MARGEN BÁSICO

3.2.1 Participant Recruitment: Patients were recruited from the accident and emergency and neurosurgery departments at Newcastle General Hospital. Patients were initially approached with information about the study while they were still inpatients. This approach was made in person by one of; the A&E staff, neurosurgery staff, the head injury specialist nurse or by Mr. Cowie following identification he made through discussions with hospital staff / examining the hospitals referral log. During this initial contact, effort was made to determine if the patient met the study’s inclusion criteria. If the criteria were met and the patient was interested they were then given the participant information sheet and a minimum of 24 hours, as per the ethics requirements for the experiment, to consider participating. Contact was re- made with them 24 hours later to follow up on their decision and informed consent was then taken if they had decided to take part. A scan booking at the Magnetic Resonance Centre (MR Centre) was made at the earliest opportunity. If this took place while the participant was still an inpatient they were accompanied by a member of the

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study team to the Centre. If they had been discharged then transport was arranged for them.

Patients were also made aware at the time of recruitment that they would be asked to return for a follow-up set of testing in 1 year. Patients were duly contacted by the study team 1 year later and asked if they would return. If they agreed to this, transportation was again arranged to the MR Centre and the exact same testing procedures were repeated. This marked the end of the patient’s involvement in the study.

Control subjects were recruited by poster and flyer advertising throughout the local community. In addition to this certain people / groups of people were approached in person, including a local young mothers group, students at a 6th _{form college (though} their teacher) etc. Members of the study team also asked people who they knew who they believed may be suitable for the study. These more direct methods of control recruitment were made in an effort to gain matched subjects.

3.2.2 Inclusion Criteria: Inclusion criteria were created to ensure both patient safety and high data quality. These criteria are outlined below in Table 3.1. Shaded cells indicate that the criteria is specific to patient participants only, while non-shaded cells apply to patient and control participants. Note that in addition to meeting these criteria, control participants were also matched to patients. More information on the matching criteria is provided in section 3.2.4.

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The minimum age limit was applied to avoid consent issues around testing children. Restricting the participant sample to adults is also beneficial in keeping all participants comparable to one another; research has frequently suggested that the response and recovery from TBI differs in children (Tavano et al., 2014, Taylor and Alden, 1997), implying that the study of them should be kept separate. An upper age limit was also selected for the same reason; older TBI patients have an increased likelihood of existing co-morbid conditions which may confound findings, such as deteriorating frontal white matter (Salat et al., 2005), and also have limited functional recovery following compared to younger adults (Mosenthal et al., 2004). It should be noted that one subject over this age (68 years) was recruited on the basis of their presentation otherwise being very suitable.

GCS of no less than 9 was chosen to avoid the recruitment of any severe

patients, supportive of the studies broader interests. However this criteria was relaxed during recruitment due to recruitment targets not being met. Due to this, one patient with a GCS of 7 was used in the study. This patient, H08 (Table 3.2), otherwise

demonstrated LoC and PTA durations well within the boundaries of moderate patients. Aged between 16 and 65

GCS 9 – 15

Scan able to be performed within 14 days of injury No previous history of serious head injury No previous history of neurological problems No previous history of psychological problems

(except depression in the case that it was treated by the GP alone) No history of substance abuse

No injury which would prevent the patient’s transfer to the MR Centre Fluent English speaker

No visual / auditory problems No contraindications to MR scanning

Table 3.1. A list of inclusion criteria for participants in the study. Cells with a shaded background

indicate that the criteria only apply to a patient participant while those without a shaded background apply to patients and controls.

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It was therefore deemed acceptable to include this patient within the “moderate” sub- group. It should be noted that testing described throughout Chapters 4-6 considers if the inclusion of this moderate sub-group has affected the validity of researching mild TBI.

In order to capture acute patient data, time from injury to scan was initially set to be no more than 6 days. However this criteria was also relaxed first to 10 days, and finally to 14, after being deemed too ambitious. Problems encountered with the original 6 day goal were reported to include logistical difficulties of the scanner being placed away from a clinical workplace and the lack of immediate medical support which came with this, making the movement and care of more injured patients difficult. All patients were scanned within 14 days of their injury.

Any participants with previous history of any neurological / psychological problems or substance abuse were excluded in order to avoid factors which would confound the study of the TBI in question alone. A neurological / substance abuse history may contribute to an abnormal brain scan, while a psychiatric history could impact upon cognitive performance. Further, participants who were not fluent in English or who had visual / auditory problems were also excluded so that cognitive performance scores would not be impacted by communication issues irrelevant to cognitive function. Finally, the study radiographer team assessed each participant to ensure it was safe to expose them to the MRI scanner.

3.2.3 Demographic Information: Demographic information was collected from each participant. For all participants (patients and controls), this information included:

 Age at time of scan

 Sex

 Employment status / occupation

 Educational level. This was categorised into 4 groups; o No qualifications

o GCSE or equivalent o A level / Diploma

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Additional information was collected from patients specifically, listed below:

 Any medications they were currently taking (this was asked as another means of ensuring that they met the inclusion criteria, e.g. a patient taking psychiatric medication would be excluded in case of them having an otherwise undisclosed mental illness)

 Mechanism of injury

 GCS on admission

 Presence / duration of Loss of Consciousness (LoC) and Post Traumatic Amnesia (PTA)

 If a headache was present

 If the patient had vomited

 If the patient had experienced any seizures

 Injuries other than to the head which had been sustained in the accident

 If a CT scan had taken place as part of their routine clinical care; if one had been performed then the findings from this were also taken

3.2.4 Control Matching: In addition to having to meet criteria outlined in Table 3.1, controls were matched to patients on age, gender and highest level of education. Age and gender were used to keep controls as physically matched to patients as possible, while highest level of education was used in an attempt to increase validity in neuropsychological comparisons between controls and patients.