- Department of Neurological Surgery, University of Miami, Miami, Florida, United States.
- Department of Neurological Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, United States.
Correspondence Address:
Dr. Ricardo J. Komotar, Department of Neurological Surgery, University of Miami, Miami, Florida, United States.
DOI:10.25259/SNI_112_2021
Copyright: © 2021 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.How to cite this article: Annelise Claire Sprau1, Gregory W. Basil1, Karen Eliahu1, Frederic A. Vallejo1, Evan M. Luther1, Jang W. Yoon2, Michael Y. Wang1, Ricardo J. Komotar1. Using smartphone-based accelerometers to gauge postoperative outcomes in patients with NPH: Implications for ambulatory monitoring. 13-Sep-2021;12:464
How to cite this URL: Annelise Claire Sprau1, Gregory W. Basil1, Karen Eliahu1, Frederic A. Vallejo1, Evan M. Luther1, Jang W. Yoon2, Michael Y. Wang1, Ricardo J. Komotar1. Using smartphone-based accelerometers to gauge postoperative outcomes in patients with NPH: Implications for ambulatory monitoring. 13-Sep-2021;12:464. Available from: https://surgicalneurologyint.com/surgicalint-articles/11106/
Abstract
Background: The surgical treatment of normal pressure hydrocephalus (NPH) with shunting remains controversial due to the difficulty in distinguishing such pathology from other neurological conditions that can present similarly. Thus, patients with suspected NPH should be carefully selected for surgical intervention. Historically, clinical improvement has been measured by the use of functional grades, alleviation of symptoms, and/or patient/family-member reported surveys. Such outcome analysis can be subjective, and there is difficulty in quantifying cognition. Thus, a push for a more quantifiable and objective investigation is warranted, especially for patients with idiopathic NPH (INPH), for which the final diagnosis is confirmed with postoperative clinical improvement. We aimed to use Apple Health (Apple Inc., Cupertino, CA) data to approximate physical activity levels before and after shunt placement for NPH as an objective outcome measurement. The patients were contacted and verbally consented to export Apple Health activity data. The patient’s physical activity data were then analyzed. A chart review from the patient’s EMR was performed to understand and better correlate recovery.
Case Description: Our first patient had short-term improvements in activity levels when compared to his preoperative activity. The patient’s activity level subsequently decreased at 6 months and onward. This decline was simultaneous to new-onset lumbar pain. Our second patient experienced sustained improvements in activity levels for 12 months after his operation. His mobility data were in congruence with his subjectively reported improvement in clinical symptoms. He subsequently experienced a late-decline that began at 48-months. His late deterioration was likely confounded by exogenous factors such as further neurodegenerative diseases coupled with old age.
Conclusion: The use of objective activity data offers a number of key benefits in the analysis of shunted patients with NPH/INPH. In this distinctive patient population, detailed functional outcome analysis is imperative because the long-term prognosis can be affected by comorbid factors or life expectancy. The benefits from using smartphone-based accelerometers for objective outcome metrics are abundant and such an application can serve as a clinical aid to better optimize surgical and recovery care.
Keywords: Idiopathic normal pressure hydrocephalus, Normal pressure hydrocephalus, Outcome analysis, Smartphone accelerometer, Ventriculoperitoneal shunt
INTRODUCTION
The term normal pressure hydrocephalus (NPH) was first coined by Adams et al. in 1965 to describe a clinical syndrome defined by the triad of psychomotor retardation, urinary incontinence, and progressive cognitive impairment.[
On the contrary, the gold-standard for treating primary NPH involves the surgical placement of a shunt. Reported outcomes within the pertinent literature suggest that up to 80% of patients with NPH will respond to CSF shunting, versus 37% of patients with INPH.[
To date, the outcome-based literature for postoperative improvement has been distorted by varying definitions of clinical improvement, differences in postoperative follow-up, and the presence of comorbid medical conditions.[
In this case report, we outline the clinical course of two patients with NPH and utilize their Apple Health Data (Apple Inc., Cupertino, CA) for objective postoperative recovery analysis. This is, to the best of our knowledge, the first report of using a smartphone-based accelerometer to approximate physical activity in the pre- and post-operative period for patients with NPH.
MATERIALS AND METHODS
All patients who underwent surgery for NPH between 2013 and 2020 by a single senior cranial surgeon at a large academic center were included in the study. There were no exclusionary criteria. The patients were contacted and verbally consented by a member of our research team through the telephone following our Institutional Review Board protocol.[
CASE REPORTS
Patient 1
A 76-year-old male presented to the emergency room with slowly progressive gait difficulty, motor retardation, and generalized “weakness.” The patient otherwise had no relevant past medical history. Computed tomography (CT) and magnetic resonance imaging were performed which demonstrated prominent lateral ventricles out of proportion to the degree of cortical sulcal markings [
During his 2-week follow-up visit, the patient reported improvement in his gait, cognition, and incontinence. In his 3-month follow-up visit the patient reported episodic low back pain, but his clinical symptoms from the INPH remained stable and his valve setting was therefore left at 2.0. A timeline of the distance and steps walked by the patient over the span of 1 year preoperatively to 1 year postoperatively demonstrated a progressive decline in activity which continued following surgical intervention [
Patient 2
A 70-year-old male presented with a 2-month history of cognitive slowing, bladder dysfunction, and gait imbalance. The patient additionally reported a history of chronic lower back pain, benign prostatic hyperplasia, and a right total knee replacement 8 months prior. After clinical evaluation and CT imaging, he was found to have INPH and was referred for right VP shunt placement [
At his 2-week follow-up visit, the patient self-reported that his walking has improved since surgery. He did report some fatigue but attributed this to his right total knee replacement. He additionally reported an improvement in both urinary continence and cognition. At this time, the Strata valve was dilated to 1.5 in attempt to further symptomatic improvement. During his 1-month postoperative visit, he reported further improvement in walking and urinary incontinence and his valve was therefore left at 1.5. A timeline of the distance and steps walked by the patient over the span of 1 year preoperatively to 1 year postoperatively demonstrated a transient, but significant improvement in activity following surgery which was sustained until approximately week 47, after which patient experienced progressive activity decline [
DISCUSSION
In this case report, we present the clinical course of two patients with INPH who underwent surgical intervention with a shunt placement. We believe this small sample size is likely related to patient demography, for which many patients in our cohort did not own smartphones or had caretakes that had smartphones in their place. Nevertheless, to the best of our knowledge, this is the first report correlating patient with NPH’s daily physical activity extrapolated from an iPhone application to events described in the EMR.
