**3. Development of spatial competence in the absence of vision**

While the development of spatial cognition has been extensively studied in sighted individuals [50], less effort has been spent in understanding how the sense of space changes during development in children with visual impairment. Specifically, scientific research on the development of auditory localization skills in visually impaired children has provided contrasting results. For example, it has been shown that children with visual disabilities have an excellent spatial hearing, measured as the ability to discriminate differences in sound localization in the horizontal and vertical plane as well as the ability to reach or walk toward the sound source position [76]. On the contrary, several studies suggested that infants and children with severe congenital blindness have a developmental delay in sound localization abilities [23, 77–79] and motor responses to sound [80, 81]. For example, blind children do not reach for objects that produced sounds until the end of the first year, while sighted children start around 5 months [82]. Similarly, blind children show worse performances than sighted children in auditory bisection, minimum audible angle tasks [23], and audio depth tasks [78]. Other studies show mixed results, indicating that children with congenital visual disabilities show an initial neuromotor developmental delay but compensate for the lack of vision developing good manipulatory and walking skills thanks to the exploration of sounding objects in the environment [83]. Studies of proprioceptive localization of immediate and memorized targets have been used to compare the proprioceptive performance of sighted and blind individuals. For instance, it has been shown that early visual deprivation does not necessarily prevent the development of spatial representations in both early blind children [84] and adults [85]. Considering that spatial competence emerges gradually thanks to the reciprocal influence between visual perception and execution of movements [72], it is evident that visually impaired children not only lack the visual input necessary to establish the sensorimotor feedback that typically promotes spatial development, but also manifests a general delay in the acquisition of important locomotor and proprioceptive skills, which may cause them to accumulate much less spatial experience compared to their sighted peers [79, 86, 87]. It has long been known that the development of blind infants is delayed in self-initiated postures and locomotion [79, 88, 89]. While sighted children typically start to perform first individual actions and navigation from the first year of age, blind children without cognitive and motor impairments start to walk at about 30–32 months of age [90]. Moreover, from the first month of life, blind infants show delays in the vestibular and proprioceptive functions due to the lack of integration with the visual inputs typically provided during the development [91]. Finally, since visual feedback represents the most important incentive for actions and thus for the development of locomotion and mobility skills, the onset of several motor milestones (e.g., rolling, crawling, standing, and balancing) can be delayed in visually impaired infants [92, 93], suggesting that the visual feedback of the body is fundamental for the development of self-concept.

To perceive space, visually impaired children typically use hearing and touch. Despite the haptic sense provides essential information about the spatial layout of peripersonal space, such as the size, shape, position, and orientation of objects within reach, it typically conveys information only within the scope of the body. The case of hearing is particularly interesting because the auditory sense is not only the main channel for providing distal information but also it might be superior to all other sensory alternatives because it provides spatial information in both active and passive conditions and it does not necessarily involve direct contact with objects [94, 95]. At the same time, the use of hearing to perceive distal information might be particularly difficult for visually impaired children because in this case, they do not have any sensory feedback about sonorous objects in the far space. On the contrary, the haptic-proprioceptive system can provide accurate spatial data only within the scope of the body itself [96], and therefore a blind person must actively move in the environment to sequentially touch all the stimuli embedded in space. Several factors may contribute to increasing the difficulty in interpreting such contrasting results. For example, many studies on spatial hearing have been conducted within the framework of broader research on cognitive and motor skills development [87, 97] and reaching mixing the motor and the perceptual component of the observed behavior [83, 98]. In addition, different methodological approaches and stimuli have been used to assess similar aspects of auditory spatial perception: for instance, studies performed on visually impaired children under 3 years of age do not employ psychophysical procedures but they frequently use the sound of familiar voices or toys to gather information about auditory localization abilities in blind children [97]. In addition, in some cases, sighted and blind groups of children are not perfectly matched for age range and sometimes use also adults as comparison [76]. Finally, the difference between early and later loss of vision has not been often considered: many studies mix data from children with no visual experience with those of children with partial visual experience in the first period of life [76]. Instead, it has been demonstrated that the onset of blindness has a strong impact on spatial performance in adulthood: for example, late blind individuals who lost vision later in life after a normal visual experience during the first year of life perform equally or even better than sighted participants in several auditory spatial tasks (1, 50, 83, and 300). To summarize, although compensatory mechanisms for spatial perception have been demonstrated in blind adults, it is not clear whether an early visual impairment might delay the development of special auditory spatial skills. The development of spatial cognition is strictly related to the development of social cognition: the ability to independently navigate and orient ourselves in space facilitates engagement in social interactions. Indeed, a delay in the acquisition of language, motor or cognitive skills can have a direct impact on a child's social competence (106, 109, and 246). More recent works highlighted that preschool-age children with visual impairments often have difficulties engaging in positive social interactions, making their assimilation into preschool programs difficult. In fact, many do not display a full range of play behaviors [99–103] and spend more time engaging in solitary play interacting more with adults than with their sighted peers [81, 87, 89, 102–107]. Considering that the interaction among peers is essential for the development of cognitive, linguistic, social, and playing skills [108], the aforementioned delay in the acquisition of social competence in visually impaired children gives rise to feelings of frustration, rather than self-efficacy and independence which characterize the social experience of typical children. Indeed, the lack of visual information during early infancy often constitutes a risk for the development of the personality and emotional competence [89]. Nonetheless, when assessing social competence in visually impaired people, some other factors resulting from the loss of vision should be taken into account. For example, it has been shown that parenting style influences the socio-emotional development of

