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Biomedical subjects

Makiko Kaga

Publications and source records attributed to Makiko Kaga.

At least 19 recordsLinked to original sources
PubMed2006

Characteristic findings of auditory brainstem response and otoacoustic emission in the Bronx waltzer mouse.

Auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) were evaluated serially from 1 to 22 months in Bronx waltzer homozygotes (bv/bv), heterozygotes (+/bv) and control (+/+) mice, which were differentiated by means of PCR of marker DNA (D5Mit209). The wave IV threshold of the click-evoked ABR was higher than the DPOAE threshold with the DP growth method in each bv/bv, although the two thresholds were almost the same in the +/+ group. The DP value at 2f(1) - f(2) in the bv/bv showed an apparent decrease at 2 to 3 months of age with 80 dB SPL stimulation using f(2) frequency 7996 Hz and frequency ratio f(2)/f(1) = 1.22, compared to control or heterozygote mice. It was characteristic that the 2f(2) - f(1) DP signal-to-noise ratio (SNR) value was more preserved from 80 to 60 dB SPL than the 2f(1) - f(2) DP value at f(2) frequency 7996 Hz in most bv/bv, however, control mice showed almost the same levels of 2f(1) - f(2) and 2f(2) - f(1) SNR value at both f(2) frequencies of 6006 and 7996 Hz. The preservation of a substantial 2f(2) - f(1) DP suggested that it would be generated basal to the primary-tone place on the basilar membrane and there might be a reflection of the unique function of the remaining outer hair cells in the Bronx waltzer mice. These findings suggest that combination of ABR with DPOAE could offer useful information about differentiating the mechanism of hair cell dysfunction of the hereditary hearing impairment in the clinical fields.

Acoustic Stimulation↗
PubMed2006

[Developmental changes of N400 event related potential of a semantic category decision task and modality specific findings in patients with developmental dyslexia].

We investigated modality-specific changes in N400 event related potential using a semantic category decision task in 38 control subjects and 8 patients with developmental dyslexia. In control children under 10 years old, auditory N400 showed a negative deflection over the fronto-centro-parietal areas with substantial amplitude. Control children over 10 years old showed a similar pattern of N400 waves in a visual and an auditory-visual modality, suggesting that the visual modality becomes dominant in the late teens. Dyslexic children showed more errors on a visual than auditory modality task with poorer N400 waves for visual stimuli. However, peak latencies of N400 in an auditory-visual modality were almost the same for auditory stimuli in control children. Differences in the N400 pattern in children might reflect the fragility and reversibility of the semantic processes through stimulus modalities.

Adolescent↗
PubMed2005

Fluctuating hearing loss, episodic headache, and stroke with platelet hyperaggregability: coexistence of auditory neuropathy and cochlear hearing loss.

We encountered a 10-year-old girl with fluctuating sensorineural hearing loss, episodic headache, and white matter stroke. Strenuous exercise, febrile illness, and general anesthesia all temporarily worsened hearing. Audiologic findings were asymmetric: left-sided retrocochlear dysfunction consistent with auditory neuropathy contrasted with cochlear hearing loss in the right ear. Platelets obtained during a headache-free period showed excessive responsiveness to collagen in vitro, while episodic elevations of thromboxane B(2) and thrombin-antithrombin III complex were noted in blood sampled during headache. Treatment of hyperaggregability of platelets with aspirin and antioxidant vitamins relieved headache, while adenosine triphosphate administration improved hearing thresholds. In this patient, hearing impairment and white matter strokes appeared to respectively related to impaired blood flow to the cochlea and white matter caused by platelet dysfunction triggered by physiologic stresses.

Adenosine Triphosphate↗
PubMed2005

Natural history of X-linked adrenoleukodystrophy in Japan.

