considered as of great negative or positive value: often the diagnosis
is only made by exclusion. The Cheyne-Stokes respiration, pupillary
variations, differences in pulse-rate and volume, are present in such
varied conditions, irrespective of the nature of the lesion, as to
render them of minor value in differential diagnosis.
DOUBLE CONSIOUSNESS is a rare condition, in which the subject appears
to have separate forms or phases of consciousness, one normal, the
other morbid. This occurs in hypnotic and somnambulic states, probably
also in certain cases of insanity and epilepsy. The current of normal
consciousness is suddenly broken; the patient enters into the second
or abnormal state, in which he acts, writes, speaks, moves about with
seeming consciousness; but after a variable time a return to normal
consciousness reveals a break in the continuity of the memory: the
patient has no recollection whatever of what he did or said in the
morbid period. In the hypnotic state subjects may show increased power
of perception, and are strangely susceptible to suggestions or
guidance by the experimenter. In a second attack the patient often
refers back to the first, and does things in continuation or
repetition of what he previously did, apparently taking up the same
line of thought and action. The morbid states, long or short, are
joined together by memory, but are wholly unknown in the normally
conscious states. In other words, the patient leads two (or three,
according to a few observations) separate lives, each one forming a
chain of interrupted conscious states. In epilepsy we observe
remarkable breaks in normal consciousness: the patient goes through
certain acts or walks a distance or commits a crime in a dream-like
state, and suddenly, after the lapse of a few minutes, hours, or days,
becomes normally conscious and has no recollection of what he did with
such apparent system and purpose during the seizure. It might,
perhaps, be as well to classify these phenomena under the head of
amnesia. A case is on record where a man travelled, seeming normal to
fellow-travellers, from Paris to India, and who was immensely
astonished on coming to himself (return to common consciousness) in
Calcutta. Many murders have been committed with apparent design and
with skill by epileptics, who upon awaking from their dream-like state
were inexpressibly horrified to hear of their misdeeds.
AMNESIA, or loss of memory, may vary in degree from the occasional
failure to remember which is allowed as normal, to the absolute
extinction of all mental impressions or pictures. This word and the
expression memory are here used in a restricted sense, reference being
had only to purely intellectual and sensorial acts related to
intellection. If we take the general or biological sense of the term
memory as meaning the retention of all kinds of residua from
centripetal impressions and of motor {29} centrifugal impulses,
including common sensory and visual impressions, special sense
impressions, all unconsciously received impressions, emotional,
intellectual, and motor residua, we should consider amnesia in a
correspondingly general way. This, however proper for a physiological
study, would be far too complex and premature for an introduction to
practical medicine. Recognizing memory, therefore, as a universal
organic attribute—a capacity to retain impressions—we will treat of it
only in the commonly-accepted sense referred to supra.
Failure of memory may be real or apparent. In the latter sense amnesia
is induced by diversion of the attention into a channel different from
that in which the line of inquiry is conducted. A normal example of
this is seen in the state known as preoccupation, where a person
intent upon a certain thought or action forgets who is about him,
where he is, and if asked questions fails to answer or answers
incorrectly. In pathological states, as in acute curable insanity,
apparent loss of memory is often caused by the domination of an
emotion or of delusions. In both cases, if the subject can be roused
or brought to himself, he remembers all that we inquire about and is
amused at his previous false answers or silence. Real amnesia consists
in the actual blotting out of recollections or residua in a partial or
general manner, for a time or permanently. These differences serve as
the basis of a complicated subdivision of amnesia which it is not
necessary to fully reproduce here.
Temporary partial amnesia is a variety which is frequently observed in
normal persons, even the most gifted. A word or fact escapes us, seems
wholly lost for a few minutes, hours, or days; the more we strive to
recall it, the less we succeed; yet later, when not sought for, the
fact or word appears in our consciousness as if spontaneously, but
more probably by some effect of the law of association. Such partial
and momentary forgetfulness may assume proportions which render it
pathological. What is known as transitory aphasia may be classed in
this group. In a few minutes or hours a person without apoplectic,
epileptic, or paralytic phenomena loses all power to express his
thoughts by speaking or writing; there is verbal amnesia and agraphia.
