{"id":515,"date":"2025-04-20T13:52:04","date_gmt":"2025-04-20T12:52:04","guid":{"rendered":"https:\/\/bhowmicksays.in\/?p=515"},"modified":"2025-04-20T13:52:04","modified_gmt":"2025-04-20T12:52:04","slug":"clinical-masking-in-audiology-cross-hearing-interaural-attenuation-the-plateau-method","status":"publish","type":"post","link":"https:\/\/bhowmicksays.in\/?p=515","title":{"rendered":"Clinical Masking in Audiology: Cross Hearing, Interaural Attenuation &amp; the Plateau Method"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Why Do Audiologists Use Masking During Hearing Tests?<\/h2>\n\n\n\n<p>If you\u2019ve ever had a hearing test, you might\u2019ve noticed the audiologist playing sounds in one ear while adding noise to the other. Strange, right? But there\u2019s a smart reason for it! This technique is called <strong>clinical masking<\/strong> \u2014 and it helps make sure each ear is tested correctly, one at a time.<\/p>\n\n\n\n<!--more-->\n\n\n\n<p>In this blog, you\u2019ll learn:<\/p>\n\n\n\n<ul>\n<li>What cross hearing is (and why it happens)<\/li>\n\n\n\n<li>How interaural attenuation (IA) affects sound<\/li>\n\n\n\n<li>Why the plateau method is the gold standard for accurate results<\/li>\n<\/ul>\n\n\n\n<p>Let\u2019s break it all down!<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">What Is Cross Hearing?<\/h2>\n\n\n\n<p>During a hearing test, sounds are sent to one ear at a time. But if the sound is loud enough, it can &#8220;leak&#8221; through your skull and reach the other ear. This is called <strong>cross hearing<\/strong>.<\/p>\n\n\n\n<p><strong>Why is this a problem?<\/strong><br>Because if the non-test ear hears the sound and responds, your results won\u2019t be accurate.<\/p>\n\n\n\n<p>That\u2019s where <strong>masking noise<\/strong> comes in. It blocks the non-test ear so the audiologist can be sure they\u2019re testing the correct one.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Interaural Attenuation (IA): How Sound Travels Between Ears<\/h2>\n\n\n\n<p>When sound travels from one ear to the other, it loses some strength. This loss is called <strong>interaural attenuation (IA)<\/strong>.<\/p>\n\n\n\n<p><strong>What affects IA?<\/strong><\/p>\n\n\n\n<ol>\n<li><strong>The type of transducer (testing device)<\/strong>\n<ul>\n<li><strong>Bone vibrator:<\/strong> No sound loss (IA = 0 dB) \u2192 High chance of cross hearing.<\/li>\n\n\n\n<li><strong>Supra-aural headphones:<\/strong> Moderate sound loss (~40 dB IA).<\/li>\n\n\n\n<li><strong>Insert earphones:<\/strong> Highest sound loss (~70 dB IA) \u2192 Least likely to cross over.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>The sound\u2019s frequency.<\/strong><br>Higher or lower frequencies behave differently, but the device used has the biggest impact.<\/li>\n<\/ol>\n\n\n\n<p><strong>Key point:<\/strong><br>Lower IA means sound can easily reach the wrong ear. When this happens, masking becomes necessary!<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">When Is Masking Needed in Hearing Tests?<\/h2>\n\n\n\n<p>Audiologists use masking when they suspect cross hearing might affect your results.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img fetchpriority=\"high\" decoding=\"async\" width=\"683\" height=\"1024\" src=\"https:\/\/bhowmicksays.in\/wp-content\/uploads\/2025\/04\/Why-is-masking-necessary-683x1024.jpg\" alt=\"\" class=\"wp-image-517\" style=\"width:556px;height:auto\" srcset=\"https:\/\/bhowmicksays.in\/wp-content\/uploads\/2025\/04\/Why-is-masking-necessary-683x1024.jpg 683w, https:\/\/bhowmicksays.in\/wp-content\/uploads\/2025\/04\/Why-is-masking-necessary-200x300.jpg 200w, https:\/\/bhowmicksays.in\/wp-content\/uploads\/2025\/04\/Why-is-masking-necessary-768x1152.jpg 768w, https:\/\/bhowmicksays.in\/wp-content\/uploads\/2025\/04\/Why-is-masking-necessary.jpg 1024w\" sizes=\"(max-width: 683px) 100vw, 683px\" \/><\/figure>\n\n\n\n<p>Common signs:<\/p>\n\n\n\n<ul>\n<li>The <strong>air-bone gap<\/strong> between the test ear AC and the better BC (<strong>Air opposite bone gap)<\/strong>  is: \n<ul>\n<li>more than <strong>10 dB<\/strong>. (BC masking)<\/li>\n\n\n\n<li>more than <strong>40 dB <\/strong>(AC masking)<\/li>\n\n\n\n<li>more than <strong>70 dB <\/strong>(AC masking insert earphones)<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>The sound is strong enough to reach the <strong>non-test ear\u2019s hearing threshold<\/strong>.<\/li>\n\n\n\n<li>Presence of a shadow curve.<\/li>\n<\/ul>\n\n\n\n<p>Without masking, the test might pick up the wrong ear\u2019s response \u2014 leading to an inaccurate result.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">The Plateau Method: Finding the True Hearing Threshold<\/h2>\n\n\n\n<p>Introduced by Hood in 1960, the <strong>plateau method<\/strong> is the most trusted way to confirm hearing test results.<\/p>\n\n\n\n<p><strong>Here\u2019s how it works:<\/strong><\/p>\n\n\n\n<ol>\n<li>The audiologist increases the masking noise in the non-test ear step by step.