Medicina Clínica 1950 (pdf) - Museo Archivo Histórico | SEN ...

sion at the knee and hip if these should happen to
occur. BRAIN and CuRRAN found that this reflex was
elicitable in all children aged nine months or less,
and in almost all aged under a year, while it had
disappeared in all but one child over the age of two
years. The foot grasp reflex was found to be absent
in two infants aged six months who both suffered
from bilateral pyramidal lesions and exhibited marked
spasticity. They pointed out that the presence
of grasp reflex of the foot thus corresponded roughly
with the normal persistence of the extensor plantar
reflex in infancy.
BR¡,ru and Cunn,c.n observed that the foot grasp
reflex was fairly common in Mongolian imbeciles.
They investigated the reflex in fifty-nine such pa'
li,
tients, ranging from one to forty-five years of age.
They found it present in both feet in twenty-three
and in one foot only in five. It was absent in twenty
and the result was doubtful, mainly owing to the
difficulty of examination, in eleven. Thus. the reflex
was obtainable in one or both feet in approximately
half the cases. It was rarely observed in Mongolian
imbeciles after the age of twenty' Up to that age it
was present in twenty-five out of forty-two patients;
aftef that age in only three out of seventeen'
Bn¡.I¡r aná Cunn¡rv also reported four additional
cases of organic lesions of the nervous system lea'
ding to grásp reflex of the foot. The first was a
natÉnt wlth co.teenital choreo-athetosis of bilateral
hirtribrrtioo. Thi! patient, a child aged two and a
half years, showed no grasp reflex o-f- the
.hands,
but a vigorous grasp reflex was readily elicitable
in both feet. The slightest contact with the flexor
surface of the toes, ór the disal half of the sole,
evoked strong flexion of all the toes, which were
maintained ii tonic flexion for a quarter to half a
minute or longer. The second patient h-ad un unve-
,ifi.d ,u*o.rt "of th" corpus callosum. She exhibited
bilateral weakness with some spasticity and extensor
nlantar responses associated with'un extremely li'
e.a'sp ,"flex of both hands and both feet'
iil" ,ftitá patient had a subdural haematoma on the
"orou,
ti* ";¿" *hi"h ptobably been present for at least
ii?"" *"ttlls. Hl also showed bilateral signs of a
ly."*i¿"f lesion and in addition the grasp reflex
Mnnrcr¡u Cr,Íxrcl
Touo XV
1950 - Núm. 5
was readily elicitable from both hands and both
{eet, being more virogous in both insteances on the
right side. The fourth patient had a meningioma
of the falx which was embedded in the medial aspect
of the left frontal lobe reaching pack to within
about 2 cm. of the precentral gyrus. This patient
had a right hemiparesis and hemi-apraxia with marked
verbal dysphasia. A strong grasp reflex was
present in the right hand and also in the right foot.
Gorrlsretl ( I93B) contributed a further study of the
grasp reflex of the foot which he termed . He related
it to a lesion of the opposite frontal lobe and explained
it as a response of the lower mechanisms
in the higher centres of the damage. He emphasised
its value as an early sigu of the frontal lobe lesion
and pointed out that when it appears on the ipsilateral
side it indicates an extension of the pressure
to the hemisphere on the side opposite to the
lesion.
Pnysror.ocrclr- Aspncrs. - The physiology of the grasp
reflex has been studied by Rrcrirn anJ'Hrwrs (1932)
and by Fur-ror,r and his collaborarors (1932, 1936, l93B)
and this aspect of the subject has recently been well
s-ummarised by FulroN (1943). Animal expeiiments have
shown that the grasp reflex is produced in monkeys and
chimpanzees by isolated removál of the promotor area.
It is present in animals in which the motoi and premotor
areas have been removed bilaterally, and its "ir..u"t".istics
are found also in animali which have been
rendered completely thalamic through removal of both
hemisph-eres. lt appears to be dependent upon lhe integrity
of the tegmentum since ii is not irecessary for
the striatum and anterior port of the thalamus io be
present in order that the response may be elicitable.
Fulror describes ir as a flexoi response of the digits
postural in character and it is affected by change of
the position of the body in space, togethei ¡uith lther
,postural reactions. Thus, it ii a reléase phenomenon
which is the result of the d'estruction of i.*" n¡.".
originating in the premotor cortex which normally inhibir
it.
Ruce¡'tr cLrNrcAL oBSERvATroNs.-An excellent
review of the whole subject has recently been published
by MnssroN-VBRNroRy (1948) and new -observations
have been made by Ssyrranrn and Dr¡v.
Ny-BRowN (1948). These authors distinguish the
glasp reflex from the instinctive grasp reaction.
They define the grasp reflex as na siereótyped prehensile
reaction of the flexors and the adductori of
the fingers and the flexor muscles of the flexors and
the adductors of the fingers and the flexor muscles
of the wrist which can be elicited in fractional
parts by appropriate localisation of the stimulus.>
The adequate stimulus for the full reaction is dual.
The first essential is a distally moving deep pressure
over a specific area of the palmar surface of
joints in the hand which elicit a rapid, brief muscular
contraction ( phase), which de.
velops into a strong phase only i{ traction
is made upon the tendons of the flexor and
adductor muscles thus thrown into preliminary con-,
traction. Response is then maintained only by traction,
The instinctive grasp reaction, according to