Biomedical subjects

K Y Chee

Publications and source records attributed to K Y Chee.

9 recordsLinked to original sources

PubMed2000

A functional neuroanatomy of tics in Tourette syndrome.

BACKGROUND: Tics are involuntary, brief, stereotyped motor and vocal behaviors often associated with irresistible urges. They are a defining symptom of the classic neuropsychiatric disorder, Tourette syndrome (TS), and constitute an example of disordered human volition. The neural correlates of tics are not well understood and have not been imaged selectively. METHODS: Event-related [(15)O]H(2)O positron emission tomography techniques combined with time-synchronized audio and videotaping were used to determine the duration of, frequency of, and radiotracer input during tics in each of 72 scans from 6 patients with TS. This permitted a voxel-by-voxel correlational analysis within Statistical Parametric Mapping of patterns of neural activity associated with the tics. RESULTS: Brain regions in which activity was significantly correlated with tic occurrence in the group included medial and lateral premotor cortices, anterior cingulate cortex, dorsolateral-rostral prefrontal cortex, inferior parietal cortex, putamen, and caudate, as well as primary motor cortex, the Broca's area, superior temporal gyrus, insula, and claustrum. In an individual patient with prominent coprolalia, such vocal tics were associated with activity in prerolandic and postrolandic language regions, insula, caudate, thalamus, and cerebellum, while activity in sensorimotor cortex was noted with motor tics. CONCLUSIONS: Aberrant activity in the interrelated sensorimotor, language, executive, and paralimbic circuits identified in this study may account for the initiation and execution of diverse motor and vocal behaviors that characterize tics in TS, as well as for the urges that often accompany them. Arch Gen Psychiatry. 2000;57:741-748

Adult↗

PubMed1997

The audiogenic startle reflex in Tourette's syndrome.

The motor response pattern of the audiogenic startle reflex was studied in 15 Tourette's syndrome (TS) patients and 15 normal, age-matched control subjects, using auditory stimuli at 88 and 114 dB. The louder stimuli readily elicited responses in the orbicularis oculi (in all subjects), masseter, sternomastoid, trapezius, deltoid, and biceps (in most subjects) muscles, with a few subjects having responses in the forearm flexors and quadriceps. The TS subjects did not differ from controls in the onset latency, amplitude, and first peak latency of the reflex response in any of the muscles. Rates of habituation in the orbicularis oculi muscle were widely variable across the subjects, and the two groups did not differ overall in the habituation rates. Our study does not support the reports of an abnormal audiogenic startle reflex in TS.

Acoustic Stimulation↗

PubMed1997

Outcome of neonates with electrographically identified seizures, or at risk of seizures.

A prospective study was conducted to investigate survival at 1 month and survival and developmental outcome at 1 year in a cohort of 53 neonates either suspected of or at risk of having seizures. For all patients, presence of seizures, diagnoses, and structural abnormalities were identified. If seizures were present, seizure variables were quantified. Correlations between neonatal parameters and subsequent outcome were investigated. Forty-three patients survived the first month of life. Background EEG was the only significant predictor of survival at 1 month. Three patients died after 1 month, and 2 of the three had extremely depressed interictal EEGs. Development outcome at 1 year was determined for all available surviving patients. Abnormal findings from brain imaging studies and number of independent electrographic seizure foci were correlated with some aspects of outcome at 1 year. No other correlations were identified between neonatal parameters and outcome.

Child Development↗

PubMed1997

A controlled study of sensory tics in Gilles de 1a Tourette syndrome and obsessive-compulsive disorder using a structured interview.

OBJECTIVE: To determine the prevalence and characteristics of sensory tics in the Gilles de la Tourette syndrome (GTS), and a matched population of patients with obsessive-compulsive disorder (OCD) using a structured assessment. METHODS: 50 subjects each of GTS, OCD, and healthy controls were studied to determine the prevalence and phenomenology of sensory tics, and diagnose tic disorders, OCD, and affective disorders according to DSM-III-R criteria. The severity of tics and obsessive-compulsive symptoms were quantified using the Tourette syndrome global scale (TSGS) and Yale-Brown obsessive-compulsive scale (Y-BOCS) respectively. RESULTS: The GTS group (28%) had significantly-greater life-time prevalence of sensory tics than the OCD (10%) and healthy (8%) groups (P < 0.05). The sensory tics in both the GTS and OCD groups were predominantly located in rostral anatomical sites. Multiple sensory tics occurred in some patients with GTS or OCD, but not in healthy subjects. Within the OCD group, those who had sensory tics had significantly higher TSGS scores (P < 0.0001), and a higher prevalence of GTS (P < 0.005). CONCLUSIONS: Sensory tics seem to be a common and distinctive feature of GTS and that subpopulation of patients with OCD predisposed to tic disorders. Neurophysiologically, a possible explanation for sensory tics is that they represent the subjectively experienced component of neural dysfunction below the threshold for motor and vocal tic production.

