本研究者嘗試以前兆行為（precursor behavior）之行為功能分析（functional analysis）與介入的方式，改善一位極重度自閉症高職學生之一連串自動增強的行為問題，例如：連續敲擊物品、咬人與頭撞人或地板，或是在椅子上大力跳動等。當特教生行為問題本身的嚴重程度，在倫理上不允許我們使用行為功能分析去誘發行為問題的時候，近代學界有一些建議的作法。其中一個作法，是以和嚴重行為問題相同反應群的前兆行為，取代個案嚴重行為問題本身的評量與介入。本研究以較為緩和的連續敲擊物品作為前兆行為，研究目的如下：1、執行行為功能評量找出前兆行為之功能，2、在得出前兆行為功能為自動增強後，運用訪談與觀察刪去不適配之感覺輸入形式，最後以海綿及耳塞之觸覺替代策略，以期改善研究對象前兆行為的發生次數。本研究採用單一受試研究法之多元素設計（multi-element design）進行前兆行為功能分析，並採用快速重複不斷基線—介入倒返設計（constant reversal design），評估執行海綿與耳塞兩種觸覺輸入替代策略之成效。本研究結果顯示，使用耳塞的感覺輸入替代之介入策略能顯著降低研究對象連續敲擊物品之前兆行為，兩者間具有功能關係（functional relationship）。本研究開啟了臺灣在處理嚴重行為問題時採用前兆行為評量與介入的實證序端，然而，本團隊並非教育現場工作者為其限制之一，建議未來能由教育現場工作者擔任研究者，更進一步將實證性、更積極的教育介入策略應用於教育現場，以落實行為功能評量與介入的重要意涵。

Severe challenging behavior is an unexplored research topic in Taiwan. A recent recommended practice is to indirectly address challenging behavior by assessing and manipulating its less severe and relatively moderate precursor behavior. This practice has the potential to mitigate the necessity of evoking severe challenging behavior and to address ethical concerns when conducting functional analysis. The research team implemented functional analysis and intervention on precursor behavior in order to improve a series of challenging behaviors (i.e., constant tapping objects, biting or hitting a person, hitting floor with head, and vigorously hopping on chair) of a vocational high school student with profound autism. In this case, we selected the tapping objects as the precursor behavior. Purpose: This study examined the results of a functional analysis on the precursor behavior and explored the role automatic reinforcement alternative tactile intervention plays in eliminating this behavior in a student with profound autism. Methods: We used a single-subject multi-element research design with functional analysis and constant reversal design to establish internal validity of the effectiveness of the intervention. The research team conducted a two-phase study: In the first phase, we conducted a functional behavior assessment, comprising functional analysis and masking assessment to validate the hypotheses of automatic reinforcement function of precursor behavior and then the sensory input of automatic reinforcement. In the second phase, after confirming the tactile sensory input which was reinforcing the precursor behavior, we selected sponge and ear plug to investigate the effects. Results/Findings: Results from this study confirmed a functional relationship between using ear plugs as an alternative sensory input and decreasing precursor behavior (i.e., tapping objects). Furthermore, based on anecdotal observation, all other severe challenging behaviors were then eliminated. Conclusions/Implications: This study established initial evidence of effectiveness in precursor behavior assessment in Taiwan. Although the literature indicated precursor assessment may not be applicable for the function of automatic reinforcement as we are not able to control its consequence, this study, however, showed direct intervention with different sensory inputs may be a rational choice for eliminating automatic reinforcement precursor behavior. Finally, the limitation of an external research team led us to suggest encouraging practitioners to be more involved in research to address social validity in response to the literature gap of functional behavior assessment and intervention. Practitioners as researchers also can ensure implementation of more proactive education strategies, such as expanding students' interest and teaching social-communication skills.