Patients
We performed 55 memory fMRI from January 2014 to December 2016 by using the Home Town Walking Paradigm in temporal lobe epilepsy (n=26),
temporal lobe tumours (n=21) and vascular malformations (n=8).
Sequences
The fMRI is performed on two consecutive days with a block design,
requiring mental navigation through one’s hometown by using landmarks given by patients themselves.
An EPI sequence was used with TR 3000ms,
TE 30ms,
in-plane resolution 3.9mm (64x64 matrix,
FOV 250 mm),
slice thickness 3mm (gap 25%) and 10 sets of Active-Baseline blocks. 3D MPRAGE sequence used for anatomical reference of activation areas and a field map to allow post processing.
Fig. 1: Home-town walk memory paradigm - 10 sets of Active-Baseline blocks. A stimulus is repeatedly presented for a block period of time (30 sec), followed by a period of ‘rest’ in which the haemodynamic response is allowed to return to a resting baseline. Brain activity is averaged across all trials within the block.
Information Sheets
A robust patient information sheet with examples of an imaginary walk is sent to patients with the appointment letter.
Fig. 2: Example of the patient information sheet along sent to patients with the appointment letter.
Fig. 3: Memory fMRI - Patient Information Sheet Example of Home Town Walking Paradigm
The patient was reminded one week before the appointment to practice the mental navigation task before coming for their fMRI scan. On attendance patients were called prior to their scan to hand in a prepared written record of their mental navigation task and to practise it before the scan if needed.
Fig. 4: Memory fMRI - Completed Patient Crib Sheet - 10 sections
Results - Memory fMRI 'Home town Walking Paradigm'
We obtained successful results in 46/55 patients with less than 20% failure rate.
70% of patients showed good activation on day 1 and 90% on day 2.
Examples of activation in a healthy volunteer and a patient are shown below.
Fig. 5: Memory fMRI - Home town walking paradigm showing bilateral activation in the para-hippocampal gyri, language and secondary visual areas in a healthy volunteer.
Fig. 6: Memory fMRI ‘Home Town Walk’ Paradigm Patient - Day one study shows activation areas in a right-handed patient.
Fig. 7: Memory fMRI ‘Home Town Walk’ Paradigm Patient - Day two study shows replication of activation areas.