The subject is conscious of his condition and of the wholly futile or
incorrect attempts he makes to communicate with others.
Temporary complete amnesia is almost equivalent to loss of
consciousness, yet not strictly so. For example, after a sharp blow
upon the head a person may perform complicated acts, reply to
questions, and apparently act normally, yet after a variable time he
will declare that he remembers absolutely nothing of the injury and
what he did or said for hours or days afterward. The same phenomenon
is observed in the course of psychoses, neuroses (epilepsy), in some
acute diseases, and in certain states of intoxication.
Permanent partial amnesia occurs in states of dementia, such as senile
dementia, paralytic dementia, and in certain cases of aphasia. Great
gaps exist in the patient's memory; some things are well recalled,
others wholly and for ever effaced. The psychological law governing
the failure of memory in these cases is that the earliest and
strongest impressions survive, while recent and less forcible (_i.e._
less interesting) ones are lost. Substantives or names are especially
liable to obliteration, as are also many of the delicate residua which
lie at the basis of the subject's ethical conceptions and acts.
{30} Permanent complete amnesia is observed at the end of degenerative
cerebral diseases, as organic dementia, whether of the form termed
secondary or that designated as paralytic. Sometimes after acute
general diseases the memory may be a perfect blank for a considerable
length of time, and education has to be repeated. Memory may be so
completely absent that cases are known in which the patient gave a
fresh greeting to the asylum physician every two or three minutes
indefinitely, as if each were a first meeting. Momentary perception
and automatic (reflex) response are there, but no impression is made;
there is no residuum left in the cortical centres. In these cases
amnesia is accompanied by degeneration of the visual, auditory, etc.
cortical areas or centres.
An interesting form of amnesia, not generally recognized as such, is
the loss of acquired skill in muscular movements, such as are
necessary for writing, for using tools, and for doing various delicate
professional movements. Here the motor residua acquired by laborious
education or training are gradually lost without actual paralysis or
ataxia. This variety is exquisitely illustrated by certain cases of
dementia paralytica where long before marked intellectual symptoms
occur there is loss of skill in mechanical arts and in handwriting.
In testing a subject's memory due attention should be paid to the law
of the survival of older and more interesting residua, as well as to
the power of the law of association. Such questions should be asked as
pertain to recent events in the patient's experience, and about
matters which are not closely related logically. A patient who might
tell us nearly all about his early personal experiences, his business
and family relations, incidents of his childhood, etc., would fail to
remember what he had for breakfast, what he did the day before, etc.
The physiological cause of real amnesia is impairment in the vitality
(nutrition) of ganglion-cells in the various cerebral sensory areas or
centres, and of the motor area as well (motor residua). In cases of
transitory amnesia we suppose this to be due to the action of toxic
agents, to anæmia, and impaired molecular or chemical nutrition, as
after acute diseases, in extreme debility, in psychoses, etc. In cases
of terminal permanent dementia, autopsies afford us evidence of
degeneration and disappearance of ganglion-cells: we find granular and
fatty pigmentation, atrophy, calcarous degeneration of these bodies,
thickening and shrinkage of the neuroglia, and degenerative changes in
blood-vessels. Doubtless degeneration or destruction of association
fasciculi of nerve-fibres in the cortex cerebri or in the white
substance plays a considerable part in the production of permanent
amnesia, but we are as yet unable to give a clear demonstration of
this. Theoretically, we may admit an organic loss of memory with the
following conditions of the brain: (1) diseased perceptive (sensory)
centres or motor area with normal association fasciculi; (2) normal
perceptive centres and motor area with degenerate or broken
association fasciculi, connecting these parts with one another and
with the more strictly ideational or expressive (centrifugal) areas
and parts of the brain and spinal cord.
Amnesia—or, more properly speaking, dulness of perception and
feebleness of retention of residua—occurs as a strictly congenital
condition from imperfect cerebral development, or a little later in
life from infantile diseases, constituting one of the aspects of
idiocy.
