50th Anniversary of the Recognition of Normal Pressure Hydrocephalus

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Salomon Hakim, normal pressure hydrocephalus

Dr. Salomon Hakim explaining NPH

By Carlos Hakim, Ph.D., and Marvin Sussman, Ph.D.

Today, March 10, 2014, marks the 50th anniversary of the recognition of Normal Pressure Hydrocephalus (NPH) as a distinct medical syndrome by Salomón Hakim, M.D., Ph.D., with his publication of the first thesis on this condition. NPH is a chronic neurological disorder characterized by an accumulation of cerebrospinal fluid that causes the ventricles in the brain to gradually enlarge, sometimes with little or no increase in intracranial pressure. It is most commonly seen in older adults, and is accompanied by some or all of a triad of symptoms that include gait disturbances, dementia, and impaired bladder control. The current treatment for NPH is the insertion of a shunt into the brain that diverts cerebrospinal fluid (CSF) from the brain to another part of the body where it is absorbed. Dr. Hakim first identified this as a specific syndrome in 1957 at the Hospital San Juan de Dios in Bogotá, Colombia. He spent the next 7 years formulating his hypothesis which was presented in this thesis a half century ago.(1) He later went on, with his son Carlos Hakim, Ph.D., a biomedical engineer and neuroscientist, to design the programmable or adjustable shunt for the treatment of NPH and other forms of hydrocephalus, which still bears his name.

In the 1960s, a treatable form of neurodegeneration or dementia was a controversial claim. Most clinicians did not believe that such conditions could be reversed surgically by diverting excess of CSF in the brains of affected patients using a shunt. Even after many decades of clinical and scientific study on this subject, Dr. Hakim’s story remains largely untold and many people suffering from this condition remain misdiagnosed or undiagnosed by the general medical community.

NPH can occur in adults of any age, but it is primarily associated with older age. This should be of particular concern, considering the large “baby boomer” population has reached the age where the NPH incidence increases. A diagnosis of Alzheimer’s Disease, Parkinson’s Disease or any one of a number of untreatable dementias is devastating to patient and families. Sometimes that diagnosis is wrong or patients may have a significant component due to an NPH comorbidity. When the cause of a significant portion of the patient’s dementia is NPH, it may be treatable if the correct diagnosis is made and the individual is a viable candidate for treatment. Tragically, many thousands of people are misdiagnosed or remain undiagnosed and, therefore, untreated when treatment is possible. Sufferers, often stuck in wheelchairs for years, get up and walk after diagnosis and successful shunting. They literally get their lives back.

Dr. Hakim, whose family name means “doctor” or “wise man” in Arabic, earned his medical degree from the Universidad Nacional in Bogotá and continued his medical education in neurosurgery at Harvard, also earning a Ph.D. in neuropathology. During his neuropathology fellowship research, Dr. Hakim performed autopsies on patients who died from central nervous system (CNS) neurodegenerative conditions, such as Alzheimer’s disease. He noted, in many of the cases, the brain ventricles were enlarged without destruction of the brain cortex. At that time, nobody was able to explain the reason for this observation. This led Dr. Hakim to hypothesize that these patients suffered from what he described as “Normal-Pressure Hydrocephalus” or “NPH,” after finding a 16-year-old living patient with this condition. Dr. Hakim described his discovery in the foreword to the English translation of his 1964 thesis entitled “Some Observations on C. S. F. Pressure. Hydrocephalic Syndrome in Adults with “Normal” C. S. F. Pressure (Recognition of a new syndrome.)” In his own words:

“While searching for a rationale to explain this paradox, a case with hydrocephalus secondary to subarachnoid bleeding was reviewed and speculated upon. Research was conducted into the possible physical principles involved. Then the importance of the area of the ventricles was recognized, and the mechanism of symptomatic hydrocephalus with normal C. S. F. pressure was explained on the basis of increased force due to the pressure-area relationship of the ventricles (F = P x A).*

After a patient was seen with this combination of symptoms and findings but without any history that would account for the hydrocephalus (intracranial hemorrhage, trauma, meningitis, surgery, etc.), a search was begun for the so-called idiopathic cases. These patients are most important and surprising because of the danger that they will be misdiagnosed and placed in a hopeless category (organic brain diseases). It is in the large group of patients with late-life dementia that further cases must be sought . . .”

*Force= Pressure x Area

The publication of Dr. Hakim’s 1964 thesis was followed by the publication of 6 case reports of “normal pressure hydrocephalus” in The New England Journal of Medicine and the Journal of the Neurological Sciences in 1965. (1,2,3)

It is important to understand that today, over 50 years after Dr. Hakim’s discovery, treating NPH is an accepted practice. Diagnosing NPH, however, remains an inexact science and this diagnosis is often missed by clinicians outside of neurosurgery, leaving patients with a treatable dementia locked in a condition from which, with proper treatment, many could be released. To commemorate this landmark year and the work of Dr. Salomón Hakim, the Hydrocephalus Association will host a series of educational blogs about NPH, the current research around the condition, and stories from the patient community. We encourage everyone to share this information with medical professionals, loved ones, and the general public to raise awareness for this often undiagnosed and misdiagnosed condition. Anyone having one or more of three symptoms associated with this syndrome – impaired gate, urinary incontinence or dementia – should be considered for a work up for NPH by a clinician experienced in the diagnosis of this condition. The Hydrocephalus Association maintains a list of neurologists and neurosurgeons experienced with NPH. Please contact us at info@hydroassoc.org for more information or assistance.

Click here to read Dr. Salomon Hakim’s 1964 Thesis.


1. Hakim S. Some observations on CSF pressure. Hydrocephalic syndrome in adults with “normal” CSF pressure (Recognition of a new syndrome). Theses #957 p. 1-40, Javeriana University School of Medicine, Bogota, Colombia, SA, March 10, 1964.

2. Hakim S, Adams RD. The special clinical problem of symptomatic hydrocephalus with normal cerebrospinal fluid pressure. Observations on cerebrospinal fluid hydrodynamics. J Neurol Sci 1965, 2:307-329.

3. Adams RD, Fisher CM, Hakim S, et al. Symptomatic occult hydrocephalus with “normal” cerebrospinal fluid pressure. A treatable syndrome. NEJM 1965, 273:117-126.

1 Comments for : 50th Anniversary of the Recognition of Normal Pressure Hydrocephalus
    • Angela Leone
    • March 22, 2016

    I am trying to find a neurosurgeon in the Va-Md- Washington, D. C. area who deals with NPH. My doctor was Dr. Rigamonti who has been sent by Johns Hopkins to Saudi Arabia. I am having difficulty locating another hydrocephalus surgeon or specialist.

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