As the worldwide population of older adults rapidly increases over the coming years, effective strategies are needed to help this population to maintain and enhance physical, cognitive, and psychological well-being. Up to 10% of community dwelling older adults have depressive symptoms in Europe. Older adults are also subject to chronic illnesses which further exacerbate psychological symptoms. Furthermore, normal aging is associated with decline in cognitive functioning. Given the prevalence of mental health problems and cognitive difficulties in older adults, mindfulness-based interventions (MBIs) could be helpful in this population. Accordingly, a growing number of studies suggest that mindfulness-based interventions in the elderly have beneficial effects on psychological health (decrease in depression, anxiety, sleep problems, and increase in general mood and positive affect) and cognition (enhanced attention, executive functions).

Electroencephalography (EEG) is a non-invasive technique which can be useful to study the neurophysiological correlates of mindfulness, and give neurobiological evidence of its beneficial effect in the elderly. Studies that examined spectral power outcomes between mindfulness and control state showed (i) increased alpha and theta power, as a marker of internally-directed attention processing and executive functioning and (ii) a shift towards left-sided anterior alpha activation, a pattern associated previously with positive emotions.

The aim of this study is to evaluate short and long-term cognitive, psychological, and physiological effects of a standard 8-week MBI in healthy older adults. Cognitive and psychological evaluations, and resting state EEG will be administered within 2 weeks prior to and within 2 weeks following MBI, and repeated 24 weeks following MBI.

Sixty older adults will be enrolled through local media announcements, meetings with elderly people organized in collaboration with local leisure and cultural associations, Alzheimer cafè, university of the third age, contacts with general practitioners. All participants will undergo cognitive and psychological evaluation and EEG. Moreover, current pharmacological therapies will be recorded and medical illness burden and comorbidity will be rated by the Cumulative Illness Rating Scale. Personality traits will be assessed by the Revised NEO Personality Inventory (NEO PI-R). The Subjective Cognitive Decline-Interview will be administered to evaluate the presence of subjective cognitive decline.

The EEG will be recorded (250 Hz sampling frequency, without filtering) with 19 standard electrodes positioned according to the international standard 10-20 in baseline conditions. The electrodes will have an impedance of less than 5 kiloohm. Recordings of 5 minutes with open eyes and 5 minutes with eyes closed will be performed. Following the acquisition of the signal, spectral analysis will be applied.

Mindfulness-based intervention is a standardized program which consists of 2-hour sessions that will be delivered at weekly intervals for 8 weeks in group setting. It is based on a comprehensive set of mindfulness practices derived from mindfulness-based stress reduction and mindfulness-based cognitive therapy programs, but specifically tailored to older adults. Participants will also be instructed to regularly engage in home mindfulness practice.

Follow-up: all participants will repeat cognitive and psychological evaluation and EEG after 2 weeks and after 24 weeks from the end of MBI.

Data analysis: Descriptive statistics on cognitive, psychological, and EEG variables will be done by using parametric and non- parametric tests. The analyses of correlation between different clinical variables (assessment tools) and EEG brain features will be assessed by linear and generalized linear models. For longitudinal analyses we will adopt the generalized estimating equation models.

Inclusion criteria:

• community-dwelling older adults
• age between 60 and 75 years
• normal cognition

Exclusion criteria:

• clinically significant depression or anxiety
• major neurological disorders (i.e., stroke, dementia or cognitive impairment, tumor)
• major psychiatric disorders (i.e., major depressive disorder, bipolar disorder, drug and alcohol dependence)
• chronic disease or acute unstable illness (respiratory, cardiovascular, digestive, renal, metabolic, hematologic, endocrine, infectious, or malignancy) which interfered with the aims of the study protocol.

The dataset analyzed in this article is publicly available at the Mendeley data repository