26th June 2023

Localising the lesion

Symptoms can vary depending on the location of the brain lesion; commonly in MRCP, clues are given within the patient history to help to localise the lesion. Understanding the different functions of the lobes of the brain can help to identify the area likely affected prior to imaging. This is covered in more detail in the ‘Basic Neuroanatomy’ section.

Frontal lobe

The frontal lobe controls personality, speech fluency (via Broca’s area) and the coordination of movement (via the primary motor cortex). A lesion here may therefore cause motor weakness, changes in personality and problem solving, loss of smell or speech changes.

Parietal lobe

The parietal lobe is involved with coordination of sensory and spatial stimuli. It is the part of the brain that allows us to recognise faces and stores the memory for reading and writing. A lesion here may cause difficulty with spatial awareness, weakness or sensory changes, or astereognosis (inability to recognise objects by touch).

Temporal lobe

The temporal lobe is involved in speech comprehension (Wernicke’s area) and processing of sounds and memories. A tumour in this region can cause short term memory loss or language and speech difficulties.

Occipital lobe

The occipital lobe is involved in visual perception. A tumour located in this area may cause changes in vision, such as size, shape, visual deficits, and colour identification.

Cerebellum

The cerebellum controls balance, coordination, and posture. A tumour in this area may cause dizziness, ataxia, nystagmus, and nausea.

Brain stem

The brain stem controls important body functions such as breathing, swallowing, sneezing, and coughing.

Lobes of the brain.

Image Source: Wikimedia Commons (2016). 1306 Lobes of Cerebral CortexN, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:1306_Lobes_of_Cerebral_CortexN.jpg (Accessed on: 30 January 2023).