the ipca questionnaire ( see below ) was sent to 190 parents who were members of the dutch rett syndrome parent association and who had a child with rett syndrome . in an accompanying letter , parents were asked to complete the ipca jointly . if their child lived in a residential facility , they were asked to complete the ipca together with a staff member who knew the child well . participants were 120 females , and their mean age in years was 21.1 ( sd  =  11.97 ; range : 555 ) . rett syndrome was confirmed ( mecp2 mutation ) in 89 ( 74% ) of the cases . of the participants , 50% had classic or typical rett syndrome , 24% had atypical rett syndrome while syndrome type was unknown in 26% of the participants . most participants ( 65% ) lived at home with his or her parents , 35% lived in a residential facility , and/or 8% lived in a community based group home . of the sample , 72 females ( 60% ) had epilepsy , of which 29 ( 40% ) were seizure - free as a result of anticonvulsive medication . most participants ( 76% ) had breathing difficulties / disturbances of whom 35 ( 38% ) showed shallow breathing , 29 ( 32% ) had hyperventilation , 70 ( 76% ) had breath holding spells , 30 ( 33% ) showed forced expulsion of air . most participants ( i.e. , n  =  90 ; 75% ) were wheelchair bound and scoliosis was present in 73 females ( 61% ) . the ipca is a tool for the assessment of form and function of communicative behavior in people with severe communication impairments . it seeks to identify potential communicative acts or communicative forms that may be used by an individual for any of 10 communicative functions . a potential communicative act is defined as any behavior that the informant has identified as being used by the participant for communicative purposes the ipca is based on an extensive review of the literature and analyses of communicative forms and functions expressed by individuals with developmental disabilities and communication impairment ( see e.g. sigafoos et al . ten categories of communicative function are delineated and accompanying questions are used to identify the forms of behavior that the child uses to accomplish each of these ten communication function . these categories ( and example questions ) are ( a ) social convention ( e.g.  how does your child greet you? ) , ( b ) attention to self ( e.g.  how does your child request your attention? ) , ( c ) reject / protest ( e.g.  what does your child do if a routine is disrupted? ) , ( d ) request an object ( e.g.  how does your child let you know that s / he wants something? ) , ( e ) request an action ( e.g.  how does your child let you know that s / he wants help with dressing? ) , ( f ) request information ( e.g.  how does your child let you know that s / he needs clarification if s / he does not understand? ) , ( g ) comment ( e.g.  how does your child let you know that s / he is happy? ) , ( h ) choice making ( e.g.  how does your child choose between two objects? ) , ( i ) answer ( e.g. ,  how does your child react when someone talks to him / her? ) , and ( j ) imitation ( e.g.  how does your child imitate something that you say or do? ) . the ipca was developed through initial field testing with 30 children with developmental disabilities and severe communication impairments ( sigafoos et al . the results of that field testing indicated that the ipca was appropriate for gathering descriptive information on the existing pre - linguistic communicative behaviors of children with developmental disabilities and severe communication impairments ( sigafoos et al . field testing also indicated good agreement between parents and teacher informants , suggesting the ipca has adequate inter - informant agreement for the purpose of identifying the existing pre - linguistic communicative behaviors of children with developmental disabilities and severe communication impairments ( sigafoos et al . the ipca has also been shown to have adequate predictive validity for identifying intervention targets in programs aimed at replacing pre - linguistic communication acts with more formal communication skills ( keen et al . the ipca was translated into dutch and completed by parents and caretakers who knew the participant for at least 6  months . for the purpose of this study , several additional questions were added ( e.g. , type and stage of rett syndrome , age , epilepsy , breathing difficulties , scoliosis , and living setting ) . parent and caregiver informants were asked to describe the communicative behaviors ( i.e. forms ) that s / he had observed in the individual with rett syndrome for each of the above ten categories . in the ipca , a wide variety of examples of communicative behaviors or forms are given as examples from which the informant may choose . these are nonsymbolic ( e.g. , eye gazing , pointing , facial expressions , bodily movements , vocalizations , challenging behavior ) and symbolic communicative behaviors ( e.g. , use of pictures , and pointing to a picture on a communication board ) . informants were encouraged to mention other communicative behaviors that were not included in the list of examples of communicative acts . the first analysis was percentage of individuals with rett syndrome who showed each communicative form for each of the ten communicative functions . this was