Defective imitation of finger configurations in patients with damage in the right or left hemispheres: An integration disorder of visual and somatosensory information?
To explore the mechanism underlying the imitation of finger gestures, we devised a simple imitation task in which the patients were instructed to replicate finger configurations in two conditions: one in which they could see their hand (visual feedback: VF) and one in which they could not see their hand (non-visual feedback: NVF). Patients with left brain damage (LBD) or right brain damage (RBD), respectively, were categorized into two groups based on their scores on the imitation task in the NVF condition: the impaired imitation groups (I-LBD and I-RBD) who failed two or more of the five patterns and the control groups (C-LBD and C-RBD) who made one or no errors. We also measured the movement-production times for imitation. The I-RBD group performed significantly worse than the C-RBD group even in the VF condition. In contrast, the I-LBD group was selectively impaired in the NVF condition. The I-LBD group performed the imitations at a significantly slower rate than the C-LBD group in both the VF and NVF conditions. These results suggest that impaired imitation in patients with LBD is partly due to an abnormal integration of visual and somatosensory information based on the task specificity of the NVF condition.
Department of Rehabilitation, Atago Hospital, 1-1-13, Atagomachi, Kochi 780-0051, Japan; Department of Physiology, Kochi Medical School, Kochi University, Oko-cho, Nankoku, Kochi 783-8505, Japan. Electronic address: okita-pt@jn3.so-net.ne.jp.
Manabu
M
Okita
Department of Rehabilitation, Ichinose Hospital, 1-5-11, Kokutaijimachi, Nakaku, Hiroshima 730-0042, Japan. Electronic address: yukihiro_t2_h@yahoo.co.jp.
Takashi
T
Yukihiro
Department of Physical Therapy, Tosa Rehabilitation College, Otsu, Ohtsu, Kochi 781-5103, Japan. Electronic address: ptrc.k-miyamoto@tosareha.ac.jp.
Kenzo
K
Miyamoto
Department of Physical Therapy, Faculty of Health Science, Kio University, Umaminaka, Koryo, Kitakatsuragigun, Nara 635-0832, Japan. Electronic address: s.morioka@kio.ac.jp.
Shu
S
Morioka
Department of Physiology, Kochi Medical School, Kochi University, Oko-cho, Nankoku, Kochi 783-8505, Japan. Electronic address: kabah@kochi-u.ac.jp.
Hideto
H
Kaba
D000368:Aged; D000369:Aged, 80 and over; D001930:Brain Injuries / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology; D005260:Female; D005385:Fingers / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D005868:Gestures; D006801:Humans; D007100:Imitative Behavior / Q000502:physiology*; D008297:Male