Adolescent↗

PubMed1996

Tics status.

OBJECTIVES: To describe two patients with tics status, propose a definition of this syndrome and draw attention to its clinical significance. METHOD: Two patients suffering from Tourette's Syndrome who had developed episodes of continual motor tics that lasted from minutes to hours, were non-suppressible and intruded into normal functioning, were treated with an increase in the dose of haloperidol, in one case with the addition of clonazepam. RESULTS: The offset of the episodes was gradual and the tic disorder was worse after the episodes. One patient had further spontaneous episodes of tics status. CONCLUSIONS: The recognition of tics status has implications for the management as well as our understanding of the pathobiology of tics and Tourette's Syndrome. The definition of tics status should be standardised.

Adolescent↗

PubMed1994

The clinical features of Tourette's disorder: an Australian study using a structured interview schedule.

The clinical features of an Australian series of patients fulfilling DSM-III-R criteria for Tourette's Syndrome (TS) were examined. Fifty patients, recruited from a hospital-based outpatient clinic and a self-help group, were interviewed using a structured schedule. TS is a complex disorder with wide ranging manifestations. Forty male and ten female TS patients with a mean age of 20.8 years (SD 11.2) were assessed. The mean age of onset of tics was 8.3 years (SD 3.3). Simple motor tics occurring in the rostral body regions were more common (eye 86%, face and head 80%) when compared both to simple tics occurring caudally (leg 52%) and complex motor tics (58%). Simple vocal tics were more common (94%) than complex ones (44%). There was a rostrocaudal pattern in the age of onset and severity of simple motor tics. Rates of comorbidity were 32%, 18% and 30% for Attention-Deficit Hyperactivity Disorder, Major Depression and Generalised Anxiety Disorder respectively and this was reflected in the considerable proportion (32%) of the sample who first presented for reasons other than their tics. There were substantial delays between the age of first presentation and diagnosis of TS owing to the insidious onset of the disorder, misdiagnosis and delays in presentation for help. A comparison of the features of the present patients with those of other published studies revealed similarities with some differences. Better clinical recognition of the symptoms and modes of presentation of TS may improve existing delays in diagnosis and treatment.

Adult↗

PubMed1994

Survey on developmental-behavioural training experiences of Australian paediatric advanced trainees.

In order to monitor whether paediatric education has adapted to meet modern practice 91 paediatric advanced trainees were surveyed to elicit their satisfaction with developmental-behavioural (DB) training. A response of 69% was obtained to a postal questionnaire. The traditional imbalance persists, with trainees considering themselves significantly better informed in the medical disciplines (P < 0.001). Satisfaction with training in the 14 developmental disciplines surveyed is less (P < 0.001) and significantly more variable compared with 11 traditional medical disciplines (P < 0.01). Formal rotations in DB disciplines had been received by all respondents by the 7th year of training. However, 46-67% consider themselves ill-informed in learning/school problems, attention-deficit hyperactivity disorder, adolescent problems, paediatric rehabilitation and language impairment. Thirty-seven per cent found formal postgraduate instruction unhelpful. Paediatric advanced training gives exposure to, but unsatisfactory formal education, in developmental and behavioural paediatrics. Current initiatives for mandatory DB training have serious implications for achieving adequate resources and standards to meet clinical and training demands.

Attitude of Health Personnel↗

PubMed1993

A simple collection method for saliva in children: potential for home monitoring of carbamazepine therapy.

We have developed a method of monitoring plasma concentrations of antiepileptic drugs which uses salivary samples, and is suitable for home monitoring in children. To validate the method, paired plasma and saliva samples from 39 children aged between 2 and 15 years were assayed for carbamazepine and its active metabolite, carbamazepine-10,11-epoxide by h.p.l.c. The method uses a gauze-wrapped cotton ball with attached string, to absorb saliva which is then separated using a syringe and plunger. There was no adsorption of CBZ and CBZ-E and they were stable over 1 month in a domestic freezer. Plasma and salivary free CBZ and CBZ-E concentrations were highly correlated (r2 = 0.99 and 0.98, respectively).

Adolescent↗

PubMed1990

Pharmacological characterization of tardive akathisia.

A patient with tardive neuroleptic-induced akathisia was investigated with multiple pharmacological challenges. It was noted that the patient responded positively to benztropine, bromocriptine, and propranolol, and negatively to physostigmine, and showed little or no response to discontinuation of neuroleptics and challenges with metoclopramide, metoprolol, atenolol, and clonidine. The implications of this pharmacological characterization for the understanding of the pathophysiology of tardive akathisia in relation to acute akathisia and tardive dyskinesia are discussed.

Administration, Oral↗