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Quality-of-Life Assessment in Patients Treated with Vagus Nerve Stimulation

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  • BRIEF COMMUNICATION

    Qua tiewith

    Erhanand JeDepartme915 Cami

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    patieIE-10ry, leocialfore a

    6 months, and 912 months after the initiation of VNS in 17 patients. QOLIE-10 scores were signifi-cantly better after the initiation of the therapy as compared with baseline (P < 0.01). There was nocorrelation between the improvement in QOLIE-10 scores and the reduction in seizure frequency,

    INTRO

    Vagustherapyfocal-onshown tquencyepilepticfrequenwith epreceivement anperceivestudiestic treat

    1 To wh6692. E-m

    Epilepsy & Behavior 2, 284287 (2001)

    doi:10.1006/ebeh.2001.0173, available online at http://www.idealibrary.com ondecreased severity of seizures, or increased level of energy/alertness. We conclude that VNS therapyis associated with a significant improvement in subjective quality of life. 2001 Academic Press

    Key Words: vagus nerve stimulation; quality of life; refractory epilepsy.

    DUCTION

    nerve stimulation (VNS) is a novel adjunctiveused in patients with medically intractable,

    set epilepsy (13). Previous studies havehat VNS induces a reduction in seizure fre-comparable to that produced by major anti-drugs (1, 3). Besides the reduction in seizure

    cy, an important consideration for patientsilepsy is the overall effect of treatments theyon the quality of their lives. Hence, the assess-d monitoring of changes in quality of life asd by patients have been part of many clinical

    evaluating the effectiveness of new antiepilep-ments (4, 5).

    The purpose of the present prospective study was toinvestigate if VNS therapy produced subjective im-provements in quality of life in patients with epilepsyrefractory to pharmacological treatments. Preliminaryresults from this study have been published in abstractform (6).

    METHODS

    Seventeen patients (6 female, 11 male) with partial-onset epilepsy were studied in a prospective fashion.The average patient age was 33.8 years (range, 1155years). All patients had persistent, frequent seizuresdespite appropriate medical management. They werenot candidates for surgical treatment either because ofa documented bilaterally independent onset of sei-zures from two hemispheres or because they were notinterested in surgical treatment. The etiologies of sei-

    om correspondence should be addressed. Fax: (505) 272-ail: JShih@salud.unm.edu.

    1525-5050/01 $35.00Copyright 2001 by Academic Presslity-of-Life Assessment in PaVagus Nerve Stimulation

    Ergene, M.D., Pamela K. Behr, R.N.,rry J. Shih, M.D.1

    nt of Neurology, University of New Mexico School of Medicine,no De Salud NE, Albuquerque, New Mexico 87131-5281

    December 1, 2000; revised February 26, 2001;for publication March 5, 2001

    Vagus nerve stimulation (VNS) is a novel therapy used inWe administered a Quality of Life in Epilepsy10 (QOLdesigned to assess the patients rating of their memoenergy, depression, worries about seizures and work, sVNS treatment. The questionnaire was administered be284nts Treated

    nts with medically intractable epilepsy.) questionnaire consisting of questionsvel of physical and mental well-being,limitations, and overall quality of life onnd at 13 weeks, 57 weeks, 3 months,All rights of reproduction in any form reserved.

  • zures in study patients included cerebral palsy/peri-natal brain injury in 5 patients, mesial temporal scle-rosis in 3, traumatic brain injury in 2, subarachnoidhemorrhage due to aneurysm in 1, cavernous angio-mas in 1, and a history of meningitis during infancy in1. The cAll pati

    Priortion of tto a quetory10tive quaal. (7), cpatientsphysicalworriesand ovenaire isreceivesthe ques

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    285Brief Communicationause of seizures was unknown in 4 patients.ents agreed to be treated with VNS.to implantation of the VNS device and initia-reatment, the patients were asked to respondstionnaire, Quality of Life in Epilepsy Inven-

    (QOLIE-10), to assess their baseline subjec-lity of life. QOLIE-10, developed by Cramer etonsists of 10 questions designed to assess the subjective rating of their memory, level of

    and mental well-being, energy, depression,about seizures and work, social limitations,rall quality of life. Each item in the question-ranked on a scale of 1 to 5, and the patienta total scale score of 10 to 50 by answering alltions.

