<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v2.0 20040830//EN" "journalpublishing.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="2.0" xml:lang="en" article-type="letter"><front><journal-meta><journal-id journal-id-type="nlm-ta">JMIR Rehabil Assist Technol</journal-id><journal-id journal-id-type="publisher-id">rehab</journal-id><journal-id journal-id-type="index">17</journal-id><journal-title>JMIR Rehabilitation and Assistive Technologies</journal-title><abbrev-journal-title>JMIR Rehabil Assist Technol</abbrev-journal-title><issn pub-type="epub">2369-2529</issn><publisher><publisher-name>JMIR Publications</publisher-name><publisher-loc>Toronto, Canada</publisher-loc></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">v13i1e109396</article-id><article-id pub-id-type="doi">10.2196/109396</article-id><article-categories><subj-group subj-group-type="heading"><subject>Letter to the Editor</subject></subj-group></article-categories><title-group><article-title>Clarifying Methodological Principles and Preliminary Trends in Digital Vestibular Rehabilitation: Authors&#x2019; Reply</article-title></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name name-style="western"><surname>Kaplan</surname><given-names>Azriel</given-names></name><degrees>MSc, PT</degrees><xref ref-type="aff" rid="aff1">1</xref></contrib><contrib contrib-type="author"><name name-style="western"><surname>Kalderon</surname><given-names>Liran</given-names></name><degrees>PT, PhD</degrees><xref ref-type="aff" rid="aff1">1</xref></contrib><contrib contrib-type="author"><name name-style="western"><surname>Wolfovitz</surname><given-names>Amit</given-names></name><degrees>MD</degrees><xref ref-type="aff" rid="aff2">2</xref></contrib><contrib contrib-type="author" equal-contrib="yes"><name name-style="western"><surname>Gimmon</surname><given-names>Yoav</given-names></name><degrees>PT, PhD</degrees><xref ref-type="aff" rid="aff2">2</xref><xref ref-type="aff" rid="aff3">3</xref><xref ref-type="fn" rid="equal-contrib1">*</xref></contrib><contrib contrib-type="author" equal-contrib="yes"><name name-style="western"><surname>Levy-Tzedek</surname><given-names>Shelly</given-names></name><degrees>PhD</degrees><xref ref-type="aff" rid="aff1">1</xref><xref ref-type="aff" rid="aff4">4</xref><xref ref-type="aff" rid="aff5">5</xref><xref ref-type="fn" rid="equal-contrib1">*</xref></contrib></contrib-group><aff id="aff1"><institution>Department of Physical Therapy, Recanati School for Community Health Professions, Ben-Gurion University of the Negev</institution><addr-line>David Ben-Gurion Blvd 1</addr-line><addr-line>Beer-Sheva</addr-line><addr-line>Southern District</addr-line><country>Israel</country></aff><aff id="aff2"><institution>Department of Otolaryngology&#x2014;Head and Neck Surgery, Sheba Medical Center</institution><addr-line>Ramat Gan</addr-line><addr-line>Tel Aviv</addr-line><country>Israel</country></aff><aff id="aff3"><institution>Department of Physical Therapy, Faculty of Social Welfare &#x0026; Health Sciences, University of Haifa</institution><addr-line>Haifa</addr-line><addr-line>Haifa</addr-line><country>Israel</country></aff><aff id="aff4"><institution>Zelman Center for Neuroscience, Ben-Gurion University of the Negev</institution><addr-line>Beer-Sheva</addr-line><addr-line>Southern District</addr-line><country>Israel</country></aff><aff id="aff5"><institution>Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg</institution><addr-line>Freiburg</addr-line><addr-line>Baden-Wurttemberg</addr-line><country>Germany</country></aff><contrib-group><contrib contrib-type="editor"><name name-style="western"><surname>Sarvestan</surname><given-names>Javad</given-names></name></contrib></contrib-group><author-notes><corresp>Correspondence to Azriel Kaplan, MSc, PT, Department of Physical Therapy, Recanati School for Community Health Professions, Ben-Gurion University of the Negev, David Ben-Gurion Blvd 1, Beer-Sheva, Southern District, 8410501, Israel, 972 86479563; <email>azrielk@post.bgu.ac.il</email></corresp><fn fn-type="equal" id="equal-contrib1"><label>*</label><p>these authors contributed equally</p></fn></author-notes><pub-date pub-type="collection"><year>2026</year></pub-date><pub-date