The natural history of X-linked adrenoleukodystrophy (ALD) was investigated, using a nation-wide retrospective study based on a questionnaire survey. The data on 145 patients, including 46 patients with the childhood cerebral form, 39 with adrenomyeloneuropathy (AMN), 33 with the adult cerebral form, 14 with the adolescent form and 13 with the olivo-ponto-cerebellar (OPC) form, were analyzed. Initial symptoms of the childhood cerebral form were intellectual (n=16) and visual (n=11) disturbances, whereas those of AMN were gait (n=37) and sensory (n=3) disturbances; the adult cerebral form, psychic (n=19) and gait (n=11) disturbances; the adolescent form, visual n=5) and gait (n=4) disturbances; and the OPC form, gait (n=9) disturbance. Patients with onset under the age of 8 years progressed more rapidly than those over 8 years old. Visual, hearing, gait and swallowing disturbances progressed more slowly in the older group. About half of AMN patients showed cerebral involvement about 10 years after onset. Patients with the OPC form also showed a similar progression. A Kaplan-Meier plot clarified the characteristic pattern of progression of neurological symptoms in each phenotype. These finding will improve the understanding of the natural history of X-linked ALD and will provide a basis for the evaluation of specific treatment for X-linked ALD.

Adolescent↗
PubMed2005

Sleep-related nighttime crying (yonaki) in Japan: a community-based study.

OBJECTIVE: To examine factors associated with the phenomenon of yonaki, or sleep-related nighttime crying (SRNC), in Japanese children METHODS: A cross-sectional design incorporating parental self-report was used to investigate relationships between developmental, psychologic, and constitutional/physiological factors in the incidence of SRNC. Participants were the parents of 170 infants, 174 toddlers, and 137 children at a well-infant clinic in Tokyo, Japan. RESULTS: The lifetime incidence rates of SRNC were 18.8% (infants), 64.9% (toddlers), and 59.9% (children). At all ages, children were most likely to cosleep with their parents; however, infants with reported SRNC were found to cosleep more frequently, whereas infants without SRNC were more likely to sleep in separate, child-dedicated beds. Toddlers with frequent SRNC were more likely to have irregular bedtimes and to have nonparental day care than were those without SRNC. Preschoolers who typically slept 9.5 to 10.5 hours per night were less likely to report SRNC than were children with longer or shorter nighttime sleep durations. In all groups, children with frequent SRNC were more likely to suffer from chronic eczema, and toddlers and preschoolers with SRNC exhibited bruxism more frequently. CONCLUSIONS: The traditional Japanese arrangement of cosleeping represents an environment in which parents are readily accessible to children during waking episodes. Physical proximity to the parents in infancy, but not at other ages, is associated with SRNC. The higher incidence of bruxism, chronic eczema, and day care use among children with frequent SRNC supports the hypothesis that nighttime anxiety may promote SRNC.

Bruxism↗
PubMed2005

[Early diagnosis and early intervention in children with developmental disorders: introductory remarks].

Developmental disorders such as mental retardation, language disorders, autistic disorders, learning disorders, attention deficit/hyperactivity syndrome and conduct disorders are an important part of our daily practice in child neurology. Early diagnosis and early or timely intervention in these kinds of developmental disorders were stressed and family support in child-rearing was emphasized in this symposium. In addition to the above, sleep disorders in developmental disorders were discussed.

Child↗
PubMed2005

["Early" diagnosis and "early" intervention in children with mental retardation--when is early enough to diagnose them?].

Patients with mental retardation (MR) cannot always be diagnosed accurately by physicians who are specialized in child neurology and/or developmental disorders at their first visit to the clinic. Precise examination such as psychological tests and chromosomal analysis are often necessary to diagnose them. Some patients with autistic disorders without MR often are misdiagnosed as having MR. Patients with mild to moderate MR are sometimes diagnosed late in their late teens or twenties. Timely diagnosis and timely/continuous intervention is more important than early diagnosis and early intervention for the mentally retarded.

Adult↗
PubMed2005

[Assessment of chromosome and gene analysis for the diagnosis of the fragile X syndrome in Japan: annual incidence].

