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Rett syndrome (RS) is a severe neurodevelopmental disorder that mostly affects females. It is characterized by a regression of motor, cognitive, linguistic, and social abilities and by an inappropriate and stereotypical use of the hands. The purpose of the current study was to explore the possibility of rehabilitating purposeful use of the hands and hand-eye coordination in individuals with this syndrome. G.P., a child affected by RS, received experimental, computerized visual-motor coordination training and a sensory-motor rehabilitative program specifically designed for her based on Piaget's (1937) theory of cognitive development. After 3 years of therapy, G.P. partially regained the use of her hands as an instrument of object knowledge and as a means of communicating with people.
Keywords: Rett syndrome; cognitive development; sensory-motor rehabilitation; visual-motor coordination; rehabilitative treatment; computerized training; severe cognitive retardation; stereotypical hand movements
Rett syndrome (RS) is a neurodevelopmental disorder that affects mainly females, with a prevalence of 1:10,000-20,000 (Percy, 2001). In this syndrome, seemingly normal infant development from 6 to 18 months is interrupted by a rapid or slow and gradual regression of cognitive development, including communication and socioemotional capacity, gross motor function, standing, ambulation, and transitional movements (Larsson & Witt Engerstrom, 2001; Rett, 1966). Children with RS show a very severe cognitive impairment, a loss of purposeful hand use, the appearance of stereotypical hand movements (hand washing and hand-mouthing movements), irregular breathing with apnea or hyperventilation, bruxism, sleep disturbances with unpleasant awakenings at night, frequent seizures, scoliosis, dystonia, ataxia, and autism (Kerr, 1992; Percy, Schanen, & Dure, 1998). Psychological features include anxiety and panic, occasionally self-injury (e.g., hand biting), reduced eye contact, and lack of interest in play (Coleman, Brubaker, Hunter, & Smith, 1988; Mount, Cass, & Charman, 2002; Mount, Hastings, Reilly, Cass, & Charman, 2001; Sansom, Krishan, Corbett, & Kerr, 1993). This pattern of symptoms can vary dramatically across individuals.
Recent studies have identified different mutations in the X-linked gene MECP2, encoding methyl-CpG binding protein 2 in several cases of RS. This suggests the genetic involvement of the Xq28 region of the X chromosome in this syndrome (Amir et al., 1999; Percy, 2001; Schanen, 1999; Willard & Hendrich, 1999). However, mutations in MECP2 are responsible for only 75% of cases RS submitted to genetic screening; 25% of cases are negative on the same test, suggesting that other genes may be involved in RS phenotype (Van Den Veyver, Subramanian, & Zoghbi, 1998).
Neuropathology studies show decreased brain growth beginning at 3 to 4 months, decreased size of dendrites of pyramidal neurons in the frontal and temporal lobes, and abnormalities in substantia nigra. This suggests deficient synaptogenic development, probably starting before birth (Armstrong, 1995; Belichenko, Hagberg, & Dahlstrom, 1997; Dunn, 2001; Kitt & Wilcox, 1995). Volumetric brain magnetic resonance imaging (MRI) studies reveal a selective reduction in gray and white matter volumes in prefrontal, posterior frontal, and anterior temporal regions (Percy et al., 1998; Subramanian, Naidu, & Reiss, 1997), along with general reduced thickness of the cortex (Naidu et al., 2001). However, brain weight does not continue to decrease with age.
According to diagnostic criteria (Hagberg, Goutieres, Hanefeld, Rett, & Wilson, 1985; Hagberg, Hanefeld, Percy, & Skjeldal, 2002; Trevathan et al., 1988), development is within the normal range in the first months of life. However, there is increasing agreement that subtle abnormalities (such as lack of vocalizations, communicative gestures, nonverbal play skills, and words) should be considered as early predictors of RS (Charman et al., 2002; Leonard & Bower, 1998). A developmental regression frequently occurs between 12 and 18 months of age, more rarely before 6 months or after 36 months. Age of regression may be considered a potential index of severity of neurological insult (Charman et al., 2002). A negative prognosis for individuals with RS relates to the severity of mental retardation. Individuals with RS generally achieve an average global cognitive development of 9 months, and their communication and verbal comprehension abilities are around 4 to 11 months of mental age. However, daily living abilities correspond to a mental age of 12 to 14 months (Perry, 1991). The loss of various skills is persistent and subtle. People with RS can grow old, but they are unable to regain hand ability or language (American Psychiatric Association, 1994).