pub-type="epub"><day>30</day><month>9</month><year>2026</year></pub-date><volume>13</volume><elocation-id>e109396</elocation-id><history><date date-type="received"><day>12</day><month>08</month><year>2026</year></date><date date-type="rev-recd"><day>14</day><month>08</month><year>2026</year></date><date date-type="accepted"><day>15</day><month>09</month><year>2026</year></date></history><copyright-statement>&#x00A9; Azriel Kaplan, Liran Kalderon, Amit Wolfovitz, Yoav Gimmon, Shelly Levy-Tzedek. Originally published in JMIR Rehabilitation and Assistive Technology (<ext-link ext-link-type="uri" xlink:href="https://rehab.jmir.org">https://rehab.jmir.org</ext-link>), 30.9.2026. </copyright-statement><copyright-year>2026</copyright-year><license license-type="open-access" xlink:href="https://creativecommons.org/licenses/by/4.0/"><p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (<ext-link ext-link-type="uri" xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link>), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Rehabilitation and Assistive Technology, is properly cited. The complete bibliographic information, a link to the original publication on <ext-link ext-link-type="uri" xlink:href="https://rehab.jmir.org/">https://rehab.jmir.org/</ext-link>, as well as this copyright and license information must be included.</p></license><self-uri xlink:type="simple" xlink:href="https://rehab.jmir.org/2026/1/e109396"/><related-article related-article-type="commentary article" ext-link-type="doi" xlink:href="10.2196/e84207" xlink:title="Comment on" xlink:type="simple">https://rehab.jmir.org/2026/1/e84207</related-article><related-article related-article-type="commentary article" ext-link-type="doi" xlink:href="10.2196/e107851" xlink:title="Comment on" xlink:type="simple">https://rehab.jmir.org/2026/1/e107851</related-article><kwd-group><kwd>vestibular rehabilitation</kwd><kwd>smartphone</kwd><kwd>crossover trial</kwd><kwd>digital health</kwd><kwd>statistical analysis</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>To the Editor</title><p>We welcome the commentary [<xref ref-type="bibr" rid="ref1">1</xref>] regarding our publication [<xref ref-type="bibr" rid="ref2">2</xref>] evaluating the Vestibulon app in vestibular rehabilitation. We appreciate the opportunity to clarify the clinical and statistical considerations guiding our pilot trial and to contextualize our findings.</p><p>The author raises a concern regarding the absence of a washout period. The absence of a washout period was a deliberate clinical decision. Vestibular rehabilitation involves central compensation, adaptation, habituation, and motor learning, which may not be reliably reversed by a short interruption. Because participants were symptomatic and receiving clinically indicated care, continuity of rehabilitation was prioritized. We nevertheless acknowledge that carryover from the first period may have limited the interpretation of period-2 comparisons, as noted in our Limitations section [<xref ref-type="bibr" rid="ref2">2</xref>].</p><p>Given the pilot nature of the study and the small sample size, we used prespecified nonparametric methods for the exploratory comparisons. This approach was appropriate for the bounded and potentially skewed Dizziness Handicap Inventory (DHI) and State-Trait Anxiety Inventory scores, which derive from ordinal response categories, and was applied consistently to the continuous Instrumented Timed Up and Go (iTUG) measure. We acknowledge that these tests do not constitute a complete crossover analysis accounting for treatment, period, sequence, within-participant correlation, and potential carryover. This exploratory analysis was not intended to provide definitive evidence of the app&#x2019;s efficacy, but rather to provide initial clinical insights and establish feasibility for future studies.</p><p>Across all sections, we explicitly refrained from making definitive claims of superiority, including regarding early iTUG changes, repeatedly framing results as &#x201C;preliminary trends.&#x201D; Importantly, our Limitations section explicitly outlined the constraints noted by the author: the pilot sample size, potential carryover effects due to the absence of a washout period, and the essential need for a future fully powered randomized controlled trial (RCT).