Palliative surgeries for refractory epilepsy include
Palliative surgeries for refractory epilepsy include vagus nerve stimulation and corpus callosotomy. Among 220 individuals with CDD with parent-entered data, 17% had a vagus nerve stimulation implanted and 69% of parents reported reduced seizure frequency. These data are consistent with a case report of benefit and Boston Children's Hospital COE reports improvement in five of six individuals (Olson et al., unpublished data, 2018). There are no reports of response to corpus callosotomy in the literature and limited experience in the COEs but no response in one individual (Olson et al., unpublished data, 2018). In the International CDKL5 Disorder Database at least seven of 10 individuals had some improvement in seizures after corpus callosotomy of whom two had a longer than six-month glycosylase inhibitor of seizure freedom (Leonard et al, unpublished data, 2018).
Development All individuals with CDD have severe global developmental delays and intellectual disability, although regression is rare except with worsening of seizures or epileptic encephalopathy.13, 15, 17, 18, 19, 67, 68, 69, 70 Individuals with CDD achieve gross motor milestones at a slowed pace compared with normal. Assessing in girls for whom there are more data, independent walking was attained by 22% to 23%, raking grasp by 49% by five years, and pincer grasp by only 13% at any time point.34, 68 Using time to event analysis, just under half of individuals could babble by six years (43/97 or 44%), and just under a quarter of subjects could speak single words by age seven years (17/105 or 16%). Spoken language, signs, or abstract symbols were produced by 26% of females with CDD (0% of males) and 7.5% of females with CDD spoke in sentences. The most common communication modalities were body language, facial expressions, and simple sounds and gestures. Use of nonverbal communication devices such as switches and eye gaze technology-based communication is often limited by cortical visual impairment, but can be used by some individuals with CDD (Olson et al., unpublished data, 2018). Autistic features are commonly reported but autism spectrum disorder is infrequently diagnosed because of global developmental impairments.2, 15, 17, 18, 19, 20, 70, 71, 72 A diagnosis of autism spectrum disorder has been observed rarely in the COEs. Overall, males were reportedly more severely affected than females, although our COE experience does not suggest a striking difference in phenotype (Olson et al., unpublished data, 2018).13, 34 Males can have a milder phenotype (Olson et al., unpublished data, 2018).
Movement disorders Hand stereotypies were reported in 80% of individuals, and 59% of females and 12.5% of males achieve functional hand use, which may be limited by stereotypies. The hand stereotypies that we have observed are more consistent with self-stimulatory behavior versus the type of hand stereotypies observed in Rett syndrome (Olson et al., unpublished data, 2018). Repetitive leg crossing is also commonly observed (Olson et al., unpublished data, 2018). We lack data on other movement disorders although the COEs have observed episodic or persistent, and occasionally severe, choreoathetosis, akathisia, dystonia, and parkinsonian features (Olson et al., unpublished data, 2018). Movement disorders may worsen when individuals achieve temporary seizure control (Olson et al., unpublished data, 2018). At times this may be attributed to polytherapy with antiseizure medications, improving with reduction in number of antiseizure medications (Olson et al., unpublished data, 2018).
Physical examination findings Hypotonia is a nearly universal feature.14, 15 Cortical visual impairment is common, occurring in at least 75% of individuals (Olson et al., unpublished data, 2018), with reports of poor eye contact and lack of visual tracking with an otherwise normal ophthalmologic examination.15, 16, 17, 19, 34, 69, 70 Rotatory and horizontal nystagmus, dysconjugate gaze, abnormal fixation, and reduced or absent optokinetic nystagmus response are features observed in individuals with visual impairment. Microcephaly and deceleration of head growth occurs in <10% of individuals.13, 15, 17, 18, 19, 20, 69, 70 Subtle dysmorphic features include deep set eyes, broad or high forehead, prominent lips, deep philtrum, puffy phalanges, and tapered fingers.13, 15, 19, 67, 70, 71 Movement disorders have also been observed as mentioned previously.