Two conclusions may be drawn on the pathogenic process of this syndrome:
1. Stability in brain size and absence of markers for degenerative disorders support the idea that the decreased brain size in RS results from a halt in brain development (Armstrong, 2001).
2. Pathological process in RS is not a mere development arrest because it involves a selective change in specific brain regions, such as motor areas and speech areas 4, 45, 22, and 40 (Belichenko & Dahlstrom, 1995), during a critical period of brain development, thus depriving the brain of its capacity to monitor speech and hand use. In conclusion, the brains of individuals with RS could be selectively immature and malformed (Armstrong, 2001).
Currently, there are no available therapies that radically change the course and the natural evolution of RS (Zwaigenbaum & Szatmari, 1999). Interventions are generally aimed at preserving physical and psychosocial functioning, enhancing quality of life, and providing education and support to families. Efficacy of the adopted therapies is not well documented, most findings being based on single case studies and individual experiences rather than controlled experimental studies (Zwaigenbaum & Szatmari, 1999). Children with RS are frequently placed in special education programs and receive assistance, such as behavior modification, drug therapy, and other types of treatments, to encourage acquisition, or reacquisition, of basic adaptive skills (e.g., expressing preferences, self-feeding, and achieving various motor skills).
In the past few years, along with genetic studies, there has been an increasing interest in the clinical and rehabilitative aspects of this syndrome, particularly in the cognitive, behavioral, and emotional development of individuals with RS. At the moment, some therapeutic approaches are under investigation. On one hand, efforts are being made to develop genetic (Johnston, Jeon, Pevsner, Blue, & Naidu, 2001; Migeon, Dunn, Thomas, Schmeckpeper, & Naidu, 1995; Naidu, 1997) and pharmacological therapies aimed at controlling seizures, respiratory deficits, and sleep disorders and improving attention span, eye contact, and motor abilities (Wenk et al., 1993; Wenk, Naidu, Casanova, Kitt, & Moser, 1991). On the other hand, different educational approaches, including music therapy (Yasuhara & Sugiyama, 2001), hydrotherapy (Bumin, Uyanik, Yilmaz, Kayihan, & Topcu, 2003), educational proposals (Budden, 1997), and instrumental interventions for reducing stereotypical behavior (e.g., hand splinting to decrease hand mouthing; Naganuma & Billingsley, 1988; Sharpe, 1992), are being proposed.
The main goals of music therapy are to develop potential communication and attention, to motivate, and to promote functional hand use and social abilities. Single case studies (Wigram, 1991; Wigram & Lawrence, 2005) or on small groups (three children: Yasuhara & Sugiyama, 2001) have shown a temporary interruption of the stereotypic movements, possibly due to the soothing effects of the music. Nevertheless, these positive results seem to be confined to the therapeutic setting only and do not show a long-lasting and generalized effect on daily life.
Another approach that has been used in treating individuals with RS is hydrotherapy. It seems to improve gross motor abilities, in particular spontaneous movements, and the action of warm water favors muscle relaxation and decreases body tension. However, positive effects seem to only last up to 8 weeks after the therapeutic sessions. Only one study reports the use of hydrotherapy on this syndrome (Bumin et al., 2003); this calls for further investigation on a larger sample of participants.
Other studies reported the use of horseback riding in addition to motor therapy to improve balance and children's emotional states (Hunter, 1999; Lindberg, 1991). Scientific studies have yet to test the effectiveness of this approach.
Occupational therapy is used to promote and increase purposeful use of the hands in daily life activities. This therapy employs assistive technology devices, such as pointers and switches that activate toys or a simple cause/effect computer activity (Hanks, 1986; Sullivan, Laverick, & Lewis, 1995). Although many emphasize the teaching of skills involved in daily routines, there have been few studies published on the use of occupational therapy with individuals with RS.
Another therapeutic approach is based on the use of Augmentative and Alternative Communication (AAC; Sigafoos & Woodyatt, 1996), which relies on comprehension ability as well as the ability of children with RS to communicate with eye gaze. This approach helps bypass communication deficits and stimulate interaction. However, it has two main drawbacks. First, the meaning given to the child's gaze as a means of indicating and …