We assessed the utilization of diagnostic analyses for fragile X syndrome by a mail-in questionnaire on 1) the number of patients analyzed and diagnosed with the syndrome in the past year, 2) types of diagnostic analyses used, 3) clinical features that made physicians to decide analyses, 4) purpose of analyses, and 5) informed consent for analyses. Facilities for the mentally handicapped, as well as hospitals and physicians specialized in genetics, completed our questionnaire. Among 101 responders, total of 543 cases underwent analyses. Nine cases (including 3 cases over 20 years old) were finally diagnosed in a year. The rate of positive findings was 0.6% for chromosomal analyses, and 8% for gene analyses. Physicians dicided to make analyses based on clinical features such as mental retardation, characteristic face, and autistic features, in order to find the cause (s) of the subjects' condition. For gene analyses, more than a half of physicians obtained a form of informed consent. Specialists should have interest in this syndrome because the analyses identified new adult cases. Establishment of a guideline for diagnosis of this syndrome requires gene analyses based on evidence and informed consent.

Autistic Disorder↗
PubMed2004

The neural network for the mirror system and mentalizing in normally developed children: an fMRI study.

We performed fMRI measurements in normal children to clarify which cortical areas are commonly involved in the mirror system (MS) and mentalizing, which areas are specific for mentalizing, and whether children have the same neural networks for MS and mentalizing as adults. Normal children had the same neural networks for the MS and mentalizing as adults. Common activations were found in the superior temporal sulcus and the fusiform gyri, whereas mentalizing specific activation was found in the medial prefrontal, temporal pole and the inferior parietal cortices. We suggest that mentalizing might evolve from a capacity to detect the motion of agents and to infer intentions. Further, mentalizing might require self-perspectives.

Adolescent↗
PubMed2004

[Serial median nerve SEPs and SSEPs in patients with West syndrome].

We studied serial median nerve somatosensory evoked potentials (SEPs) and short latency somatosensory evoked potentials (SSEPs) in 17 patients with West syndrome. Four of the 7 patients with absent SEPs in the initial examination showed recognizable SEPs in the follow-up studies, associated with improvement of electroencephalogram (EEG). This indicated that SEPs were variable with condition of epilepsy and lack of initial SEPs was not always a poor prognostic factor for seizure control and developmental outcome. Persistent lack of SEPs, however, indicated poor outcome of seizures, EEG and development. Central conduction time in SSEPs did not correlate with seizure or developmental outcome.

Child, Preschool↗
PubMed2004

[Guidelines for medical examination of children with mental retardation in pediatric clinics which are specialized for developmental disorders--recommendation based on the current selection and usefulness of diagnostic examinations for children with mental retardation and/or pervasive developmental disorder].

We assessed the present status of choice and usefulness of medical examinations of children with mental retardation (MR) and/or pervasive developmental disorder (PDD). Children with severe MR received more examinations than those with mild MR. Many abnormal findings were demonstrated by MRI in cases of severe MR. Cases of PDD without MR rarely showed abnormal results. Cases of PDD with MR underwent fewer examinations, but showed more abnormal results. We presented guidelines regarding medical examinations for children with MR in pediatric clinics which are specialized for developmental disorders, including psychological tests, hearing tests, EEG, genetic tests and neuroimaging. Physicians should select appropriate medical examinations based on evidence. The goal of testing is to provide useful information concerning medical treatment, therapeutic rearing, and education, and to support patients and their families in cooperation with relevant facilities.

Child↗
PubMed2004

[Clinical neurophysiological study of verbal and non-verbal sound perception: normal development of P300 event-related potential to different sound stimuli].

