In the present study, the Feeding/Swallowing Impact Survey (FS-IS) was translated into Italian and cross-adapted according to the guidelines proposed by Beaton et al. [28]. All members of the expert commission involved in the process actively discussed possible solutions to produce a translated instrument that maintained a reading and comprehension level accessible by most respondents, even those with a low level of education, without altering the meaning and content of the original source. For that reason, minimal grammatical or semantic changes were proposed. It is to be noted that the present expert panel did not include anthropologists or sociologists, despite the fact that such inclusion had been recommended by the relevant guidelines [41]. The deglutologist responsible for evaluating the content validity of the scale concluded that the FS-IS-IT was both suitable and equivalent to the original instrument for measuring the impact of PFD in Italian caregivers of children with heterogeneous conditions. Furthermore, during the caregiver testing phase, no problems with item comprehension were reported.

In contrast to previous studies, we included both mother and father for each child. In fact, in line with many studies focusing mainly on the female figure, some validation studies of the FS-IS in other languages have only included mothers [23–24], or fathers are generally underrepresented [22, 25]. However, recent evidence highlights the importance of involving fathers in the care of children with special needs [15]. Therefore, this study aims to verify the impact of PFD on parental dyads, highlighting the importance of involving fathers in the rehabilitation process.

The final version was deemed appropriate and easy to understand, with evidence of reliability and validity for both subgroups (fathers and mothers). Moreover, the study assessed the diagnostic properties of the instrument for the first time. Specific cut-offs were identified to discriminate between parents of children with PFD and parents of children with disabilities but without these symptoms. The results enabled the development of the first valid instrument capable of measuring the impact of PFD on the quality of life of parents of children with disabilities in Italy.

Regarding reliability analyses, the FS-IS-IT internal consistency met satisfactory parameters, similar to the previous FS-IS validation studies [22–23, 25]. In contrast to previous studies, which utilized Cronbach’s alpha coefficient, the present study opted to employ McDonald’s Omega coefficient (ω). Indeed, recent evidence suggests that Cronbach’s Alpha coefficient (α) is based on assumptions, whereas McDonald’s Omega coefficient (ω) is based on fewer and more realistic assumptions. Additionally, calculating McDonald’s Omega coefficient (ω) alongside a confidence interval considers variability in the estimation process more closely, resulting in a more precise level of confidence in the consistency of the scale adjustment [42]. Differently from alpha, omega is based on a factor analysis result. As for alpha, internal consistency is usually considered acceptable if the estimate is 0.70 or higher [43]. The ω values obtained for both fathers and mothers could be interpreted as indicating satisfactory internal consistency of the FS-IS-IT. Additionally, the test-retest reliability of the FS-IS-IT was found to be high, indicating its stability and reliability over two weeks. This period reduced recall bias and ensured the stability of patients’ health status between the two assessment sessions.

The validity of the FS-IS-IT was established in the present study through the analyses of criterion and convergent validity. Criterion validity was previously evaluated using the PedsQL™ FIM [36], a multidimensional tool for assessing family quality of life. However, this tool has not yet been validated in Italian. Therefore, the Italian version of the ZBI was chosen as the gold standard. This tool was developed based on Zarit’s definition of caregiver burden, which encompasses the extent to which caregivers perceive financial, physical, and spiritual strain. The ZBI is a widely used tool for evaluating caregiver burden and has demonstrated adequate psychometric properties [35]. It has also been utilized in the pediatric field [44,45,46]. It is important to note that burden should not be equated with quality of life. The latter encompasses positive and negative effects that may coexist for caregivers [47]. However, since the FS-IS-IT questionnaire assesses the impact of a PFD on the caregiver, the ZBI could be considered an appropriate measure.

As expected, moderate to strong statistically significant inverse correlations were observed between the FS-IS-IT and its subscales and the ZBI score in both groups of fathers and mothers. To date, most literature has used the ZBI to assess the burden of dysphagia on caregivers in adulthood and old age, particularly in the context of dementia [48]. In the pediatric setting, it has primarily been used to assess the burden related to enteral nutrition [49]. However, this finding is consistent with previous studies that the presence of PFD is strongly associated with higher levels of burden on caregivers [50–51]. In line with previous studies, caregivers of children with PFD (both fathers and mothers) reported significantly higher levels of burden than caregivers of children without feeding difficulties [52].

