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2499 pages added, reviewed or updated during the last month (last updated: 19/4/2021)

2499 pages added, reviewed or updated during the last month (last updated: 19/4/2021)

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frontal lobe signs

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Frontal lobe signs are focal neurological signs that may help to indicate a frontal lobe lesion.

Related to precentral gyrus:

  • monoparesis or hemiparesis depending on extent of damage
  • focal motor seizures - either spreading with a Jacksonian march or rapid generalisation to give tonic-clonic seizures; status epilepticus is not an uncommon presentation of frontal lobe tumours

Related to Broca's area:

  • expressive/Broca's dysphasia if in dominant hemisphere

Related to supplementary motor area:

  • paralysis of head and eye movements to opposite side - head and eyes deviated towards side of lesion

Related to prefrontal area:

  • change in personality - inappropriate jocularity, loss of initiative and concern, akinetic mutism, disinhibition, general retardation
  • primitive reflexes - grasp, pout, palmar-mental, brisk jaw-jerk; changes in deep tendon reflexes contralaterally
  • unsteadiness in walking; rarely, gait apraxia
  • resistance to passive movements of the limbs - paratonia

Related to paracentral lobule:

  • incontinence of urine or faeces - cortical disinhibition

Orbital surface:

  • unilateral or bilateral anosmia

A patient with a frontal lobe space-occupying lesion on one side may cause optic atrophy in one eye, due to compression of the optic nerve, and papilloedema in the other eye, due to secondarily raised intracranial pressure - Foster Kennedy syndrome.

Last reviewed 05/2019