Over the years, there have been numerous reports on patient outcomes following shunting for both NPH and INPH in attempt to clarify the exact criteria for surgical intervention.[
Notably, one of the cardinal features of NPH is gait impairment. There have been few studies investigating the realm of accelerometer-based mobility assessment in surgically treated NPH patients. Gaglani et al. sought to examine the use of commercial activity monitors (i.e. Fitbit Ultra, Nike Fuelband) for postoperative analysis. In their sample population, they compared the step count recorded by activity monitors to and observed step count for a 10-m walking trial.[
Fortunately, the modern smartphone technology enables us to conveniently capture mobility data in an unbiased and retrospective measure (Basil et al., 2021).[
Moreover, practices are presented with unique challenges across many medical fields during the evolving pandemic, forcing numerous institutions to move feasible care to a virtual platform. In our own experiences, outpatient neurosurgery is no exception, and as we increasingly shift toward a telehealth platform. Although the importance of an in-person physical exam cannot be undermined, virtual objective analysis can serve to positively augment telehealth visits.
Patient activity data
Our first patient had marked short-term improvements in activity levels when comparing his activity 2 weeks preoperatively to 2 weeks postoperatively. The patient’s activity level subsequently decreased at 6 months and onward.
This finding is interesting and has numerous potential explanations. These explanations include (1) misdiagnosis, (2) inappropriate shunt settings, (3) additional undiagnosed neurologic pathologies, or (4) natural history of NPH. While an increase in physical activity levels can be correlated with a patient’s surgical benefits, these objective metrics can likewise lend insight into postoperative decline. Our first patient is a perfect example of this capacity. After our patient started reporting episodic back pain, his physical activity began to decline simultaneously. While it is not possible to fully attribute his decline to lumbar pathology, it does suggest the need for further evaluation and potential treatment of this patient to develop a holistic understanding of his condition.
Our second patient experienced sustained improvements in activity levels when comparing his activity 2 weeks preoperatively to 2 weeks, 6 months, and 12 months postoperatively. His mobility data were in congruence with his subjectively reported improvement in clinical symptoms, as correlated through the EMR. He subsequently experienced a late-decline that began at 48-month postoperatively and persisted thereafter. This finding is especially noteworthy as a certain proportion of patients develop a second clinical deterioration after initial improvement in clinical symptoms.[
The use of objective activity data offers a number of key benefits in the postoperative analysis of patients who have underwent shunt placement for NPH/INPH. In this distinctive patient population, detailed functional outcome analysis is imperative because the long-term prognosis of shunting can be affected by comorbid factors or life expectancy. In addition, because “gait dysfunction” is a pier in the clinical triad of NPH/INPH, objective movement analysis can lend insight to clinical improvement and aid in clinician’s’ management of shunt settings.[
Given the novelty of objective, smartphone-based activity assessment, further research will be required to fully validate these methods. First, there will undoubtedly be questions regarding the accuracy and fidelity of smartphone-based accelerometer data. Fortunately, there are previous studies which address this question.[
While a formal survey was not performed for this particular study, both patients who participated reported that they were typically in possession of their phones.
CONCLUSION
The pertinent literature demonstrates that placing a shunt as a treatment for NPH/INPH may yield varied results. Historically, postoperative outcomes are reported utilizing survey metrics which may be subjective, and often confounded by other co-existing medical conditions in this specific patient population. Ultimately, this calls for an objective outcome metric to augment clinical evaluation in the postoperative period. Our experience with utilizing smartphone accelerometer data from this report suggests short-term and long-term evaluation in activity levels can be used in conjunction with the EMR to better approximate surgical success and guide in postoperative care.
Declaration of patient consent
Patient’s consent not required as patients identity is not disclosed or compromised.
Financial support and sponsorship
Nil.
Conflicts of interest
Dr. Gregory Basil: Co-founder and direct stock ownership in Kinesiometrics LLC Dr. Jang Yoon: Co-founder and direct stock ownership in Kinesiometrics LLC and Medcyclops LLC Dr. Michael Wang: Consultant for DePuy Synthes Spine, K2M, Stryker, and Spineology; patent holder with DePuy Synthes Spine; direct stock ownership in ISD, Medical Device Partners. Co-founder and direct stock ownership in Kinesimoetrics LLC.
Declaration of patient consent
Patient’s consent not required as patients identity is not disclosed or compromised.
Financial support and sponsorship
Nil.
Conflicts of interest
Dr. Gregory Basil: Co-founder and direct stock ownership in Kinesiometrics LLC Dr. Jang Yoon: Co-founder and direct stock ownership in Kinesiometrics LLC and Medcyclops LLC Dr. Michael Wang: Consultant for DePuy Synthes Spine, K2M, Stryker, and Spineology; patent holder with DePuy Synthes Spine; direct stock ownership in ISD, Medical Device Partners. Co-founder and direct stock ownership in Kinesimoetrics LLC.
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