Clinical short communication| Volume 395, P164-168, December 15, 2018

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Idiopathic normal-pressure hydrocephalus and obstructive sleep apnea are frequently associated: A prospective cohort study

  • Gustavo C. Román
    Corresponding author at: Department of Neurology, Methodist Neurological Institute, 6560 Fannin St., Suite # 802, Houston, TX 77030, USA.
    Department of Neurology, Methodist Neurological Institute and Houston Methodist Hospital Research Institute for Academic Medicine, Houston, TX, USA

    Department of Neurology, Weill Cornell Medical College, Cornell University, New York, NY, USA
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  • Aparajitha K. Verma
    Department of Neurology, Methodist Neurological Institute and Houston Methodist Hospital Research Institute for Academic Medicine, Houston, TX, USA

    Sleep Laboratory Houston Methodist Hospital, Houston, TX, USA
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  • Y. Jonathan Zhang
    Department of Neurosurgery, Methodist Neurological Institute and Houston Methodist Hospital Research Institute for Academic Medicine, Houston, TX, USA

    Department of Neurosurgery, Weill Cornell Medical College, Cornell University, New York, NY, USA
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  • Steve H. Fung
    Department of Radiology MRI Core, Houston Methodist Hospital and Methodist Research Institute for Academic Medicine, Houston, TX, USA

    Department of Radiology, Weill Cornell Medical College, Cornell University, New York, NY, USA.
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Published:October 03, 2018DOI:


      • Multiple vascular risk factors (VRFs) often occur in idiopathic normal-pressure hydrocephalus (iNPH).
      • Obstructive sleep apnea (OSA) is an independent vascular risk factor rarely reported in iNPH.
      • Sleep was studied in a prospective cohort of 31 consecutive patients with iNPH from a single memory clinic.
      • Nocturnal polysomnogram confirmed OSA in 90·3% (28/31) patients with iNPH; all had undiagnosed sleep abnormalities and excessive daytime sleepiness.
      • Larger confirmatory studies are needed but it appears reasonable to obtain a sleep history in patients suspected of iNPH.



      Idiopathic normal-pressure hydrocephalus (iNPH) is defined by ventriculomegaly, cognitive decline, urinary incontinence and gait problems. Vascular risk factors (VRF) are associated with iNPH but obstructive sleep apnea (OSA) —a well-known independent VRF— is seldom mentioned.


      We investigated the presence of sleep-disordered breathing in a prospective cohort of 31 consecutive unselected patients with iNPH using sleep questionnaires and nocturnal polysomnography (PSG).


      We found OSA in 90·3% (28/31) patients with iNPH; all had undiagnosed sleep abnormalities (snoring, awakenings, nocturia) and excessive daytime sleepiness (Epworth scale = 11·4 ± 6·4; normal <8). Nocturnal PSG showed moderate-to-severe OSA in 25 patients (80·6%) with mean apnea-hypopnea index (AHI) 31·6 ± 23·6/h; mean respiratory distress index (RDI) 34·5/h; and, mean SaO2 desaturation at nadir, 82·2 ± 7·5%. The observed OSA prevalence is statistically significant: 90·3%, 95%CI 74·3–97·5; p = 0·000007. Other VRF included overweight body-mass index (BMI >25- < 30 kg/m2) in 59%, hyperhomocysteinemia 57%, hypertension 43%, hyperlipidemia 39%, diabetes 32%, smoking 21%, coronary disease 18%, and previous stroke 10%.


      Abnormal sleep breathing is frequently associated with iNPH. Validation in larger series is required but we suggest including sleep evaluation in patients suspected of iNPH.


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