Correlation of right frontal hypoperfusion and urinary dysfunction in iNPH: a SPECT study

Area of Science:

• Neurology
• Urology
• Radiology

Background:

• Idiopathic normal-pressure hydrocephalus (iNPH) is a neurological disorder characterized by gait disturbance, cognitive decline, and urinary dysfunction.
• The exact pathophysiology of urinary dysfunction in iNPH remains incompletely understood.
• Urinary symptoms significantly impact patient quality of life and caregiver burden.

Purpose of the Study:

• To investigate the neuroimaging correlates of urinary dysfunction in iNPH.
• To elucidate the pathophysiology of urinary dysfunction using SPECT and statistical brain mapping.

Main Methods:

• N-isopropyl-p-iodophenylisopropylcarbamoylmethyl (IMP)-SPECT imaging was performed in 97 patients with iNPH.
• Patients were categorized based on the severity of urinary dysfunction using iNPH grading scales.
• Statistical analysis compared tracer uptake between groups with severe versus mild urinary dysfunction.

Main Results:

• A significant reduction in IMP tracer activity was observed in the right-dominant bilateral frontal cortex and left inferior temporal gyrus in patients with severe urinary dysfunction (P < 0.05).
• These findings remained consistent even after excluding patients with significant gait or cognitive impairment.
• This suggests a specific association between frontal hypoperfusion and urinary dysfunction in iNPH.

Conclusions:

• Urinary dysfunction in iNPH is closely associated with hypoperfusion in the right frontal cortex, a key area for micturition control.
• While gait and cognitive issues can contribute to incontinence, a distinct neurogenic mechanism involving frontal lobe dysfunction is implicated.
• Identifying this neurogenic basis is crucial for understanding and managing urinary symptoms in iNPH.