{31} WORD-DEAFNESS is a special morbid psycho-sensory state in which
the sounds of language lose their significance for the patient. The
sense of hearing is preserved for common sounds, and even music in
certain cases; words are heard, but not understood. A patient of mine
having this symptom used to say, “If I go to a lecture or hear a
sermon, I hear the speaker, but what he says is all Greek to me.” On
the other hand, this gentleman could go to a concert and understand
the musical notes. This condition occurs as a part of the
symptom-group aphasia, or it may show itself independently in the
course of limited cerebral cortical degenerations. The lesion causing
word-deafness is usually found in the left hemisphere, in the first
and second temporal gyri, or it may be in the inferior parietal lobule
and gyrus supra-marginalis, penetrating deeply enough to injure
fasciculi going into the temporal lobe. It would appear, from the
evidence now before us, that the centre for psychic hearing is in the
caudo-dorsal part of the temporal lobe.
WORD-BLINDNESS, or alexia, is another special morbid psycho-sensory
state, in which the visible signs of language lose their significance
for the patient. Usually there is no impairment of sight; the patient
can see the letters and words as objects, but he cannot read them at
all, or must do so letter by letter. Even numerals and pictures of
objects in some cases become unintelligible. In testing for this
condition a possible confusion with verbal amnesia must not be
forgotten. In such a case the patient knows the word or object, but
cannot name it; usually he can, however, inform us by signs or
indirect expressions that he takes proper cognizance of the object.
Alexia is present in a certain proportion of cases of aphasia, and it
may be complicated with lateral hemianopia. The exact seat of the
lesion producing alexia is at present unknown. Theoretically, however,
we must place it in the course of paths from the cortical visual area
(cuneus and adjacent gyri) to the general speech-centre. Psychic
blindness for objects in general (soul-blindness of the Germans) is
now quite conclusively proved to be due to degeneration of both
occipital lobes, more especially their mesal gyri, where the visual
centres are. This psycho-sensory state, with the accompanying cortical
changes, has been demonstrated in cases of dementia paralytica.
APHASIA, or loss of the faculty of language, is so important a symptom
as to deserve elaborate consideration in a separate article of this
volume; and to it the reader is referred. Suffice it here to state
that aphasia may be classified into three forms: (1) Sensory aphasia,
in which there is primary disorder of the psycho-sensory (perceptive
or centripetal) part of the complex central mechanism for speech; (2)
Motor aphasia (including ataxic aphasia), in which the primary lesion
affects the motor (expressive or centrifugal) parts of the mechanism;
(3) Amnesic aphasia, in which loss of memory (effacement of residua)
of words and signs is the prime condition.
II. Sensory Symptoms.
HYPERÆSTHESIA is a condition of exalted excitability in the various
parts of the sensory apparatus: terminal nervous organs, nerve-trunks,
central gray matter. We may admit such a state as existing {32}
independently of consciousness, as where a lesion cuts off
communication between the perceptive cerebral centres and the
periphery, but in practice we consider only conscious hyperæsthesia.
In this state the subject may be able to perceive (feel) slighter
impacts than would affect a normal individual, or he receives an
exaggerated, usually unpleasant, impression from ordinary excitations.
It may also be said that hyperæsthesia exists as a purely subjective
state, psycho-sensory hyperæsthesia, without external mechanical
excitations.
(_a_) Hyperæsthesia of common tactile sensibility in the skin and
mucous membranes is frequent. The least touch is felt with unpleasant
acuteness and causes unusual reactions of a reflex order; frequently,
but not necessarily always, a sensation of pain is produced at the
same time. It has been claimed that in certain cases the points of the
æsthesiometer could be perceived (distinguished as two points) at
smaller distances than the average normal, but I have never been able
to demonstrate this to my satisfaction. The simplest form of tactile
hyperæsthesia is met with in persons of a highly nervous organization,
in those under the influence of strong emotions, in the hypnotic
state, and while intoxicated. The common pathological conditions in
which increased sensibility is found are meningitis (cerebral and
spinal), hydrophobia, tetanus, neuritis, dermatitis, hysteria, and
spinal irritation; also in connection with inflammations and
traumatisms.
