An Apparatus for the Measurement
of a Neonate's General Activity
ADAM P. MATHENY, JR., PHD,* and KENNETH HULL, MSf
A simple, inexpensive device for sensing a neonate's gross activity is described.
Ordinary VU meters, inserted in a foam rubber crib mattress, transduce neonatal
movement to an output voltage capable of being recorded. No external power
source is needed. Ratings of visually observed movement were correlated with
ratings of recorded signals obtained from 4 neonates. A correlation coefficient of
+.77 was found between these ratings. The use of this device suffers little from
the problems of (1) balancing a stabilimeter platform, and (2) dampening
oscillations after movement.
VJONTROLLED STUDIES of the overt forms
of neonatal behavior have relied greatly
upon observations of changes in general
or gross activity.
selected gross activity as a neonate re-
sponse variable because it is easy to
elicit and observe under conditions of
defined stimulation. Moreover, the de-
tection and measurement of activity can
be (and has been) simplified by the de-
velopment of movement-sensing devices
From The Johns Hopkins Medical School,
Department of Pediatrics, Baltimore, Md.
in part by Research Grant
MHO7622-02 from the National Institute of
Mental Health, US Public Health Service.
The authors wish to express their apprecia-
tion for the help of G. Webb, Assistant Pro-
fessor of Biomedical Engineering, Johns Hop-
kins Medical School, and L. Pryzborowski.
Received for publication Jan 6, 1969; revision
received April 2, 1969.
'Present address: Department of Pediatrics,
University of Louisville School of Medicine,
fPresent address: School of Medicine, Uni-
versity of Maryland, Baltimore, Md.
—thereby producing experimental ease
The activity sensing devices are usu-
ally designed on the principle of a basic
stable platform (stabilimeter), coupled
mechanically or electrically to a record-
ing unit. Refinement of such platforms