible causes, combined with targeted assessment for vestibular disorders and psychiatric symptoms, particularly depression and anxiety. 1

Initial Diagnostic Framework

The 6-month duration places this patient in the chronic vestibular syndrome category, which has a distinct differential diagnosis from acute or episodic presentations. 1 The combination of dizziness with cognitive symptoms (brain fog, memory issues) significantly broadens the differential and requires parallel evaluation of both vestibular and cognitive domains.

Priority 1: Rule Out Reversible Causes

Obtain corroborative history from a reliable informant regarding changes in cognition, function, and behavior—this is essential and has prognostic significance. 1 Specifically ask about:

• Timing: Whether symptoms are new onset versus chronic/longstanding 1
• Functional decline: Changes in instrumental activities of daily living (IADLs) and basic ADLs 1
• Behavioral changes: New psychiatric symptoms, particularly depression and anxiety 1

Priority 2: Structured Assessment Tools

Use validated scales across multiple domains: 1

Cognitive Assessment:

• Montreal Cognitive Assessment (MoCA) or Clock Drawing Test for objective cognition 1, 2
• Subjective Cognitive Decline Questionnaire (SCD-Q) part 1 for patient self-report 1

Functional Assessment:

• Lawton Instrumental Activities of Daily Living Scale 1
• Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) 1

Psychiatric Screening:

• Geriatric Depression Scale (GDS) or PHQ-9 for depression 1, 2
• GAD-7 for anxiety 1

Laboratory and Imaging Workup

Essential Laboratory Tests

Standard dementia workup to identify reversible causes: 1

• Complete blood count 1
• Comprehensive metabolic panel (glucose, electrolytes, renal function) 1
• Thyroid-stimulating hormone 1
• Vitamin B12 and folate 1
• Inflammatory markers (C-reactive protein) 1

Additional tests based on clinical suspicion:

• Blood alcohol level if substance use suspected 1
• Screening for psychoactive drugs 1

Neuroimaging Indications

MRI head without contrast is indicated if: 1

• Combined neurological symptoms are present (strongest predictor with OR 16.72) 1
• Central oculomotor signs on examination 1
• Focal neurological abnormalities 1
• Rapid cognitive decline or unexpected deterioration 2

Important caveat: CT head has extremely low diagnostic yield (2.2%) for chronic dizziness, while MRI changes diagnosis in 16% of cases. 1 However, MRI can be falsely negative for small posterior fossa strokes within 48 hours, so delayed imaging (3-7 days) may be needed if initial imaging is negative and clinical suspicion remains high. 1

Physical Examination Priorities

Vestibular Assessment

For chronic dizziness, perform: 3, 4

• Orthostatic blood pressure measurement 3, 4
• Assessment for spontaneous nystagmus 3
• Dix-Hallpike maneuver (though less likely positive in chronic presentations) 3
• Full neurologic examination focusing on cerebellar signs 3

Do NOT perform HINTS examination in this chronic presentation—HINTS is specifically for acute vestibular syndrome (symptoms lasting days, not months). 1

Cognitive Examination

Perform focused assessment for: 1

• Memory (immediate and delayed recall)
• Executive function
• Attention and concentration
• Visuospatial abilities

Decision Algorithm Based on Findings

If Corroborative History is NEGATIVE:

• Provide reassurance 1
• Offer follow-up if patient or informant notes future deterioration in cognition, function, or behavior 1
• Consider psychiatric evaluation for anxiety/panic disorder (common cause of chronic dizziness with cognitive complaints) 1

If Corroborative History is POSITIVE:

Immediate actions: 1

1. Schedule annual follow-ups at minimum 1
2. Consider referral to memory clinic for detailed neuropsychological testing 1
3. Proceed with laboratory testing and neuroimaging as outlined above 1

If significant psychiatric symptoms present:

• Refer for psychiatric assessment and/or treatment 1
• Depression and anxiety are both common causes of chronic dizziness AND can mimic or coexist with cognitive impairment 1

If Vascular Risk Factors Present:

Monitor and aggressively manage hypertension and diabetes, as these impact both vestibular function and dementia progression. 2 Patients with vascular risk factors and cognitive decline may represent vascular dementia or mixed dementia. 1

Critical Differential Considerations

Mild Cognitive Impairment vs. Covert Hepatic Encephalopathy

In patients over 60, MCI prevalence reaches 20% and shows significant symptom overlap with other causes of cognitive impairment. 1 Key distinguishing features:

• MCI: Symptoms noticeable for ≥6 months, daily functioning largely preserved, memory often affected 1
• Covert HE: Fluctuating symptoms, attention/concentration deficits, preserved language and memory, motor speed/accuracy affected 1

If plasma ammonia is normal, hepatic encephalopathy is effectively ruled out. 1

Chronic Vestibular Disorders

Common causes in this timeframe include: 1

• Medication side effects (review all medications, especially those with anticholinergic effects) 1
• Anxiety or panic disorder 1
• Post-traumatic vertigo 1
• Cervicogenic vertigo 1

Neuroinflammation ("Brain Fog")

Chronic low-level inflammation can cause subjective cognitive difficulties. 5 Consider evaluation for systemic inflammatory conditions if other causes excluded. 5

Treatment Approach

Do not initiate symptomatic treatment until diagnosis is established. The treatment depends entirely on the underlying etiology:

• If dementia confirmed: Consider cholinesterase inhibitors or memantine per dementia guidelines 1
• If vestibular disorder: Vestibular rehabilitation therapy 3, 4
• If psychiatric: Appropriate psychopharmacology and psychotherapy 1
• If medication-related: Deprescribe offending agents 1

Avoid vestibular suppressants (meclizine, benzodiazepines) in chronic presentations—they impair central compensation and worsen long-term outcomes. 3

Common Pitfalls

1. Assuming symptoms are "just anxiety" without objective cognitive testing and informant input—this misses early dementia in 20-30% of cases 1
2. Ordering CT instead of MRI for chronic neurological symptoms—CT misses the diagnosis 14% of the time compared to MRI 1
3. Failing to obtain informant history—patient self-report of cognitive symptoms has poor correlation with actual impairment 1
4. Not screening for depression—depression causes both dizziness and cognitive complaints and is highly treatable 1