(_b_) Hyperalgesia, often coinciding with (_a_), is that condition in
which pain is produced by excitations so slight that they would not
affect a healthy nervous apparatus: it is commonly designated as
tenderness. Acute and dull, superficial and deep tenderness should be
sought for and distinguished, as having different values in diagnosis.
A type of deep tenderness is that found upon pressing steadily upon a
diseased nerve-trunk. Acute superficial hyperalgesia is best studied
in cases of trigeminal neuralgia and spinal irritation. Occasionally,
universal hyperalgesia is met with, usually in hysterical women.
(_c_) Hyperæsthesia to thermal impressions is ordinarily shown with
reference to cold. In cases of neuralgia or neuritis cold is felt
excessively and painfully; in some cases of posterior spinal sclerosis
there is the greatest dread of draughts of cold air, and patients
protect their legs in an extraordinary manner.
(_d_) Hyperæsthesia of the muscular sense.[3] The special sensations
or notions of muscular states and activities which we possess may be
considerably exalted, as shown by greater delicacy and rapidity of
movements, and by the abnormally acute way in which perceptions of
form and dimensions are obtained by the subject without assistance
from other senses. Examples of this condition are met with in hysteria
and hypnotism.
[Footnote 3: This term is employed as clinically sufficient. It is
impossible in this article to enter into a consideration of the
various theories held with reference to the function in question,
whether it be psycho-motor, psycho-sensory, or a true muscular
sensibility. It certainly differs much from the various forms of
common sensibility, and has special paths.]
(_e_) Visceral hyperæsthesia is chiefly shown by abnormal
consciousness of the presence and action of an organ. Visceral pain
usually accompanies this, and is the more prominent symptom.
(_f_) Increased reflex actions (emotional, motor, vaso-motor, and {33}
secretory) rarely fail to accompany hyperæsthesia in its various
forms. In the hypnotic exaltation of muscular sense remarkable psychic
effects may be induced, partly in a reflex way, but perhaps chiefly
through the law of association.
PARÆSTHESIÆ are sensations which arise centrally in nerve-fibres or
nervous centres, and are projected outward and referred to the
periphery or surface by consciousness, in obedience to the general law
of outward projection of sensations in the Ego. They may be produced
by external agencies or arise centrally without demonstrable cause.
Their number and variety are very great, varying somewhat with the
descriptive powers and self-consciousness of the patient, the chief
being pain, formication, numbness, coldness and heat, constriction and
distension, malposition, imaginary movements, etc. etc.
(_a_) Pain, the most distinct and frequent of paræsthesiæ, is by most
authors classed as a hyperæsthesia, yet a careful analysis will show
the difference. Pain and hyperæsthesia often coexist and are
inseparable, yet in a large proportion of cases of nervous diseases
the former sensation occurs independently, sometimes in regions where
absolute anæsthesia exists (anæsthesia dolorosa), and even apparently
in lost parts (neuralgia after amputations). We are consequently
justified in considering most pains as paræsthesiæ. Pain assumes many
forms, some real and typical, others as various as the lively
imagination of nervous patients can make them. Thus we have sharp,
cutting, darting pains in neuralgia, posterior spinal sclerosis, etc.;
aching, throbbing, pounding pains in cephalalgia, inflammatory and
traumatic conditions; boring, crushing, distending, constricting,
burning pains, etc. etc. In some cases the sensation is only
semi-painful, and more akin to paræsthesia (neuritis, parenchymatous
lesions).
