Focal neurologic signs also known as focal neurological deficits or focal
CNS signs are impairments of
nerve,
spinal cord, or
brain function that affects a specific region of the body, e.g. weakness in the left arm, the right leg,
paresis, or
plegia.[citation needed]
Focal neurological deficits may be caused by a variety of medical conditions such as
head trauma,[1]tumors or
stroke; or by various diseases such as
meningitis or
encephalitis or as a side effect of certain medications such as those used in
anesthesia.[2]
Neurological soft signs, are a group of non-focal neurologic signs.[3]
Frontal lobe signs
Frontal lobe signs usually involve the motor system and may include many special types of deficit, depending on which part of the frontal lobe is affected:[citation needed]
unsteady gait (unsteadiness in walking)
muscular rigidity, resistance to passive movements of the limbs (
hypertonia)
paralysis of a limb (
monoparesis) or a larger area on one side of the body (
hemiparesis)
paralysis head and eye movements
inability to express oneself linguistically, described as an
expressive aphasia (Broca's aphasia)
changes in personality such as disinhibition, inappropriate jocularity, rage without provocation; or loss of initiative and concern, apathy,
akinetic mutism, general retardation
impairment of
proprioception, i.e. postural sensation and sensation of passive movement
sensory and visual
neglect syndromes, i.e. inability to pay attention to things in certain parts of the person's sensory or spatial environment; this may be as extreme as denial of a limb
visual illusions such as micropsia (objects appear smaller) and macropsia (objects appear larger)
visual
hallucinations, displaying elementary forms, such as zig-zags and flashes, in one half of the visual field only for each eye (in contrast, temporal lobe visual hallucinations display complex forms, and fill the entire visual field)
Spinal cord signs generally involve unilateral paralysis with contralateral loss of pain sensation.[citation needed]
Neurological soft signs
Neurological soft signs (NSS) are a group of minor non-focal neurological signs that include
synkinesis.[3] Other soft signs including clumsiness, and loss of fine motor movement are also commonly found in
schizophrenia.[4] NSS likely reflect impairments in sensory integration, motor coordination, and the carrying out of complex motor tasks.[3] When associated with schizophrenia the signs stop if clinical symptoms are effectively treated; and a consensus suggests that they may constitute a state marker for schizophrenia.[3]