Sensory symptoms

TERMINOLOGIES

• Words used to characterize sensory disturbance.

PARESTHESIAS

Typically refers to tingling or pins and needles sensation but may include a wide variety of other abnormal sensation, except pain.

DYSESTHESIAS

It is a more generalized term which denote all types of abnormal sensations including painful ones, regardless of whether a stimulus is evident.

HYPESTHESIA/HYPOESTHESIA

Refers to reduction in cutaneous sensation to a specific type of testing such as pressure, light touch, and warm & cold stimuli.

ANESTHESIA

Refers to complete absence of skin sensation to the same stimuli plus pinprick.

HYPALGESIA OR ANALGESIA

This refers to reduced or absent pain perception (nociception) , such as perception of the pricking quality elicited by a pain.

HYPERESTHESIA

Means pain or increased sensitivity in response to touch.

ALLODYNIA

Describes the situation in which a non painful stimulus once perceived is experienced as painful even excruciating.

Eg: elicitation of a painful stimuli by application of vibrating tuning fork

HYPERALGESIA

Denotes severe pain in response to a mildly noxious stimuli.

HYPERPATHIA

It is a broad term which encompasses all the phenomena described by hyperesthesia, allodynia, & hyperalgesia.

With hyperpathia the threshold for a sensory stimulus s increased and perception is delayed, but once felt , is unduly painful.

Disorders of deep sensation arising from muscle spindles, tendons,& joints, affect propriocepton.

•Manifestation include (particularly when eyes closed or in dark)Imbalanceclumsiness of precision movement sensoryUnsteadiness of gait. ataxia

other findings on examination usually include reduced or absent joint position & vibratory sensibility and absent deep tendon reflex in the affected limbs.

Romber’s sign is positive - which means the patient sways markedly of topples when asked to stand with feet close together and eyes closed.

In severe state of deafferentiation involving deep sensation, the patient cannot walk or stand or even sit unsupported.

PSEUDOATHETOSIS

Is continuous involuntary movements of the outstretched hands and fingers occur, particularly with eyes closed.

SENSORY SYMPTOMS

NEGATIVE SYMPTOMS POSITIVE SYMPTOMS

POSITIVE SYMPTOMS….

• The prototypical positive symptom is tingling, that is pins and needle sensation.

• Other positive symptoms include altered sensations that are described as

Pricking

Band like

Lightening like shooting feeling (lancinations)

aching

.Cont…

Knifelike

Twisting

Drawing

Pulling

Tightening

Burning

Searing

Electrical

Or raw feelings

.Positive symptoms usually results from impulses

generated at sites of lowered threshold or heightened excitability, along a peripheral or central sensory pathway.

The nature and severity of the abnormal sensation depend on the-NumberRateTimingDistribution of ectopic impulses, andType and function of the nervous tissue from which

they arise.

.Since positive symptoms represents excessive

activity of sensory pathways- they are not represented as sensory loss on examination

Negative symptoms…..

• Negative symptoms represents loss of sensory functions and are characterized by diminished or absent feeling.

• It is often experienced as numbness.

• It is estimated that at least half half the afferent axons innervating a given site are lost or functionless before a sensory deficit can be demonstrated by clinical examination.

The threshold of sensory symptoms varies with how rapidly function is lost in sensory nerve fibre.

If the rate of loss is low-lack of cutaneousfeelings may be unnoticed by the patient -and difficult to demonstrate on examination, even though few sensory fibers are functioning.

If rate of loss is rapid- both positive and negative phenomenon are easily identified.

Thank u……