Communicating normal pressure hydrocephalus is a result of an imbalance between cerebral spinal fluid (CSF) production and reabsorption. Some have suggested that the term “normal” pressure hydrocephalus is a misnomer, because intracranial pressure may or may not be normal. This is in contrast to non-communicating, or obstructive hydrocephalus, which may occur when the CSF system is blocked within the ventricles, for example from trauma or a tumor, and intracranial pressure typically increases. Most cases of communicating hydrocephalus observed in older adults are idiopathic. Other causes of NPH include trauma, hemorrhage, infections (e.g. meningitis), and lesions, as these may cause inflammation within the arachnoid space and can interfere with CSF absorption (Pujari et al., 2008; Shprecher et al., 2008). The prevalence rate of idiopathic NPH has been estimated to be 5.5 per 100,000 (Shprecher et al., 2008; Brean & Eide, 2008).
Treatment in the form of CSF shunting procedures has been demonstrated to alleviate some of the symptoms. To predict which patients may have more favorable outcomes following the procedure, high volume CSF removal via lumbar puncture or external lumbar drainage is typically used and may temporarily ameliorate symptoms. Gait (and sometimes cognition) is tested before and after these procedures to determine the likelihood of improvement following the shunting procedure (Shprecher et al., 2008).
Apathy, ventriculomegaly and neurocognitive improvement following shunt surgery in normal pressure hydrocephalus (2015)
Introduction. Apathy – impaired motivation and goal-directed behaviour – is a common yet often overlooked symptom in normal pressure hydrocephalus (NPH). Caudate atrophy often yields apathetic symptoms; however, this structural and functional relationship has not yet been explored in NPH. Additionally, little is known about the relationship between apathy and post-shunt cognitive recovery.
Methods. This audit investigated whether apathetic symptoms improve following shunt surgery in NPH, and whether this relates to cognitive response. In addition, we assessed the relationship between ventriculomegaly and apathy using the bicaudate ratio. Twenty-two patients with NPH completed the Mini-Mental State Examination (MMSE), the Apathy Evaluation Scale (AES) and the Geriatric Depression Scale (GDS) before and 3–9 months after shunt surgery. Pre-operative ventriculomegaly was correlated with pre-operative AES and GDS scores. Difference scores (post-shunt minus baseline values) for AES and GDS were correlated with cognitive outcome.
Results. Greater pre-operative ventriculomegaly was associated with increased level of apathy and depression. A reduction in apathetic symptoms following shunt surgery was associated with improved performance on the MMSE.
Conclusions. Apathy may be indicative of a greater degree of subcortical atrophy in NPH and may relate to functional outcome.
Peterson, K. A., Housden, C. R., Killikelly, C., DeVito, E. E., Keong, N. C., Savulich, G., . . . Sahakian, B. J. (2015). Apathy, ventriculomegaly and neurocognitive improvement following shunt surgery in normal pressure hydrocephalus. British journal of neurosurgery, 1-5. Retrieved From: http://www.tandfonline.com.ezproxy.lib.usf.edu/doi/abs/10.3109/02688697.2015.1029429
Other Media and Resources:
Podcast: Normal Pressure Hydrocephalus: How often does the diagnosis hold water?
Dr. Heather Harle of the American Academy of Neurology (AAN) interviews Dr. Bryan Klassen about his paper on normal pressure hydrocephalus. Paper Citation: Klassen, B. T., & Ahlskog, J. E. (2011). Normal pressure hydrocephalus How often does the diagnosis hold water? Neurology, 77(12), 1119-1125.
Video: Classic NPH Gait Pre-Shunt Surgery; Hydrocephalus Association
Podcast: Practice Guideline: Idiopathic normal pressure hydrocephalus: Response to shunting and predictors of response In the second segment of this podcast, Dr. Farrah Mateen of the American Academy of Neurology interviews Dr. John Halperin about the AAN guideline on response to shunting and predictors of response in idiopathic normal pressure hydrocephalus.
Website: NPH Overview; Columbia University, Department of Neurosurgery
Website: Hydrocephalus Association
Brean, A., & Eide, P. (2008). Prevalence of probable idiopathic normal pressure hydrocephalus in a Norwegian population. Acta Neurologica Scandinavica, 118(1), 48-53. http://www.ncbi.nlm.nih.gov/pubmed/18205881
Hamilton, R., Patel, S., Lee, E. B., Jackson, E. M., Lopinto, J., Arnold, S. E., . . . Xie, S. X. (2010). Lack of shunt response in suspected idiopathic normal pressure hydrocephalus with Alzheimer disease pathology. Annals of Neurology, 68(4), 535-540. http://www.ncbi.nlm.nih.gov/pubmed/20687117
Hellström, P., Edsbagge, M., Archer, T., Tisell, M., Tullberg, M., & Wikkelsø, C. (2007). The neuropsychology of patients with clinically diagnosed idiopathic normal pressure hydrocephalus. Neurosurgery, 61(6), 1219-1228. http://www.ncbi.nlm.nih.gov/pubmed/18162901
Koivisto, A. M., Alafuzoff, I., Savolainen, S., Sutela, A., Rummukainen, J., Kurki, M., . . . Leinonen, V. (2013). Poor cognitive outcome in shunt-responsive idiopathic normal pressure hydrocephalus. Neurosurgery, 72(1), 1-8. http://www.ncbi.nlm.nih.gov/pubmed/23037817
Pujari, S., Kharkar, S., Metellus, P., Shuck, J., Williams, M., & Rigamonti, D. (2008). Normal pressure hydrocephalus: long term outcome after shunt surgery. Journal of Neurology, Neurosurgery, & Psychiatry, 79, 1282-1286. http://jnnp.bmj.com/content/79/11/1282.short
Saito, M., Nishio, Y., Kanno, S., Uchiyama, M., Hayashi, A., Takagi, M., . . . Iizuka, O. (2011). Cognitive profile of idiopathic normal pressure hydrocephalus. Dementia and Geriatric Cognitive Disorders, 1(1), 202-211. http://www.ncbi.nlm.nih.gov/pubmed/22163245
Shprecher, D., Schwalb, J., & Kurlan, R. (2008). Normal pressure hydrocephalus: diagnosis and
treatment. Current Neurology and Neuroscience Reports, 8(5), 371-376.
Solana, E., Poca, M. A., Sahuquillo, J., Benejam, B., Junqué, C., & Dronavalli, M. (2010). Cognitive and
motor improvement after retesting in normal-pressure hydrocephalus: a real change or merely a
learning effect? Clinical article. Journal of Neurosurgery, 112(2), 399-409. http://www.ncbi.nlm.nih.gov/pubmed/19480539
Toma, A. K., Papadopoulos, M. C., Stapleton, S., Kitchen, N. D., & Watkins, L. D. (2013). Systematic review of the outcome of shunt surgery in idiopathic normal-pressure hydrocephalus. Acta Neurochirurgica, 155(10), 1977-1980. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0058973/