Marja-Leena Haapanen

Dysfunction of the auditory cortex persists in infants with certain cleft types

Language and learning disabilities occur in almost half of individuals with oral clefts. The characteristics of these cognitive dysfunctions vary according to the cleft type, and the mechanisms underlying the relation between cleft type, cognitive dysfunction, and cleft‐caused middle‐ear disease are unknown. This study investigates preattentive auditory discrimination, which plays a significant role in language acquisition and usage, in infants with different cleft types. A mismatch negativity (MMN) component of brain evoked potentials, which indexes preconscious sound discrimination, and brain responses to rare sine‐wave tones were recorded in 12 healthy infants and 32 infants with oral clefts at the ages of 0 and 6 months. Infants with clefts were subdivided into two categories: those with cleft lip and palate (CLP) (n=11 at birth, n=6 at the age of 6 months) and those with cleft palate only (CPO) (n=17 at birth, n=8 at the age of 6 months). At both ages, brain responses to rare sounds tended to be smaller in both cleft subgroups than in healthy peers. However, in the latency range of 300 to 500 ms, the MMN was significantly smaller in infants with CPO. In infants with CLP, the MMN was comparable to that of healthy infants. Differences in auditory discrimination between infants with CLP and CPO, as reflected by MMN, were detectable at birth and persisted into later infancy. This pattern parallels known behavioural differences between children with these cleft types. Brain responses to rare sounds, in contrast, had no differentiative power with respect to the cleft type.

The first neurophysiological evidence for cognitive brain dysfunctions in children with Catch

CATCH syndrome, caused by a microdelection in chromosome 22, is characterized by cleft palate and cardiac anomalies. The majority of these children also have learning difficulties or speech and language deficits. These problems are often due to the dysmorphology of the articulatory system. In the present study, the duration of auditory sensory memory, which is of central importance to speech perception and understanding, was investigated. As a research method we used mismatch negativity (MMN), an attention independent eventrelated potential, which provides an objective electrical index of auditory sensory memory. The present data suggest that the duration of this memory span is considerably shorter in 6–10-year-old children with CATCH than in healthy controls. Thus, the language-related problems encountered in children suffering from CATCH syndrome are likely to be caused also by CNS dysfunctions.

Cortical auditory dysfunction in children with oral clefts: relation with cleft type

OBJECTIVE Up to 46% of individuals with oral clefts suffer from language-learning disabilities. The degree of these disabilities varies according to cleft type. The pathogenesis of cognitive malfunctioning or its relationship with cleft type is not known. We investigated persistence of auditory short-term memory (STM) that is implicitly involved in language-specific perception in children with clefts, grouped using fine-graded cleft classification. METHODS Cortical evoked potentials were recorded in 78 children with non-syndromic oral clefts and in 32 healthy peers. A mismatch negativity (MMN) potential that indexes preattentive detection of change in auditory input was obtained in response to tone sounds. In order to test durability of short-term memory traces, sounds were presented with three stimulation rates. RESULTS With slowest stimulation, MMN amplitudes were reduced in cleft children as compared to the healthy peers (P < 0.00065). Only cleft-lip children did not significantly differ from controls. Among isolated palatal clefts, the more posteriorly delimited the cleft was, the smaller was the amplitude of MMN. MMNs of smallest amplitudes were obtained in the subgroup of complete unilateral cleft of lip and palate. CONCLUSIONS Reduced MMN amplitudes, found in cleft children, imply deficiency in auditory STM trace maintenance. This dysfunction is likely to contribute to their language and learning disabilities. The MMN diminution with shorter/more posterior clefts suggests that differences in auditory cortex function are one of the underlying mechanisms of the cleft type-malcogniton association.

Correlation between the age at repair and speech outcome in patients with isolated cleft palate.

