What are the symptoms of Normal Pressure Hydrocephalus (NPH)?

Normal Pressure Hydrocephalus: Clinical Presentation

Normal pressure hydrocephalus presents with a classic triad of gait disturbance, cognitive impairment, and urinary incontinence, with gait abnormalities typically appearing first and serving as the cardinal diagnostic feature. 1, 2, 3

The Classic Triad

Gait Disturbance (Primary Manifestation)

• Gait disorder is the cardinal sign of NPH, occurring in approximately 70% of patients as the presenting symptom 2, 3
• The characteristic gait pattern is hypokinetic, where the feet appear "glued to the floor" or "magnetic" 2, 4
• Patients exhibit shuffling steps, bradykinesia, and may demonstrate balance instability with a tendency to drift 5
• This gait abnormality typically develops early in the disease course, often years before other symptoms become prominent 4, 6

Cognitive Impairment (Later Development)

• Cognitive decline develops later in the disease progression and manifests primarily as frontal lobe dysfunction 7, 3
• Specific deficits include psychomotor slowing, impaired attention, working memory deficits, reduced verbal fluency, and executive dysfunction 7, 3
• Memory lapses occur but are less prominent than in Alzheimer's disease 7
• The cognitive pattern differs from typical Alzheimer's disease, which presents primarily with progressive memory loss without early prominent gait disturbance 3

Urinary Incontinence (Variable Timing)

• Urinary symptoms include urgency, frequency, nocturia, and frank incontinence 4, 5
• Bowel incontinence may also occur but is less common 5, 8
• These symptoms complete the classic triad but may not be present in all patients 1, 9

Critical Diagnostic Context

Temporal Progression

• Patients typically present late in the disease course due to the slow, gradual onset of symptoms 1
• The insidious nature means symptoms may be present for years before diagnosis, with one documented case showing a 4-year delay 4
• Approximately 80% of NPH cases remain unrecognized and untreated, likely due to difficulty distinguishing it from other neurodegenerative disorders 6

Comorbidity Considerations

• Between 20-57% of NPH patients have concurrent Alzheimer's disease or other neurodegenerative conditions 7, 3
• The presence of moderate to severe Alzheimer's disease burden significantly reduces the likelihood of responding to shunt treatment 1
• NPH can result from secondary causes including trauma, intracranial hemorrhage, meningitis, venous sinus thrombosis, or vasculitis 1

Key Distinguishing Features

Differentiation from Other Dementias

• Unlike Alzheimer's disease, NPH presents with early prominent gait disturbance rather than isolated progressive memory loss 3
• Lewy body dementia is distinguished by visual hallucinations, Parkinsonian symptoms, and fluctuating cognition, which are not characteristic of NPH 3
• The combination of all three symptoms (gait, cognition, incontinence) occurring together should raise strong suspicion for NPH 9, 5

Clinical Significance

• NPH affects approximately 3.7% of patients over 65 years of age 1, 3
• NPH represents one of the few potentially reversible causes of dementia, accounting for approximately 6% of all dementias 3, 4
• Without treatment, the spontaneous course ends in dependence on nursing care for the vast majority of patients 6
• With proper diagnosis and CSF diversion (shunting), 70-90% of patients experience clinical improvement 2, 6

Common Diagnostic Pitfalls

• The gradual symptom onset may be mistaken for normal aging processes by healthcare providers 8
• The clinical presentation mimics multiple other neurological disorders, complicating diagnosis 6, 8
• Risk factors such as diabetes and hypertension are common in this population but are not specific diagnostic indicators 4