(_b_) Numbness, prickling, and formication usually coincide. They may
easily be produced experimentally by pressure upon a nerve-trunk or by
the exhibition of aconitia, so that any one may study these sensations
for himself. By taking one-fiftieth of a grain of Duquesnel's
crystallized aconitia the experimenter will soon find himself the
possessor of intense subjective sensations of prickling, numbness,
vibrations, and cold, lasting several hours. He will be able to
satisfy himself that though the finger-tips feel numb, as if there was
a coating or layer of something interposed between the skin and
objects, he can distinguish tactile perceptions very well. In the more
serious experiment of compression of a nerve-trunk a most interesting
succession of phenomena will be observed: the first effects of
pressure are various paræsthesiæ in the parts supplied by the nerve;
then these sensations (prickling, numbness, swelling, vibration, heat,
and cold) cease; paralysis and anæsthesia occur. If the compression be
now interrupted, after a few moments the paræsthesiæ reappear, more
intensely, as a rule, and as they gradually fade a normal state of
sensibility is re-established. By making such experiments it is easy
to convince one's self that anæsthesia and numbness are different
conditions: indeed, during the stage of recovery from nerve-pressure
distinct hyperæsthesia may be demonstrated. These results throw much
light on the origin and diagnostic value of paræsthesiæ as expressions
of irritation, central or neural, of nervous elements. At the same
time, in practice, we occasionally meet with slight dulness of tactile
sensibility in numb {34} parts. Another point to be remembered is that
while patients usually complain loudly of paræsthesiæ, they are
sometimes wholly unaware of anæsthesia (hysterical analgesia, for
example); therefore sensibility should be tested even if the patient
does not mention sensory disturbances.
Numbness, formication, etc. occur in a vast number of nervous
affections—in cerebral and spinal organic lesions, in neuritis, in
toxic conditions, and in neuroses. The distribution of paræsthesiæ is
a valuable index to the seat of the lesion.
(_c_) Cutaneous itching and prickling may occur independently of any
other skin lesion, constituting true or nervous prurigo. This may be
universal and last for years.
(_d_) Paræsthesiæ of pressure are felt either as expansive or
constrictive. The part appears swollen to consciousness, or it seems
to be tightly compressed. Both these sensations are often felt about
the head in a variety of pathological states, and an absurd and
dangerous fashion has arisen of looking upon a sense of fulness in the
head as indicative of hyperæmia. The sense of constriction may show
itself around one toe, a leg, the trunk, around the neck, etc.; it may
be narrow, like a cord, or broad and extensive, like a stocking or
corset. Sometimes it is localized, and likened to the grasp of a hand
or a spot-pressure. Not infrequently, especially in cases of
paraplegia, the sensation of pressure is combined with subjective
cold, the legs feeling as if tightly encased in ice.
(_e_) Subjective sensations of heat and cold are often of the
strongest kind, and are very distressing. A part whose real objective
temperature is normal may appear to the patient's consciousness as icy
cold or burning hot, even to the degree of apparent contact of fire
(causalgia of Mitchell). We observe such sensations in posterior
spinal sclerosis, myelitis, neuritis, injuries to nerves. In some
functional cases complaint is made of patches of hot or cold skin, not
relieved by cold or heat.
(_f_) Odd sensations, such as rolling or longitudinal motion of
something under the skin, general or local throbbing, coition
movements, are described, especially in functional or hysteroid cases.
(_g_) Sensations of hunger, thirst, dyspnœa, defecation, micturition,
the sexual feeling, may all appear in an abnormal or unprovoked
manner, and are to be classed as visceral paræsthesiæ. An important
paræsthesia of this variety is met with in cases of hypochondriasis
and melancholia; it is a sense of indescribable distress, with
constriction, usually at the epigastrium and about the heart—the
precordialangst of the Germans, or, as we would term it, præcordial
anguish.
(_h_) Paræsthesiæ of the muscular sense occur. The subject has a
feeling as if a part were lying in an unnatural position, or as if it
were being pulled or twisted in various ways, and he is sometimes
obliged to assure himself by the use of sight and by tactile
examination that the sensation is illusory.
(_i_) Hallucinatory paræsthesiæ are those which are so well defined
and strong as to need the aid of other senses and reasoning to
convince the patient of their unreality. A peculiar example of this is
what occurs after amputation of a limb: for days or weeks the lost
member is felt with the utmost distinctness; the absent fingers or
toes may be moved in imagination and their position described.