<\/li>\n\n\n\n<li>If the test ear\u2019s response stays the same for a few steps, this steady range is called the <strong>plateau<\/strong>.<\/li>\n\n\n\n<li>The hearing level recorded in the plateau is your <strong>true threshold<\/strong>.<\/li>\n<\/ol>\n\n\n\n<p><strong>How the Plateau Method Works (Step-by-Step)<\/strong><\/p>\n\n\n\n<p>\ud83d\udc49 Start with a <strong>5 dB step size<\/strong> for both the tone and the masking noise.<\/p>\n\n\n\n<ul>\n<li>If the person <strong>hears the tone<\/strong>:<br>\ud83c\udfa7 <strong>Keep the tone level the same<\/strong> and <strong>increase the noise<\/strong> by 5 dB.<\/li>\n\n\n\n<li>If the person <strong>doesn\u2019t hear the tone<\/strong>:<br>\ud83d\udd0a <strong>Keep the noise level the same<\/strong> and <strong>increase the tone<\/strong> by 5 dB.<\/li>\n<\/ul>\n\n\n\n<p>\ud83d\udca1 <strong>Once you get three consecutive \u201cyes\u201d responses<\/strong> \u2014 where the tone stays the same but the masking noise is still going up \u2014 that spot is the <strong>true threshold<\/strong> of the test ear!<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">3 Masking Zones to Know:<\/h3>\n\n\n\n<ul>\n<li><strong>Under-masking:<\/strong> The noise is too soft. The non-test ear still helps out.<\/li>\n\n\n\n<li><strong>Plateau:<\/strong> The perfect range \u2014 only the test ear is responding.<\/li>\n\n\n\n<li><strong>Over-masking:<\/strong> The noise is too loud and starts affecting the test ear, making results unreliable.<\/li>\n<\/ul>\n\n\n\n<p>The audiologist\u2019s goal is always to reach the plateau for clear, accurate hearing test results.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83c\udfaf <strong>Handy Masking Formulas for Audiology<\/strong><\/h3>\n\n\n\n<p>When it comes to clinical masking, there are key formulas you should know. These help audiologists set the right noise levels in the non-test ear during a hearing test!<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h4 class=\"wp-block-heading\">\ud83d\udca1 <strong>Minimum Masking Level<\/strong><\/h4>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<p>MML = Air Conduction Threshold of Non-Test Ear (NTE) + 10 dB + Occlusion Effect (if applicable)<\/p>\n<\/blockquote>\n\n\n\n<p>\ud83d\udc49 <em>This is the starting point for masking. The extra 10 dB ensures the noise is loud enough to block out the non-test ear&#8217;s response. If you&#8217;re testing bone conduction, don\u2019t forget to add the occlusion effect based on the frequency!<\/em><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h4 class=\"wp-block-heading\">\ud83d\udca1 <strong>Maximum Masking Level (MML)<\/strong><\/h4>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<p>MML BC = Bone Conduction Threshold of the Non Test Ear (NTE) + Interaural Attenuation (IA)<\/p>\n\n\n\n<p>MML AC = Bone Conduction Threshold of the Test Ear (TE) + Interaural Attenuation (IA)<\/p>\n<\/blockquote>\n\n\n\n<p>\ud83d\udc49 <em>This is the upper limit for masking. If you go beyond this, the noise might actually cross back over and affect the test ear \u2014 which we call over-masking.<\/em><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Why Masking Matters<\/h2>\n\n\n\n<p><strong>Clinical masking<\/strong> may sound technical, but it\u2019s key to getting reliable hearing test results. It stops one ear from \u201ccheating\u201d for the other!<\/p>\n\n\n\n<p>By using masking and the plateau method, audiologists make sure your hearing levels are measured correctly \u2014 ear by ear.<\/p>\n\n\n\n<p>So, next time you hear that masking noise during your test, don\u2019t worry. It\u2019s not there to confuse you \u2014 it\u2019s there to help you!<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>Got questions about hearing tests or masking?<\/strong><br>Ask your audiologist, or me if you want to \u2014 we\u2019ll be happy to help!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Why Do Audiologists Use Masking During Hearing Tests? If you\u2019ve ever had a hearing test,&#8230;<\/p>\n","protected":false},"author":1,"featured_media":518,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_eb_attr":"","om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[5],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=\/wp\/v2\/posts\/515"}],"collection":[{"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=515"}],"version-history":[{"count":4,"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=\/wp\/v2\/posts\/515\/revisions"}],"predecessor-version":[{"id":523,"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=\/wp\/v2\/posts\/515\/revisions\/523"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=\/wp\/v2\/media\/518"}],"wp:attachment":[{"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=515"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=515"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bhowmicksays.in\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=515"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}