**257**

*The Role of Vision on Spatial Competence DOI: http://dx.doi.org/10.5772/intechopen.89273*

sighted children [109–113] because parents represent the first influential setting that can produce appreciable differences in developmental outcomes in terms of psychological functions [114, 115]. Inconsistent, hostile and nonsensitive parenting behaviors have been associated with adjustment problems and social adversity during childhood [116, 117] and also with anxiety, depression, and other stress-related illnesses during adolescence [118, 119] and adulthood [120]. We speculate that a similar influence of parenting style holds also for blind children, especially because families of children with visual disabilities are more prone to experience various stressors such as concerns about the social acceptance of the child [121] and to face difficulties in initiating and sustaining social interactions [122], thus they might easily develop an overprotective behavior that negatively influences the social development of the visually impaired child. The negative effects of blindness on socio-emotional competence can be observed also in adulthood, with the impoverishment of the ability to perform everyday activities both in private settings like home and in public settings like workplace. Importantly, the decrease of functional abilities has been linked to the emergence of serious psychological problems in the blind population [123]. Indeed adults with visual impairments tend to feel more socially isolated and not properly supported compared to sighted individuals [123–126] and are at higher risk of developing depressive symptoms [105, 125, 127–131], principally because social competence depends on the ability to utilize visual cues [132]. Overall, several scientific findings suggest that visual impairments, especially if acquired later in life, can have profound consequences for the physical functioning, psychological wellbeing, and health service needs of older adults [133]. Consequently, early therapeutic interventions specifically focused on activities fostering the development of perceptual and motor abilities would improve the quality of life of children and adults with visual impairments. In the next section, we will present some tools developed to improve perceptual skills of visually impaired individuals and propose a new solution

we recently developed for early intervention in visually impaired children.

The acquisition of spatial competence is typically a good indicator of the future ability to independently navigate in the environment and engage in positive social interaction with peers. While for sighted individuals, the visual feedback represents the most important incentive for actions and thus for the development of mobility and social skills, visually impaired individuals strongly rely on auditory and tactile landmarks to encode spatial and social information. Thus, the creation of technological devices to support visually impaired children in their spatial and social development would be a need. Nonetheless, despite the huge recent advancements in technological industry, most of the devices developed so far to address visually impaired population's needs are not widely accepted by adults and not easily adaptable to children [134]. As reported in the previous sections, visual impairments can determine spatial and social impairments during development. Technological support for the blind should fulfill two different but complementary tasks: the first is to substitute the absent sensory information (vision) with other sensory signals (audition and touch) for daily activities, and the second is to support the rehabilitation of impaired functions following sensory loss. This latter aspect is particularly important when the visual impairment occurs during the first year of life, because technological devices might represent an opportunity for children to develop perceptual and cognitive abilities by compensating for the sensory deprivation. Most of the technological supports developed to date have fulfilled mainly the first task, namely the substitution of vision with other modalities for everyday tasks such as object recognition.