calculated for the overall sample based on the communicative behaviors that were mentioned by respondents . following this , comparisons were made of the percentage of individuals that showed each communicative form and function by syndrome stage , presence of epilepsy / breathing difficulties , age , and living environment . the ipca questionnaire ( see below ) was sent to 190 parents who were members of the dutch rett syndrome parent association and who had a child with rett syndrome . in an accompanying letter , parents were asked to complete the ipca jointly . if their child lived in a residential facility , they were asked to complete the ipca together with a staff member who knew the child well . participants were 120 females , and their mean age in years was 21.1 ( sd  =  11.97 ; range : 555 ) . rett syndrome was confirmed ( mecp2 mutation ) in 89 ( 74% ) of the cases . of the participants , 50% had classic or typical rett syndrome , 24% had atypical rett syndrome while syndrome type was unknown in 26% of the participants . most participants ( 65% ) lived at home with his or her parents , 35% lived in a residential facility , and/or 8% lived in a community based group home . of the sample , 72 females ( 60% ) had epilepsy , of which 29 ( 40% ) were seizure - free as a result of anticonvulsive medication . most participants ( 76% ) had breathing difficulties / disturbances of whom 35 ( 38% ) showed shallow breathing , 29 ( 32% ) had hyperventilation , 70 ( 76% ) had breath holding spells , 30 ( 33% ) showed forced expulsion of air . most participants ( i.e. , n  =  90 ; 75% ) were wheelchair bound and scoliosis was present in 73 females ( 61% ) . the ipca is a tool for the assessment of form and function of communicative behavior in people with severe communication impairments . it seeks to identify potential communicative acts or communicative forms that may be used by an individual for any of 10 communicative functions . a potential communicative act is defined as any behavior that the informant has identified as being used by the participant for communicative purposes ( sigafoos et al . the ipca is based on an extensive review of the literature and analyses of communicative forms and functions expressed by individuals with developmental disabilities and communication impairment ( see e.g. sigafoos et al . ten categories of communicative function are delineated and accompanying questions are used to identify the forms of behavior that the child uses to accomplish each of these ten communication function . these categories ( and example questions ) are ( a ) social convention ( e.g.  how does your child greet you? ) , ( b ) attention to self ( e.g.  how does your child request your attention? ) , ( c ) reject / protest ( e.g.  what does your child do if a routine is disrupted? ) , ( d ) request an object ( e.g.  how does your child let you know that s / he wants something? ) , ( e ) request an action ( e.g.  how does your child let you know that s / he wants help with dressing? ) , ( f ) request information ( e.g.  how does your child let you know that s / he needs clarification if s / he does not understand? ) , ( g ) comment ( e.g.  how does your child let you know that s / he is happy? ) , ( h ) choice making ( e.g.  how does your child choose between two objects? ) , ( i ) answer ( e.g. ,  how does your child react when someone talks to him / her? ) , and ( j ) imitation ( e.g.  how does your child imitate something that you say or do? ) . the ipca was developed through initial field testing with 30 children with developmental disabilities and severe communication impairments ( sigafoos et al . the results of that field testing indicated that the ipca was appropriate for gathering descriptive information on the existing pre - linguistic communicative behaviors of children with developmental disabilities and severe communication impairments ( sigafoos et al . field testing also indicated good agreement between parents and teacher informants , suggesting the ipca has adequate inter - informant agreement for the purpose of identifying the existing pre - linguistic communicative behaviors of children with developmental disabilities and severe communication impairments ( sigafoos et al . the ipca has also been shown to have adequate predictive validity for identifying intervention targets in programs aimed at replacing pre - linguistic communication acts with more formal communication skills ( keen et al . the ipca was translated into dutch and completed by parents and caretakers who knew the participant for at least 6  months . for the purpose of this study , several additional questions were added ( e.g. , type and stage of rett syndrome , age , epilepsy , breathing difficulties , scoliosis , and living setting ) . parent and caregiver informants were asked to describe the communicative behaviors ( i.e. forms ) that s / he had observed in the individual with rett syndrome for each of the above ten categories . in the ipca , a wide variety of examples of communicative behaviors or forms are given as examples from which the informant may choose . these are nonsymbolic ( e.g. , eye gazing , pointing , facial expressions , bodily movements , vocalizations , challenging behavior ) and symbolic communicative behaviors ( e.g. , use of pictures , and pointing