Based on the previous hypothesis, the FS-IS-IT total score and subscales have a low-to-mild correlation with the IDDSI Functional Diet Scale. The present analyses showed that only the third subscale in the mothers’ subgroup had a statistically significant correlation with the IDDSI Functional Diet Scale based on Bonferroni correction. This result could be attributed to the lack of sufficient power to find a significant correlation in the present study. Therefore, future studies with larger samples are necessary. Moreover, our sample included children with feeding difficulties who consumed multiple consistencies but had food phobias or very rigid food choices. It is assumed that the parents of these children experience a high level of stress and that the impact of the disorder is significant [53], similar to the parents of children with dysphagia. In accordance with the hypothesis, a recent study by Silverman et al. [54] observed that parents of children who exclusively exhibit problematic mealtime behaviors (e.g., verbal refusal, food avoidance, food selectivity, etc.) despite their children consuming a variety of consistencies reported feelings of parental ineptitude and experienced high levels of stress. However, as the child consumes a variety of consistencies, the IDDSI Functional Diet score is high, thereby limiting the strength of the correlation. Consequently, the present findings suggest that the analysis of the child’s diet alone may not suffice to explain the parental burden experienced. To date, no studies have mapped factors associated with parental burden in case of PFD; however, future studies with a large sample could investigate which factors have the greatest impact. The significant correlation between the IDDSI Functional Diet Scale and the ‘Feeding Difficulties’ subscale in the mothers’ group supports the hypothesis that mothers of children with greater food restrictions experience more practical difficulties in preparing and serving food and drinks. Literature demonstrates that caregivers face challenges during mealtimes, including preparing and offering adequate food and liquids, increased time spent eating, and pressure to provide sufficient food. This evidence corroborates these findings [55, 56]. Furthermore, this result confirms those of previous studies that translated the FS-IS into Brazilian Portuguese [25] and Turkish [23]. These studies demonstrated that the Feeding Difficulties subscale effectively differentiated caregivers of children with and without oral feeding, respectively, or between caregivers of children who aspirated and those who did not. Caregivers face challenges during mealtimes, including preparing and offering adequate food and liquids, increased time spent eating, and pressure to provide sufficient food.

The diagnostic properties of the FS-IS-IT has not been previously assessed in validation studies, and no cut-off has yet been investigated. Previous studies have only assessed the discriminant validity between subjects with milder forms of dysphagia and more severe forms, based on instrumental assessments [23] or clinical assessments, such as the presence of parenteral nutrition [22, 25]. Conversely, the present study has showed that the scale can effectively differentiate between parents of children with PFD and parents of children with disabilities but without these difficulties, with high sensitivity and specificity. Additionally, specific cut-off scores for fathers and mothers have been derived for FS-IS-IT. The study found that the FS-IS-IT is a suitable screening tool for identifying PFD in parents of children with disabilities compared to parents of children with disabilities but without PFD. The sensitivity at this point was 94% and 81%, while the specificity was 87% and 93% for the mother and father, respectively. This set of data will prove to be of significant value in clinical practice, and that it constitutes part of the evidence supporting the construct validity of the FS-IS-IT, particularly the known group validity. The study also provides empirical data showing that the quality of life of the caregiver of a child with PFD is impaired. However, it should be noted that the distribution of medical diagnoses and impairments in the study population is reflective of the population of the Centre where the study was conducted. Consequently, these distributions cannot be extrapolated to the PFD population. Therefore, a larger study with different populations and ages should be conducted to confirm our results. Furthermore, the burden should be influenced by culture, especially for topics related to eating and meals. Therefore, studies conducted in different countries should be useful in investigating the different impact of culture.

As hypothesized, fathers were found to be less involved in their children’s feeding than mothers in both groups of parents of children with disabilities, with or without PFD, although no statistical difference was observed between dyads in the same groups at FS-IS-IT scores. Surprisingly, the percentage of fathers involved in feeding management is statistically significantly greater in the non-PFD group than in the other group (X-squared = 4.8763, df = 1, p-value = 0.02723). It is noteworthy that fathers of children with disabilities but without PFD were involved in their children’s feeding in about 80% of cases. This finding is consistent with recent research showing that fathers are increasingly involved in their children’s care [57]. Additionally, the definition of fatherhood has expanded to encompass traditionally considered feminine activities [58].

