Tag: Alzheimer disease

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Poor Cognitive Outcome in Shunt-Responsive Idiopathic Normal Pressure Hydrocephalus

hydrocephalusNeurosurgery 72:1–8, 2013

Idiopathic normal pressure hydrocephalus (iNPH) causes cognitive decline that can be alleviated by shunting, but long-term outcome studies are scarce.

OBJECTIVE: To elucidate the long-term cognitive condition of shunt-responsive iNPH patients.

METHODS: The follow-up data (Kuopio University Hospital NPH Registry) of 146 patients diagnosed with iNPH by clinical and radiological examination, 24-hour intraventricular pressure monitoring, frontal cortical biopsy, and response to the shunt were analyzed for signs of dementia. The Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition, and specified memory disorder criteria were used. Median follow-up was 4.8 years.

RESULTS: At the end of follow-up, 117 (80%) of the 146 iNPH patients had cognitive decline and 67 (46%) had clinical dementia. The most common clinical diagnoses were Alzheimer disease and vascular dementia. In multivariate analysis of the 146 iNPH patients, memory deficit as a first symptom before shunt (odds ratio [OR] 18.3; 95% confidence interval [CI] 1.9–175), male sex (OR 3.29; 95% CI 1.11-9.73), age (OR 1.17 year; 95% CI 1.07-1.28), and follow-up time (OR 1.20 year; 95% CI 1.02-1.40) predicted dementia. Interestingly, 8 (5%) iNPH patients had dementia without any signs of other neurodegenerative diseases in clinical, neuroradiological, or brain biopsy evaluation. These patients initially presented a full triad of symptoms, with gait disturbance being the most frequent initial symptom followed by deterioration in cognition.

CONCLUSION: The novel findings were (a) a significant risk of dementia in iNPH initially responsive to cerebrospinal fluid shunt, (b) cognitive impairment most commonly due to iNPH-related dementia followed by concurrent degenerative brain disease, and (c) a subgroup with dementia related to iNPH without comorbidities.

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Different Patterns of Fornix Damage in Idiopathic Normal Pressure Hydrocephalus and Alzheimer Disease

Am J Neuroradiol 33:274 –79  Feb 2012

The fornix contains efferent fibers of the hippocampus and is in close contact with the corpus callosum. Part of the fornix is directly attached to the corpus callosum, and another part is suspended from the corpus callosum via the septum pellucidum. DTI can be used to evaluate the morphology and microstructural integrity of the fornix. We examined the pattern of fornix damage in patients with iNPH or AD.
MATERIALS AND METHODS: We enrolled 22 patients with iNPH, 20 with AD, and 20 healthy controls. DTI data were obtained. The morphology (volume, length, and mean cross-sectional area) and FA values of the fornix were evaluated by using tract-specific analysis and compared among groups.
RESULTS: The volume, cross-sectional area, and FA value of the fornix were significantly smaller in patients with iNPH than in controls, whereas the length was significantly greater. In patients with AD, the volume, mean cross-sectional area, and FA value of the fornix were significantly smaller than those in controls, whereas the length was not altered. The fornix was significantly longer in patients with iNPH than in patients with AD, whereas the volume and cross-sectional areas were significantly smaller.
CONCLUSIONS: Our results suggest that the different pathogeneses of these diseases lead to fornix damage through different mechanisms: through mechanical stretching due to lateral ventricular enlargement and corpus callosum deformation in patients with iNPH, and through degeneration secondary to hippocampal atrophy in patients with AD.

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