Developmental changes of P300 event related potential were evaluated in healthy children and adults aged from 7 to 29 years old, adopting 2 pairs of oddball stimuli: a non-verbal sound (tone burst: TB) pair and a verbal sound (VS) pair. P300 was evident for the target stimuli. In adult subjects, P300 was dominant at Pz for both stimuli. Peak latency of P300 was significantly longer for VS than for TB in both groups. P300 amplitude of the child group was higher than that of the adult group, however, there was no difference in P300 amplitude between stimuli conditions. Developmental changes of P300 from each stimuli condition were simulated by a quadratic equation. The age showing the shortest P300 peak latency was younger for TB (20.3 years) than for VS (23.6 years). The P300 peak latency reduced around 10 years old more rapidly for VS than for TB. In conclusion, there was no difference of the dominancy of P300 between the stimuli. The developmental changes of P300 were regulated by several components of the sound stimuli, such as their frequency.

Acoustic Stimulation↗
PubMed2004

[Assessment of social networks between developmental physicians and welfare facilities/specialists for children with intellectual disabilities in Japan].

The social networks between Japanese child neurologists and welfare facilities/specialists for children with mental retardation (MR) were assessed. A total of 113 physicians answered our mail-in questionnaire. Most of the doctors had various connections with nursery homes for children with MR or severe motor and intellectual disabilities (SMID) and with public health centers, and often collaborated with teachers of schools and kindergartens. On the other hand, most physicians had little relation with residential and vocational facilities for adults with MR, and with specialists in residential or community care. There was a statistical correlation between the number of facilities or collaborated specialists and the number of persons seen by each physician; however, the physicians' experience and affiliations had no relation. In view of 'social participation', physicians who usually see children with developmental disorders can play an important role in decision making of their life-style with their families.

Child↗
PubMed2004

[Visual perception of Kanji characters and complicated figures. Part 3. Visual P300 event-related potentials in patients with attention deficit/hyperactivity disorders].

In order to evaluate visual perception, the P300 event-related potentials (ERPs) for visual oddball tasks were recorded in 11 patients with attention deficit/hyperactivity disorders (AD/HD), 12 with mental retardation (MR) and 14 age-matched healthy controls. With the aim of revealing trial-to-trial variabilities which are neglected by investigating averaged ERPs, single sweep P300s (ss-P300s) were assessed in addition to averaged P300. There were no significant differences of averaged P300 latency and amplitude between controls and AD/HD patients. AD/HD patients showed an increased variability in the amplitude of ss-P300s, while MR patient showed an increased variability in latency. These findings suggest that in AD/HD patients general attention is impaired to a larger extent than selective attention and visual perception.

Attention↗
PubMed2004

[Abnormal findings of dichotic listening test in patients with childhood adrenoleukodystrophy].

Ten Japanese boys with childhood-onset adrenoleukoqdystrophy (ALD) were evaluated with dichotic listening test (DLT). Six cases showed abnormal findings especially of laterality index (L.I.) calculated from the score of each ear. Some of them showed no abnormal findings with other auditory examinations containing auditory brainstem responses (ABR). One patient showed abnormal L.I. of DLT at an early stage. The abnormality of laterality index was similar to the so-called "strong left-ear suppression" in patients who underwent callosotomy. Although all of these six patients had a high signal lesion at the splenium of the corpus callosum in a T3-weighted MRI sequence, it was difficult to evaluate the width of demyelinated area. DLT could detect the early damage of connecting fibers mediating inter-hemispheric transfer of auditory information, and might be a useful method for evaluating the cerebral function of auditory processing in patients with childhood ALD.

Adolescent↗
PubMed2004

[Japanese physicians'attitude for utilization of social support services for persons with intellectual disabilities].

We assessed physicians'attitude for the utilization of social (medical, educational, and financial) support services for persons with intellectual disabilities supplied by the Japanese government. A total of 113 physicians specializing in pediatric neurology answered our mail-in questionnaire. Medical care benefits for psychiatric outpatients and short-time stay were the most common services utilized. Whereas most physicians used various public support services regardless of their experience and affiliations, the selection of services by an individual physician correlated with the number and state of patients they usually cared. Physicians were less familiar with the services regarding residential or community care and advocacy. Knowledge of the specialists on each service will enrich assistance appropriate to the life styles of each patient with intellectual disabilities.

Child↗