In contrast, when it comes to the group of children with PFD, only about 40% of fathers report taking care of their children’s feeding, leaving the mother as the primary caregiver. To understand the reasons for this disparity, it would be appropriate to conduct studies with larger samples using qualitative methods such as interviews and focus groups to explore the underlying motivations in depth. Mothers may be more involved in the care of their children with PFD due to their greater knowledge of feeding procedures. Although fathers are increasingly involved in housework and childcare, they are still not significantly involved in their children’s rehabilitation. Therefore, fathers may have less information and strategies to deal with feeding difficulties, leaving the task to the mother figure.

However, contrary to the initial hypothesis, the study found no statistically significant difference between the total score of the FS-IS-IT and its subscales obtained from fathers and mothers of children with PFD. This suggests that PFD have a comparable impact on both members of the dyad. Parents face similar challenges in their daily lives and share concerns about their children’s health. They also experience comparable difficulties in managing mealtimes and feeding. Child health professionals and services should sensitize and prepare health teams, including all stakeholders, to welcome and value male participation. This includes involving fathers in circles of discussion, reflection, and sharing of experiences and concerns. This could lead to a more equitable sharing of childcare responsibilities, with fathers feeling more engaged and willing, and could reduce the burden on both parents. Indeed, a growing body of literature has demonstrated the need for holistic family-centered approaches that ensure the care of the whole family in order to reduce the burden of care. Parents with adequate resources and support, as well as physical and psychological health, are able to provide a positive caregiving environment, which is therefore fundamental to the success of habilitative interventions for the child. Involving both fathers and mothers may also facilitate the generalization of skills learned in the therapeutic setting to other life contexts [59].

Finally, the present study found that the impact of a child’s PFD on the caregiver was greater than that reported in the original article [22], but as observed by Simione et al. [60], total scores ranged from 1.9 to 3.3, which is similar to other FS-IS validation studies [25]. As suggested by Rama et al. [25] and Simione and colleagues [60], these discrepancies may be due to differences in the children’s age, varying study populations, and the survey’s timing. In contrast to the original study, we enrolled older children with different aetiologies, including autism. The median age of the children in our study was 52 months, compared to 14 months in the original study. We also included patients at the time of their initial assessment and during follow-up. Moreover, contrary to our expectations and a previous study [25], we did not find any significant relationship between FS-IS-IT scores and education levels. Therefore, it can be hypothesized that the observed variability in total scores on the FS-IS may be ascribed to a number of factors, including the etiology of the feeding impairment, the age group, and the demographic characteristics of the caregivers, amongst others. Regrettably, we were also unable to undertake comparative analyses of differences between the groups with different medical diagnoses, age ranges, or impairments due to insufficient statistical power. Consequently, the implementation of a future study involving a large sample of caregivers of children with PFD who exhibit diverse characteristics (e.g., age, diagnosis, diet, etc.) may contribute to the enhancement of the tool’s construct validity.

The present study is not without limitations. The relatively small sample size calls for caution when interpreting the results, especially since it is the first study to analyze the psychometric properties of the FS-IS for both mothers and fathers. Additionally, the lack of instrumental assessment of swallowing as a construct validity is a limitation of this study. Regrettably, numerous patients lack access to these assessment methods and must rely on clinical diagnosis. Furthermore, only a small proportion of children experienced significant limitations in their diet consistency or alternative feeding channels. In addition, children with congenital craniofacial malformations, which can be associated with feeding and swallowing difficulties, are under-represented in our sample.

Finally, the lack of factor and response analyses should be acknowledged as a limitation of the present study, as no claims can be made about the construct(s) underlying FS-IS-IT and its ability to reflect clinically significant changes over time on the basis of the present results. It is important to note that a sample size of at least 100 participants with 4–10 participants per item is required to conduct factor analyses [61]. Although our study included over 90 carers, as with other validation studies [23, 25], the presence of clusters (dyads) requires a large number of subjects. Future research studies with larger samples of carers of children with mild to relevant feeding and swallowing problems from different aetiologies are needed to confirm the results of the present study and enhance new results on the psychometric properties of the FS-IS-IT scale.