    o three weeks after the initial administration of10, a VNS device was surgically implanted innts. The device was turned on 2 weeks afteration. Standard stimulation parameters ofignal frequency, 500-ms pulse width, 30 s of, and 5 min of off-time were used. The stimu-tensity was initially set at 0.25 mA, and grad-creased to tolerance over a 2- to 3-month pe-th a final value of 1.0 to 2.5 mA in all patients.the baseline assessment, QOLIE-10 was againtered at 13 weeks, 57 weeks, 3 months, 6and 912 months after the initiation of VNS.ition, during each follow-up visit, the patients

    ked if there were any changes in seizure fre-severity, and/or level of energy and alertnessg seizures. The answers to each of these ques-each patient were noted as increased, de-

    or no change. The presence of any sideor subjective complaints attributable to the

    t was also noted. All patients were on stablef two or three antiepileptic drugs (AEDs)out the study.QOLIE-10 score at each time point followingation of VNS treatment for each patient wasd with the baseline QOLIE-10 score of thetient prior to the initiation of treatment. Forssment of statistically significant changes in

    ores across time, a one-way analysis of vari-OVA) for repeated measures was performed.

    ion, QOLIE-10 scores were compared, usingVA of contrast variables, in patients with and

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    FIGQOscaat a(Pdecreased seizure frequency, severity, andd level of energy. A two-tailed P value wasdetermine statistical significance.

    TS

    QOLIE-10 scores were significantly improvedotal QOLIE-10 scale scores) at all time points

    initiation of VNS therapy as compared withbaseline (P , 0.01) throughout the study ofuration. These results are graphically illus-Fig. 1.6-month follow-up visit, 53% of patients re-notable decrease in their seizure frequency

    n VNS treatment. In addition, 59% of pa-perienced a decrease in severity of seizuresss of change in frequency. Twenty-nine per-

    patients felt an increased level of energy ands. Various effects of VNS therapy are sum-

    in Table 1. An analysis of the interactionQOLIE-10 scores and the reduction in seizure

    cy, seizure severity, and increased level ofalertness showed that there was no correla-

    een the improved QOLIE-10 scores and theses.ffects from VNS were minimal, and included/spasm in throat in 4 patients, difficultyg in 1 patient, difficulty speaking in 1 patient,ic discomfort in 1 patient, and increased snor-patient.

    mprovement in QOLIE-10 scores over time. Maximumscore is 50 (worst). ANOVA indicated that the mean totals were significantly better (lower QOLIE-10, total scores)points after the initiation of the therapy than baseline

    ). Bars: 6SEM.

    Copyright 2001 by Academic PressAll rights of reproduction in any form reserved.

  • DISCU

    The amedicalin previtherapypatientssults corbased oscale, hbeing inhave rep(8), andety in p

    We rebrief offiwas notfor QOLaddressinstrumswer twprovemplantati

    Based on our results, the answers are affirmative. Thesignificantly improved subjective quality of life in thepresent study may have been related to physiologicalchanges induced by VNS, minimal side effects fromthe treatment, or even the effect of having a device

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    TABLE 1

    Effects of VNS Therapy on Seizure Frequency, Severity,and Level of Energy/Alertness

    PatientNo.

    Decreasedseizure

    Decreasedseizure

    Increased levelof energy/

    123456789

    1011121314151617

    Total n (%

    a 1 andtively, basfollow-up

    286 Ergene, Behr, and Shih

    Copyright 2All rights of rSSION

    nticonvulsant effect of VNS in patients withly intractable epilepsy has been documentedous studies (1, 2). Our results show that VNSmay also improve overall quality of life inwith medically refractory epilepsy. These re-roborate the results of a previous study that,n a single-question, subject-rated well-beingas shown an improved perception of well-

    VNS patients (7). In addition, recent studiesorted that VNS enhances recognition memorydecreases symptoms of depression and anxi-

    atients with epilepsy (9, 10).cognize this is an uncontrolled study using ace-based QOLIE-10 questionnaire. This studydesigned to determine the etiology or reasonsimprovement, nor does it have the power tomore specific QOL issues present in other

    ents such as the QOLIE-89. We set out to an-o questions: Do patients experience an im-

    ent in subjective quality of life after VNS im-on? Do QOL improvements persist over time?

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