Challenges in diagnosing normal pressure hydrocephalus: Evaluation of the diagnostic guidelines

- Normal pressure hydrocephalus lacks common, standardized diagnostic criteria.
- Considerable discrepancies were found between the two current international guidelines.
- The highest concordance in diagnoses was between the Japanese guidelines and a neurologist.
- We suggest a revision of the current guidelines into one common diagnostic system.

PurposeTo evaluate the present diagnostic guidelines of idiopathic normal pressure hydrocephalus (iNPH) in a sample from the general population.MethodsA total of 168 individuals (93 females, 75 males), mean age 75 years (range 66-92) with and without symptoms of iNPH underwent a CT-scan of the brain, a neurological examination with assessment of the triad symptoms, i.e. gait disturbances, memory impairment and urgency incontinence. The participants were then diagnosed as “unlikely”, “possible” and “probable” iNPH according to the American-European and the Japanese guidelines, respectively. Separately, a senior consultant in neurology diagnosed each patient based on the overall clinical picture.ResultsObtaining a diagnosis of “probable iNPH” was three times more likely according to the American-European guidelines (n = 35) compared to the Japanese guidelines (n = 11) or the neurologist (n = 11). The concordance was highest (Kappa = 0.69) between the Japanese guidelines and the neurologist.ConclusionsConsiderable discrepancies were found when diagnosing iNPH according to two international guidelines and a neurologist, respectively. The Japanese guidelines, which include a minimum of two triad symptoms, were most concordant with the neurologist. As a step towards widely accepted, standardized diagnostic criteria, we suggest a revision of the current guidelines, preferably into one common diagnostic system.