</p><p>We thank the author for identifying the typographical error on page 9, where <italic>P</italic>=.057 was inadvertently reported twice. This <italic>P</italic> value (.057) corresponds to the 2-sided Fisher exact test for the week 6 comparison of 7 of 9 versus 2 of 8 minimal clinically important difference (MCID) responders. Furthermore, for period-specific responder outcomes (6/17 versus 3/17), a valid paired analysis relied on discordant pairs, with 5 participants achieving the MCID strictly during the app period and 2 strictly during the conventional period (exact McNemar test: <italic>P</italic>=.453). Therefore, they should not be analyzed as independent samples alone. As a supplementary analysis less affected by carryover, we analyzed period 1 using an analysis of covariance. Baseline-adjusted week 1 DHI scores were 38.82 in the app-first group and 40.33 in the conventional-first group, a difference that was not statistically significant (<italic>F</italic>=0.04, <italic>P</italic>=.840, partial &#x03B7;<sup>2</sup>=.002). The DHI MCID was achieved by 5 of 9 versus 1 of 8 eligible participants (55.6% vs 12.5%; <italic>P</italic>=.131). Although exploratory for definitive inference, these findings provide a useful trend and preliminary data for an RCT.</p><p>In conclusion, our pilot trial supports the feasibility of integrating smartphone support into vestibular rehabilitation and observed improvement in functional outcomes over the 6-week rehabilitation program. We agree that establishing definitive incremental efficacy requires a parallel-group RCT, and we thank the author for this constructive scientific dialogue.</p></sec></body><back><notes><sec><title>Funding</title><p>The authors declared no financial support was received for this work.</p></sec></notes><fn-group><fn fn-type="conflict"><p>None declared.</p></fn></fn-group><glossary><title>Abbreviations</title><def-list><def-item><term id="abb1">DHI</term><def><p>Dizziness Handicap Inventory</p></def></def-item><def-item><term id="abb2">iTUG</term><def><p>Instrumented Timed Up and Go</p></def></def-item><def-item><term id="abb3">MCID</term><def><p>minimal clinically important difference</p></def></def-item><def-item><term id="abb4">RCT</term><def><p>randomized controlled trial</p></def></def-item></def-list></glossary><ref-list><title>References</title><ref id="ref1"><label>1</label><nlm-citation citation-type="journal"><person-group person-group-type="author"><name name-style="western"><surname>Yan</surname><given-names>J</given-names> </name><name name-style="western"><surname>Yang</surname><given-names>K</given-names> </name><name name-style="western"><surname>Wang</surname><given-names>X</given-names> </name><name name-style="western"><surname>Su</surname><given-names>B</given-names> </name></person-group><article-title>Crossover analysis is needed in smartphone-supported vestibular rehabilitation</article-title><source>JMIR Rehabil Assist Technol</source><year>2026</year><volume>13</volume><fpage>e107851</fpage><pub-id pub-id-type="doi">10.2196/107851</pub-id></nlm-citation></ref><ref id="ref2"><label>2</label><nlm-citation citation-type="journal"><person-group person-group-type="author"><name name-style="western"><surname>Kaplan</surname><given-names>A</given-names> </name><name name-style="western"><surname>Kalderon</surname><given-names>L</given-names> </name><name name-style="western"><surname>Wolfovitz</surname><given-names>A</given-names> </name><name name-style="western"><surname>Gimmon</surname><given-names>Y</given-names> </name><name name-style="western"><surname>Levy-Tzedek</surname><given-names>S</given-names> </name></person-group><article-title>Smartphone-supported vestibular rehabilitation in individuals with vestibular dysfunction: pilot randomized crossover trial assessing functional clinical outcomes and anxiety</article-title><source>JMIR Rehabil Assist Technol</source><year>2026</year><month>03</month><day>24</day><volume>13</volume><fpage>e84207</fpage><pub-id pub-id-type="doi">10.2196/84207</pub-id><pub-id pub-id-type="medline">41889357</pub-id></nlm-citation></ref></ref-list></back></article>