Preoperative Cognitive Training for Postoperative Cognitive Dysfunction

Postoperative Cognitive Dysfunction (POCD) is a state of decline in cognitive ability after surgery and is frequently seen among our elderly population. Many studies have looked into predictive risk factors for POCD while research is underway to search for pre-emptive measures to avoid this unfavourable outcome. Most will be looking at utilizing mobile software applications of cognitive training but in many poorer countries, owning electronic devices may not be an option or may be culturally less acceptable among the older patients. Hence, the investigators intend to investigate if a home-based logbook for cognitive training will reduce the incidence of POCD in a single centre study.

Background:

Postoperative Cognitive Dysfunction (POCD) is a state in which a decline in cognitive ability after surgery persist from early postoperative period to a much longer term. It is said to be a subtle disorder of thought processes that influences domains of cognition such as memory especially short-term memory, inattention and inability to focus with the presence of generalized slowness. In fact, a lot of older patients and their loved ones claim they are 'never the same' after the surgery. It is to be distinguished from postoperative delirium, a diagnosis portrayed through several symptoms that occurs acutely after surgery, fluctuates with time and has a tendency to be transient. POCD, on the other hand, is difficult to diagnose and only detected by comparing postoperative results of neuropsychological battery tests to those done as baseline preoperatively.

Advanced age is a major risk for developing POCD.6 Studies done by the International Study of Postoperative Cognitive Dysfunction (ISPOCD) group had found an incidence of POCD at 19.2% within 1 week and 6.2% in 3 months. Similar studies have reported a higher figure of 36.1% at 1 week after surgery for this phenomenon. In certain high-risk groups, the range ascends to 16 - 62% with an average of 35% in hip fracture patients9 and up to 60% for those who underwent cardiac surgery that persist in 10-30% after 6 months.

Hypothesis:

As far as research is concerned, tremendous efforts are now underway to look for causes of POCD and its risk factors but most importantly, find ways to avoid this disability over time. Clinicians instinctively prescribe prehabilitation in preparation for surgery through various physical conditioning to improve patients' physiological cardio-respiratory reserve in the hope for better recovery. The investigators hypothesize that the same holds true with cognitive function and by optimizing mental 'fitness', the pre-conditioning can attribute to a decrease in POCD.

Currently, there are a few ongoing trials such as NeuroBics in US15 for non-cardiac surgery and Cog-train in UK for cardiac patients investigating the role of using electronic-based 'brain' intervention before surgery. The investigators aim to test the feasibility of using a home based logbook with easy applicability as the cognitive training to produce equally favourable results in reducing POCD since the socio-economic pattern of our older population is different from the west. Senior citizens may not be familiar with or have difficulty to afford electronic devices and are less engaged with web-based Internet as reflected by data from a local service provider that found only 3.9% of their user base in the country is over the age of 60.

Sample size:

Based on 36% POCD at one week from a previous study8 and our proposed 50% reduction to 18% incidence with intervention, a total of 232 participants (including 10% drop-out rate) are required at a 1:1 ratio between groups to achieve an 80% powered study and Type 1 error of 5%.

A preliminary analysis will be done at 50 recruited patients to look for feasibility of continuing this study.

Eligibility Criteria:
Inclusion Criteria:

1. Aged 65 years of age or older, ASA I-III
2. Elective surgery (excluding neuro and cardiac surgery)
3. Date of surgery at least 10 days and up to one month from date of recruitment
4. Duration from induction of anaesthesia to end of anaesthesia minimum 2 hours
5. Expected post-operative hospital stay at least 48 hours
6. Able and willing to give informed consent
7. Literate
8. Willing to undergo cognitive and delirium assessments, perform daily cognitive training and able to return for follow-up assessments at 1 week, 3 months (phone call) and 1 year.

Exclusion Criteria:

1. Glasgow coma scale \< 15
2. Geriatric depression score (GDS-5) ≥ 2
3. Pre-existing psychiatric disorder or delirium
4. Severe visual, hearing or speech impairment
5. General anaesthetic within the last 6 months