The effect of the age at primary palatal repair on the speech of 3-year old children with isolated cleft palate was assessed. The group comprised 108 consecutive children whose palates were repaired at the mean ages of 12.9 (n = 45), 18.5 (n = 18) and 22.1 months (n = 45). Signs of cleft palate speech and the degree of speech impairment were recorded. The signs sought were: hypernasality, audible nasal air emission, and misarticulations associated with velopharyngeal insufficiency. The speech impairments were subdivided into three categories by combining the signs of cleft palate speech. The results showed that children who were operated on at the age of about 12-18 months were significantly better speakers than those operated on later. Of these 46 were rated as normal or practically normal speakers (73%), compared with 10 of the children who had their repairs delayed until about 22 months (22%). As a result of the speech evaluations, it was predicted that 5 (11%), 0 and 21 (47%) children in the early, middle, and late closure groups, respectively, required secondary surgery to eliminate signs of cleft palate speech associated with velopharyngeal inadequacy. The numbers who had secondary surgery were 4, 0 and 18 in the three groups.

Brain dysfunction in neonates with cleft palate revealed by the mismatch negativity.

OBJECTIVES Our recent studies have demonstrated that the brains automatic change-detection response, the mismatch negativity (MMN) of the event-related brain potential (ERP), is significantly attenuated in school-age children with CATCH syndrome and in children of the same age with cleft palate but without the CATCH syndrome. Among other problems, various kinds of learning difficulties are commonly reported in these patient groups. The present study aimed at investigating whether the MMN is attenuated already in newborns with cleft palate compared with healthy controls. METHODS Stimuli of 1000 Hz were presented frequently and 1100 Hz infrequently to 9 neonates with cleft palate and to 8 healthy controls. Infrequent 1100 Hz stimuli elicited a prominent MMN in all of the healthy children, but only in 3 of the 9 infants with cleft palate. RESULTS A significant difference in the mean amplitudes of responses to deviant tones between the healthy and cleft palate neonates was found. CONCLUSIONS MMN may indicate brain dysfunctions long before they have manifested themselves in cognitive disabilities, which would enable one to identify the infants with an elevated risk and to start their rehabilitation much earlier than before.

Velopharyngeal function from the age of three to eight years in cleft palate patients

The purpose of this investigation was to study changes of velopharyngeal function between the ages of 3 and 8 years. The subjects were 65 (30 girls and 35 boys) Finnish-speaking non-syndromic children with isolated cleft palate (CP, n = 35) and with unilateral cleft lip and palate (UCLP, n = 30) operated primarily at the age of 1.0–2.0 years. Before the age of 8 years, 16 children required velopharyngoplasty (VPP, ad modum Hoenig). The children were followed up for speech at the age of 3, 6 and 8 years. The perceptual speech characteristics nasal air emission, hypernasality, weakness of pressure consonants and compensatory articulations were registered. Indications for a velopharyngeal flap (by VPP) were identified on the basis of perceptual speech characteristics and confirmed by instrumental examinations. The results indicated that the method and timing of primary palatoplasty and sex did not correlate with the quality of velopharyngeal function. It was good both in children treated conservatively or with VPP at the age of 8 years. The children with a flap required speech therapy significantly more often than other children. No child with VPP and only 12% of the children without VPP had simultaneous nasal air emissions and hypernasality. Compensatory articulation was completely eliminated and weakness of pressure consonants was diagnosed only in 1 child without VPP. The CP children required significantly more often a velopharyngeal flap than the UCLP children. In conclusion, the CP and UCLP children develop a similar velopharyngeal function but in a different way.

Mismatch negativity (mmn) as an index of auditory sensory memory deficit in cleft-palate and Catch syndrome children

OUR recent study demonstrated with the brains automatic change-detection response, the mismatch negativity (MMN) of the event-related potentials (ERPs), that the duration of auditory sensory memory is significantly shorter in school-age children with CATCH syndrome than in healthy age-matched controls. One of the haracteristic symptoms of this syndrome, caused by a microdelection in chromosome 22, is cleft palate. The most common problems in these children, however, are learning difficulties and, according to our results, it is likely that these problems are not due to the dysmorphology of peripheral speech mechanisms only but are also caused by CNS dysfunctions. In the present study we show with MMN that auditory sensory memory is also shortened in school-age children with cleft palate but without the ATCH syndrome. It has been shown in previous studies with neuropsychological tests that although children with cleft palate have language and learning-related problems these difficulties are usually less severe than those of CATCH children. Likewise the present study demonstrates that the auditory sensory memory trace seems to decay more rapidly in CATCH children than in children with cleft palate.