**4. Spatial tools for visually impaired children**

#### *The Role of Vision on Spatial Competence DOI: http://dx.doi.org/10.5772/intechopen.89273*

*Visual Impairment and Blindness - What We Know and What We Have to Know*

To perceive space, visually impaired children typically use hearing and touch. Despite the haptic sense provides essential information about the spatial layout of peripersonal space, such as the size, shape, position, and orientation of objects within reach, it typically conveys information only within the scope of the body. The case of hearing is particularly interesting because the auditory sense is not only the main channel for providing distal information but also it might be superior to all other sensory alternatives because it provides spatial information in both active and passive conditions and it does not necessarily involve direct contact with objects [94, 95]. At the same time, the use of hearing to perceive distal information might be particularly difficult for visually impaired children because in this case, they do not have any sensory feedback about sonorous objects in the far space. On the contrary, the haptic-proprioceptive system can provide accurate spatial data only within the scope of the body itself [96], and therefore a blind person must actively move in the environment to sequentially touch all the stimuli embedded in space. Several factors may contribute to increasing the difficulty in interpreting such contrasting results. For example, many studies on spatial hearing have been conducted within the framework of broader research on cognitive and motor skills development [87, 97] and reaching mixing the motor and the perceptual component of the observed behavior [83, 98]. In addition, different methodological approaches and stimuli have been used to assess similar aspects of auditory spatial perception: for instance, studies performed on visually impaired children under 3 years of age do not employ psychophysical procedures but they frequently use the sound of familiar voices or toys to gather information about auditory localization abilities in blind children [97]. In addition, in some cases, sighted and blind groups of children are not perfectly matched for age range and sometimes use also adults as comparison [76]. Finally, the difference between early and later loss of vision has not been often considered: many studies mix data from children with no visual experience with those of children with partial visual experience in the first period of life [76]. Instead, it has been demonstrated that the onset of blindness has a strong impact on spatial performance in adulthood: for example, late blind individuals who lost vision later in life after a normal visual experience during the first year of life perform equally or even better than sighted participants in several auditory spatial tasks (1, 50, 83, and 300). To summarize, although compensatory mechanisms for spatial perception have been demonstrated in blind adults, it is not clear whether an early visual impairment might delay the development of special auditory spatial skills. The development of spatial cognition is strictly related to the development of social cognition: the ability to independently navigate and orient ourselves in space facilitates engagement in social interactions. Indeed, a delay in the acquisition of language, motor or cognitive skills can have a direct impact on a child's social competence (106, 109, and 246). More recent works highlighted that preschool-age children with visual impairments often have difficulties engaging in positive social interactions, making their assimilation into preschool

programs difficult. In fact, many do not display a full range of play behaviors

[99–103] and spend more time engaging in solitary play interacting more with adults than with their sighted peers [81, 87, 89, 102–107]. Considering that the interaction among peers is essential for the development of cognitive, linguistic, social, and playing skills [108], the aforementioned delay in the acquisition of social competence in visually impaired children gives rise to feelings of frustration, rather than self-efficacy and independence which characterize the social experience of typical children. Indeed, the lack of visual information during early infancy often constitutes a risk for the development of the personality and emotional competence [89]. Nonetheless, when assessing social competence in visually impaired people, some other factors resulting from the loss of vision should be taken into account. For example, it has been shown that parenting style influences the socio-emotional development of

**256**

sighted children [109–113] because parents represent the first influential setting that can produce appreciable differences in developmental outcomes in terms of psychological functions [114, 115]. Inconsistent, hostile and nonsensitive parenting behaviors have been associated with adjustment problems and social adversity during childhood [116, 117] and also with anxiety, depression, and other stress-related illnesses during adolescence [118, 119] and adulthood [120]. We speculate that a similar influence of parenting style holds also for blind children, especially because families of children with visual disabilities are more prone to experience various stressors such as concerns about the social acceptance of the child [121] and to face difficulties in initiating and sustaining social interactions [122], thus they might easily develop an overprotective behavior that negatively influences the social development of the visually impaired child. The negative effects of blindness on socio-emotional competence can be observed also in adulthood, with the impoverishment of the ability to perform everyday activities both in private settings like home and in public settings like workplace. Importantly, the decrease of functional abilities has been linked to the emergence of serious psychological problems in the blind population [123]. Indeed adults with visual impairments tend to feel more socially isolated and not properly supported compared to sighted individuals [123–126] and are at higher risk of developing depressive symptoms [105, 125, 127–131], principally because social competence depends on the ability to utilize visual cues [132]. Overall, several scientific findings suggest that visual impairments, especially if acquired later in life, can have profound consequences for the physical functioning, psychological wellbeing, and health service needs of older adults [133]. Consequently, early therapeutic interventions specifically focused on activities fostering the development of perceptual and motor abilities would improve the quality of life of children and adults with visual impairments. In the next section, we will present some tools developed to improve perceptual skills of visually impaired individuals and propose a new solution we recently developed for early intervention in visually impaired children.