to a picture on a communication board ) . informants were encouraged to mention other communicative behaviors that were not included in the list of examples of communicative acts . the first analysis was percentage of individuals with rett syndrome who showed each communicative form for each of the ten communicative functions . this was calculated for the overall sample based on the communicative behaviors that were mentioned by respondents . following this , comparisons were made of the percentage of individuals that showed each communicative form and function by syndrome stage , presence of epilepsy / breathing difficulties , age , and living environment . percentages of females with rett syndrome who showed communicative forms for each of the ten communicative functions are shown in table  1 . a variety of communicative forms were used of which the most common types were eye contact / gazing and laughing / smiling . only 15 to 16% of the females used some type of symbolic communication ( i.e. speech / words ) for the purpose of requesting . in our sample , other symbolic communication forms , such as manual signs or voice output devices , were not mentioned by respondents . the most often endorsed communicative functions were social convention , commenting , answering , requesting and choice - making . problematic topographies ( e.g. , self - injury , screaming , non - compliance ) were being used for communicative purposes in 10 to 41% of the sample . such topographies were mainly used for the purpose of commenting , and requesting an object , attention and/or action . finally , only a small number of females ( 13% ) showed stereotyped hand movements and this behavior was shown for the purpose of commenting . table  1percentages of females with rett syndrome showing communicative forms for each of the ten communicative functionssocial convention%attention to self%reject / protest%request an object%request an action%request information%comment%choice making%answer%imitation%eye contact / gaze95touch person50looking away32eye contact / gaze67vocalization39eye contact / gaze48laughing / smiling93eye contact / gaze59eye contact / gaze76eye contact / gaze47laughing / smiling83eye contact / gaze46screaming31vocalization25eye contact / gaze30words / speech16crying68touch21laughing / smiling25vocalization40vocalization13vocalization38crying29reaching20screaming18touch person12screaming41looking away20looking away25approaching person12screaming24being tense27taking object17words / speech15facial expression40approaching16mouth closure17words / speech21distancing from person11crying21eye contact / gaze26approaching16crying10looking afraid31taking object14looking happy12laughing / smiling19approaching person19resisting25grumbling14whining10vocalization30reaching13head nodding11laughing / smiling14grumbling18mouth open13being tense30distancing12whining13whining15screaming12distancing from person28laughing / smiling10distancing from person15laughing10looking away23laughing / smiling13whining22mouth closure13eye contact / gaze22temper tantrum11looking sad21scowling10grumbling18self - injury10body language17self - injury17body rocking16closing eyes14hand movements13hitting10hand clapping10 percentages of females with rett syndrome showing communicative forms for each of the ten communicative functions tables  2 , 3 and 4 show percentages of females with rett syndrome that showed communicative forms and functions as related to other variables . outcomes were compared for females living at home and those living in a residential facility ( table  2 ) , females with and without epilepsy ( table  3 ) , and females in different age groups ( table  4 ) . table  2percentage of females with rett syndrome who are living at home and in a residential facility and who show functions and forms of communicative behaviors , chi - square and p - valuesfunction / formhome ( n  =  68 ) % residential ( n  =  53 ) %  ( df  =  1)psocial conventioneye contact / gaze9791.24laughing / smiling82830.01.92approaching person12110.01.94distancing from person10110.03.86attention to selftouch person54383.32.07approaching person24112.98.08reject / protesteye contact / gaze35910.93.00**resisting21260.57.45grumbling19130.75.39temper tantrum1090.03.88request an objecteye contact / gaze65454.57.03*reaching2293.44.06taking object1891.66.20approaching person2147.34.01*request an actionvocalizing32135.99.01*words / speech1343.23.07request informationeye contact / gaze1280.59.44touch person321.00commentlooking away21384.34.04*whining30134.51.03*closing eyes7235.77.02*hitting1280.59.44choice makingeye contact / gaze52362.94.09approaching person1863.94.05*reaching1543.99.05*distancing from person1343.23.07answerlaughing / smiling60405.10.02*mouth closure18150.14.71looking happy12110.01.94imitationeye contact / gaze22230.01.94words / speech1280.59.44as a result of low cell frequencies no chi - square value can be calculated . fisher s exact test p - value is given*p  <  .05 ; * * p  <  .01table  3percentage of females with rett syndrome with and without epilepsy who show forms and functions of communicative behavior , chi - square and p - valuesfunction / formno epilepsy ( n  =  41 ) % epilepsy ( n  =  72 ) %  ( df  =  1)psocial conventioneye contact / gaze95961.00laughing / smiling78881.74.19approaching