Velopharyngeal Function in Cleft Patients Undergoing Maxillary Advancement

Maxillary advancement may result in movement of the posterior border of the hard palate with its soft palate attachment, which may cause impairment of velopharyngeal (VP) function. We examined VP function before and after Le Fort I osteotomy in 15 cleft lip and palate patients. The extent of maxillary advancement was measured by means of standard cephalometric radiographs taken before and after the operation. VP function was evaluated in terms of perceptual speech assessments, pressure-flow data and nasalance scores preoperatively and 2, 6 and 12 months after the operation. The results showed that maxillary advancement resulted in impairment of VP function in 4 (27%) of the patients.

Auditory sensory impairment in children with oral clefts as indexed by auditory event-related potentials.

Children with nonsyndromic oral clefts and with the CATCH 22 syndrome (acronym for cardiac defects, abnormal faces, thymus hypoplasia, clefts, and hypocalcemia) display a range of language and learning disabilities, the neurofunctional bases of which are not yet understood. This review summarizes recent event-related brain potential (ERP) studies on central auditory processing in infants and children with different cleft types and presents an effort to integrate these ERP and earlier behavioral findings into a workable hypothesis on the mechanisms of cognitive impairment in the oral cleft population. The encoding of the acoustic sound features and the functioning of auditory sensory memory (ASM) were studied by recording cortical auditory ERPs. Tapped were two ASM functions: tone pitch discrimination and the duration of sensory memory for tone pitch. In infants with cleft palate, tone pitch discrimination was impaired at birth and at 6 months of age. In infants with cleft lip and palate, no ASM impairment was detected at either age. In school-aged children with clefts and CATCH 22 syndrome, the discrimination of tone pitch was intact under optimal stimulation conditions. However, in these children, shortened duration of ASM was observed, with the magnitude of its shortening covarying with cleft type and being most pronounced in children with CATCH 22 syndrome. The different types of ASM dysfunction found in children with different cleft types could not be accounted for by the peripheral hearing deficits. The relation between ASM dysfunction and known behavioral cognitive disability profiles in children with different cleft types suggests that ASM is implicated in language disabilities of children with oral clefts. Furthermore, it appears that the ASM impairment and oral clefting are linked in a comorbid fashion.

Cephalometric pharyngeal changes after Le Fort I osteotomy in patients with unilateral cleft lip and palate

Pharyngeal changes after Le Fort I osteotomy were evaluated cephalometrically in 37 patients (27 M, 10 F; mean age 23.8 years) with unilateral cleft lip and palate (UCLP). Seven patients had previously undergone velopharyngeal (VPP) flap surgery to improve speech. One year postoperatively the patients without previous VPP showed a significant change (55%-85% of the surgical change) in the upper and lower sagittal depth of the nasopharyngeal airway, but not in the depth of oropharyngeal airway, length of soft palate, or position of hyoid bone. No significant changes were observed between 6 months and 1 year postoperatively. Mean surgical horizontal advancement was 4.7 mm and the mean vertical lengthening 4.7 mm anteriorly and 1 mm posteriorly. There was a correlation between the amount of horizontal advancement and the amount of change in the nasopharyngeal airway. The patients with previous VPP showed significant postoperative change (85% of the surgical change) only in the lower nasopharyngeal airway, although their surgical advancement was similar to that without previous VPP. Patients with previous VPP showed significantly smaller depths of upper nasopharyngeal airway postoperatively than the patients without previous VPP. Five patients (13%) needed VPP after the osteotomy. There was no difference in the nasopharyngeal airway in the patients with VPP after the osteotomy when compared to those without, but they seemed to have shortest maxillary lengths and largest mean surgical changes vertically both anteriorly (5.5 mm) and posteriorly (2.3 mm). Moderate maxillary advancement in UCLP patients results in significant changes in the nasopharyngeal airway.