TY  - JOUR
PY  - 1995//
TI  - EMG-responses to sudden onset free fall
JO  - Acta oto-laryngologica. Supplementum
A1  - Bisdorff, A. R.
A1  - Bronstein, A. M.
A1  - Gresty, Michael Andrew
A1  - Wolsley, C. J.
A1  - Davies, A.
A1  - Young, A.
SP  - 347
EP  - 349
VL  - 520
IS  - Pt 2
N2  - Recordings of axial and limb muscles in reaction to a free fall induced startle were performed in subjects while they were lying on a tilting couch with their eyes closed. Young normals (n = 24, aged 31.1 +/- 6.6 years) showed an activation sequence consisting of sternomastoid (N.XI: 57 ms), abdominal muscles (T10: 65 ms), quadriceps (L3: 75 ms) and deltoid (C5: 78 ms) and tibialis anterior (L4: 80 ms). The sequence of activation is not compatible with the current hypothesis of the startle being produced by a single volley spreading rostrally and caudally from the lower brainstem. Instead it is suggested that the startle is a patterned response organized by a putative reticular generator capable of spatio-temporal sequencing. Two avestibular patients had responses at mildly delayed latencies, showing that these can be elicited by non-vestibular inputs. Similar testing of 11 subjects aged 70-80 years showed a latency delay of ca. 26% in the EMG response but a similar activation sequence. The amount of delay in the elderly can only partially be attributed to age-dependent motor conduction slowing and suggests a prolongation of central processing time. In patients with advanced stages of akinetic-rigid syndromes abnormalities were seen in cases with an involvement of the brainstem reticular formation.<p /> <p>Language: en</p>
LA  - en
SN  - 0365-5237
UR  - http://dx.doi.org/
ID  - ref1
ER  -