person2065.36.02*distancing from person1280.44.51attention to selftouch person56402.63.11approaching person32108.67.00**reject / protesteye contact / gaze27220.31.58resisting37184.81.03*grumbling27114.61.03*temper tantrum1280.44.51request an objecteye contact / gaze63531.20.27reaching12180.67.41taking object2476.91.01*approaching person1781.96.16request an actionvocalization29191.42.23words / speech1562.67.10request informationeye contact / gaze5111.26.26touch person211.00commentinglooking away24320.72.40whining22220.00.97eyes closing10181.41.24hitting1581.09.30choice makingeye contact / gaze44440.00.96approaching person15100.62.43reaching770.01.94distancing from person1737.28.01*answerlaughing / smiling61462.40.12mouth closure17170.00.96looking happy2468.54.00**imitationeye contact / gaze34174.51.03*words / speech1772.82.09as a result of low cell frequencies no chi - square value can be calculated . fisher s exact test p - value is given*p  <  .05 ; * * p  <  .01table  4percentage of children ( 412  years ) , youth ( 1321  years ) and adults ( 2254  years)with rett syndrome who show functions and forms of communicative behaviors , chi - square and p - valuesfunction / formchildren ( n  =  41 ) % youth ( n  =  30 ) % adults ( n  =  50 ) %  ( df  =  1)psocial conventioneye contact / gaze989392.61laughing / smiling7887841.01.61approaching person17108.39distancing from person15108.57attention to selftouch person6350329.06.01*approaching person321788.57.01*reject / protesteye contact / gaze3243616.38.01*resisting2237164.55.10grumbling2430213.43.01*temper tantrum10712.87request an objecteye contact / gaze76633615.18.00**reaching3701019.44.00**taking object241747.98.02*approaching person297414.03.00**request actionvocalization3737615.10.00*words / speech12134.22request informationeye contact / gaze7272.00**tocuh person270.11commentinglooking away2040283.60.17whining3717147.36.03*eyes closing710224.65.10hitting12136.50choice makingeye contact / gaze63472811.50.00**approaching person241048.84.01*reaching2272.01*distancing from person1774.11answerlaughing / smiling71533412.24.00**mouth closure203068.23.02*looking happy10208.33imitationeye contact / gaze2423200.27.87words / speech12108.93as a result of low cell frequencies no chi - square value can be calculated . fisher s exact test p - value is given*p  <  .05 ; * * p  <  .01 percentage of females with rett syndrome who are living at home and in a residential facility and who show functions and forms of communicative behaviors , chi - square and p - values as a result of low cell frequencies no chi - square value can be calculated . fisher s exact test p - value is given percentage of females with rett syndrome with and without epilepsy who show forms and functions of communicative behavior , chi - square and p - values as a result of low cell frequencies no chi - square value can be calculated . fisher s exact test p - value is given percentage of children ( 412  years ) , youth ( 1321  years ) and adults ( 2254  years)with rett syndrome who show functions and forms of communicative behaviors , chi - square and p - values as a result of low cell frequencies no chi - square value can be calculated . fisher s exact test p - value is given results in table  2 show that there were significant differences between females with rett syndrome who lived at home and those living in a facility in eye contact / gaze for the purpose of rejecting and protesting and requesting an object . other significant differences were for  laughing / smiling ( for choice - making and answering ) , and several communicative forms and functions were most often found in females who lived at home than in those living in a facility except for  closing eyes which was more often found in females living in a facility . the presence or absence of epilepsy was related to communicative forms in that more females without epilepsy used  approaching of another person for the purposes of social convention and drawing attention to oneself than females with epilepsy . females without epilepsy for example were more often  looking happy for the purpose of answering than those with epilepsy . generally , communicative forms and functions were more common in females without epilepsy than in those with epilepsy . there were several significant differences in communicative forms / functions between age groups ( see table  4 ) . for example , results suggest a linear trend across age groups in the percentage of females with rett syndrome in terms of communicative forms for the purpose of attracting attention to self , requesting objects , and choice - making . overall , results of the exploratory comparative analyses revealed that several communicative forms and functions were significantly related to living environment , presence / absence of epilepsy , and age . that is , higher percentages of females who showed some forms / functions were found in those who lived at home , who had no epilepsy and who were relatively young . communicative forms and functions were explored in a large sample of females with rett syndrome . far most females used prelinguistic communicative behaviors of which eye contact / gazing was the most common form . females with rett syndrome only rarely use symbolic forms for communication . these results are largely in agreement with those of