Neurological Glossary

DAFO

Dynamic Ankle Foot Orthosis

Dawson's fingers

Ovoid demyelinating lesions with their long axis perpendicular to the ventricular surface seen in multiple sclerosis

Death by neurological criteria

Irreversible loss of all brain function

Decerebrate rigidity

Stereotyped posture consisting of extension of all four limbs occurring with transaction between the superior collicui and inferior collicli in the midbrain; often used synonymously with extensor posturing

Decorticate rigidity

Stereotyped posture consisting of flexion of the forelimbs and extension of the hind limbs occurring with transaction between the diencephalon and midbrain; often used synonymously with flexor posturing

Decussate

To cross

Deja vu

Feeling as if one has lived through or experienced this moment before; may occur in people without any medical problems or as a seizure aura

Delayed sleep phase syndrome

Circadian rhythm disorder in which in the daily sleep/wake cycle is delayed with respect to clock time such that sleep occurs well after the conventional bedtime; common in young adults

Delirium

Abnormal mental state characterized by disorientation

Dementia

Acquired and sustained loss of memory and other intellectual functions that is of sufficient severity to interfere with daily functioning

Dementia pugilistica

Chronic traumatic encephalopathy caused by cumulative and repetitive head trauma and manifesting as dementia and parkinsonism

Demyelination

Destruction or loss of the myelin sheath surrounding axons; results in impaired nerve impulse conduction

Dendrite

Receiving portion of the neuron

Dermatome

Distribution of sensory innervation on the skin of the body and the limbs

Diabetes

See: Insulin. A condition in which the body cannot use glucose (sugar)

Diaphragma sellae

Thin dural membrane overlying the sella turcica that is fenestrated to allow passage of the infundibulum

Diaphysis

The part of a long bone formed from the primary centre of ossification

Diaschisis

Depression of metabolism at sites distant from

Diastematomyelia

Longitudinal division of the spinal cord by a septum of bone

Diencephalon

Thalamus

Diffuse axonal injury

Widespread damage to white matter due to rotational shearing forces with head trauma

Diffuse Lewy body disease (Lewy body dementia)

Form of dementia associated with fluctuating alertness

Diplegia

Where both legs are affected but the arms are not [or only slightly so]

Diplopia

Double vision

Disability

A substantial and long-term physical or mental impairment that reduces functions such as mobility

Dislocated

A joint shifted out of position

Dissociated sensory deficit

Impairment of pain/temperature sensation with preservation of vibration/proprioception or vice versa; implies lesion of brainstem or spinal cord involving one sensory tract but sparing the other

Distal

Further from the axial skeleton.

Distractibility

The inability to concentrate

Doman Delacato Therapy

Form of therapy used in the treatment of brain injury

Doppler scan

An ultrasound technique using soundwaves to obtain a graphic display of blood flow

Dorsal

Posterior

Dorsal columns

Ascending axonal tract running in the dorsal funiculus of the spinal cord that carries tactile and proprioceptive information to the brain; fibres cross in the ventromedial medulla to become the medial lemniscus

Dorsal motor nucleus of the vagus

Parasympathetic nucleus that stimulates secretion from glands of the pharynx and thoracic and abdominal viscera

Dorsal rhizotomy

Surgical procedure involving sectioning of the dorsal spinal nerve roots performed to reduce spasticity

Dorsal root ganglion

Collection of cell bodies located in the intervertebral foramina that transduce sensory information into neural signals and transmit these signals to the CNS

Dose failure

Phenomenon in which an individual dose of medication has no effect; occurs in Parkinson disease possibly in association with a tablet getting stuck in the throat or delayed gastric emptying

Double Hemiplegia

Paresis involving the limbs on both sides of the body with the upper limbs more severely affected than the lower.

Double simultaneous stimulation (DSS)

Ability to detect two stimuli applied simultaneously to opposite sides of the body; for tactile DSS

Drop foot

A gait problem

Drop metastases

Tumour masses in the lumbosacral spinal cord due to CSF spread of neoplastic cells .

Duction

Movement of one eye

Dura mater

Outermost layer of the meninges covering the brain and spinal cord; consists of a thick fibrous tissue that is adherent to the inner table of the skull and forms a protective sheath in the vertebral canal

Dural tail sign

Tail of dural enhancement seen on CT or MRI in association with meningeal neoplasms such as meningioma

Duret haemorrhages

Secondary haemorrhages occurring in the diencephalon

Dysarthia

Imperfect production of the sounds used in speech

Dysdiadochokinesia

Impaired ability to perform rapid alternating movements .

Dysesthesia

Pain or discomfort in response to a stimulus .

Dysgeusia

Distorted taste perception

Dysgraphia

Difficulty in writing due to a defect of brain function other than sensory defect (the alternative word 'agraphia' is sometimes used)

Dyskinesia

Abnormality of movement/bizarre spontaneous movements

Dyslalia

Difficulty in speaking due to a defect of brain function other than sensory defect (the alternative word 'alalia' is sometimes used)

Dyslexia

Difficulty in reading due to a defect of brain function other than sensory defect (the alternative word 'alexia' is sometimes used)

Dysmetria

Difficulty judging and controlling the speed

Dysphagia

Difficulty in swallowing

Dysphasia

Difficulty in using language. It can either be a problem understanding language (receptive) or speaking it (expressive). People are often affected by both sorts.

Dysphonia

Difficulty in voice production

Dyspraxia/Apraxia

Difficulty in controlling and co-ordinating movements or carrying out complex tasks when requested

Dyssomnia

Disorder in which the main complaint is about inadequate or unrefreshing sleep

Dystonia

Muscle tone fluctuates between stiffness and floppiness/slow twisting repetitive movements of arm