OBJECTIVES: While most neurological models of schizophrenia have focused on cerebral functions, cerebellar abnormality, especially in cerebellar vermis has been repeatedly reported in schizophrenic patients from brain imaging and lesion studies. And cerebellar vermis has been implicated for adaptive control of saccadic eye movements, which has not been studied in schizophrenics to our knowledge. METHOD: We investigated saccadic adaptation using double-step paradigm in 5 patients with a DSM-IV diagnosis of schizophrenia and 5 age and sex-matched normal controls. Gaze and head movements were recorded with scleral search coil method in head-free condition. RESULTS: Time course of adaptation in schizophrenics was similar to that of normal control but it never reached to the complete level of adaptation seen in control, and accordingly gaze gain (gaze amplitude/target amplitude) was low even after 600 adaptive trials. Head contribution to gaze saccade was relatively low and time to peak head velocity was longer in schizophrenics. CONCLUSIONS: Our results suggested that schizophrenic patients used a different strategy of gaze control and some schizophrenics might have cerebellar abnormality. Variability across patients in adaptation parameters need to be further investigated in combination with cerebellar volumetry. This study was supported by "In-san Schizophrenia Research Grant" from the Research Institute of Korean Neuropsychiatric Association in 1997.
Academies and Institutes ; Cerebellum ; Diagnosis ; Diagnostic and Statistical Manual of Mental Disorders ; Eye Movements* ; Head ; Head Movements ; Humans ; Models, Neurological ; Neuroimaging ; Saccades ; Schizophrenia

Nowadays, dental implant is one of the widely used treatment options for edentulous patients. Recently, a method of improving the accuracy of implant surgery using an implant surgical guide has been introduced and widely used in order to accurately place the implant in a proper position. Full-guided and half-guided implant surgery can be distinguished according to the level of surgical guide application during the implant surgery. It is true that full-guided implant surgery exhibits higher accuracy, but half-guided implant surgery is often performed in a clinical situation due to the factors such as the circumstances of the operation. A partially edentulous patient who lost teeth due to tooth fracture and periodontal disease was treated using implant and fixed prosthesis. Half-guided implant surgery was performed using an implant surgical guide during implant surgery, the accuracy of implant placement was analyzed.
Dental Implants ; Humans ; Jaw, Edentulous, Partially ; Methods ; Periodontal Diseases ; Prostheses and Implants ; Tooth ; Tooth Fractures