other studies in this area ( see e.g. cass et al . comparative analyses revealed that some prelinguistic forms and functions of communicative acts for females with rett syndrome were related to living environment , presence / absence of epilepsy , and age . in general , it may be concluded that communicative forms and functions were more prevalent in females who lived at home , in those without epilepsy and in those that were relatively young . these results should however be viewed with caution as our study was mainly descriptive and there may be interaction effects between these variables that might explain differences between subsamples . our finding that communicative abilities were related to age and epilepsy are not in agreement with results from the study by cass et al . furthermore , our finding that very few females used symbolic communication skills ( e.g. words ) is not in agreement with findings from a study by lavas et al . ( 2006 ) who found that more than one third of their sample used some type of symbolic communication ( e.g. communication aids such as picture boards ) . however , it appeared that in the lavas et al.s study participants did not use these aids for communicative purposes . it appears that communicative forms and functions are more developed in females with rett syndrome who live at home as compared to those who live in a residential facility ( see table  2 ) . ( 2009 ) who investigated communicative forms and functions using the ipca in 79 individuals with angelman syndrome . one reason for this outcome is that in home environments communicative behaviors ( e.g. eye contact / gaze , approaching ) are more often elicited and reinforced than in residential facilities . the level of adult attention is much higher in home settings than in residential facilities . prelinguistic behaviors that are spontaneously used by females with rett syndrome may be extinguished if these behaviors ( forms ) are not elicited and reinforced by caregivers in residential settings . it is suggested that intervention should focus on developing further the joint attention behaviors , intentional communications and communicative functions spontaneously used by individuals with disorders in the rett syndrome complex ( dahlgren - sandberg et al . two intervention studies by sigafoos and his colleagues ( i.e. , sigafoos et al . 1995 , 1996 ) in a case series showed that children with rett syndrome may be taught to express choices via eye gazing and reaching and requesting via a  want  symbol . results of these studies suggest that children with rett syndrome may display intentional alternative communicative behaviors and that such behaviors may be taught using instructional procedures ( see duker et al . 2004 ; sigafoos et al . 2009 ) . several limitation of the study should be mentioned . a limitation of the present study is that we did not compare outcomes to those of one or more control groups thereby limiting the generality of our findings . comparative studies in which a sample of individuals with rett syndrome are included have been rarely conducted . for example , matson et al . ( 2008a ) compared communicative skills of a small group ( n  =  6 ) of adult females with rett syndrome to adults with autism and controls . we do not know if the communicative behaviors are indeed communicative as mentioned by parents / caregivers . especially in individuals with rett syndrome it is difficult to assess communicative forms and functions of ( prelinguistic ) behaviors ( see e.g. , dahlgren - sandberg et al . ( 2000b ) have shown that outcomes of the ipca were in agreement with those of naturalistic observations in a small number of girls with rett syndrome suggesting that communicative forms and functions may be identified in these individuals . finally , due to the relatively small sample size , we were not able to analyse interaction effects . that is , associations between communicative forms / functions and other variables may be influenced by their interactions with
in the present study we assessed the forms and functions of prelinguistic communicative behaviors for 120 children and adults with rett syndrome using the inventory of potential communicative acts ( ipca ) ( sigafoos et al . 
 communication disorders quarterly 21:7786 , 2000a ) . 
 informants completed the ipca and the results were analysed to provide a systematic inventory and objective description of the communicative forms and functions present in each individual s repertoire . 
 results show that respondents reported a wide variety of communicative forms and functions . by 
 far most girls used prelinguistic communicative behaviors of which eye contact / gazing was the most common form . 
 the most often endorsed communicative functions were social convention , commenting , answering , requesting and choice - making . 
 problematic topographies ( e.g. , self - injury , screaming , non - compliance ) were being used for communicative purposes in 10 to 41% of the sample . 
 exploratory analyses revealed that several communicative forms and functions were related to living environment , presence / absence of epilepsy , and age . 
 that is , higher percentages of girls who showed some forms / functions were found in those who lived at home , who had no epilepsy and who were relatively young .