|Sage. Photo: Monika Adamczyk; Agency: Dreamstime.com. |
"If any one faculty of our nature may be called more wonderful than the rest, I do think it is memory. There seems something more speakingly incomprehensible in the powers, the failures, the inequalities of memory, than in any other of our intelligences. The memory is sometimes so retentive, so serviceable, so obedient; at others, so bewildered and so weak; and at others again, so tyrannic, so beyond control! We are, to be sure, a miracle every way." —Jane Austen
Memory is the key to functioning throughout the day, the lynch pin in all our doing, relating, and learning. Without memory, every moment would be like our first. Consequently, memory impairment is a serious threat to well-being.
All of us experience occasional difficulties with memory; in younger people, it is usually transient, occurring under duress or in high-stress environments. With advancing age, though, age-associated memory impairment and early Alzheimer's dementia are more common, pervasive and troubling. Difficulty in remembering can create anxiety, which only worsens memory recall and creates a cycle of memory decline. A holistic approach to treating age-associated memory impairment needs to address neurotransmitter deficiencies as well as psychosocial and behavioral issues associated with impaired memory.
Mechanisms of Memory
There are several "types" of memory, each corresponding to a different part of the brain. For example, factual memory and declarative memory—where words can be used to describe something—are formed in the hippocampus area of the limbic system. Emotional memories are formed in the amygdala, also in the limbic system. Procedural memory—such as typing—requires the activity of the basal ganglia and cerebellum.
Acetylcholine (Ach) appears to be a key neurotransmitter in all the aforementioned memory functions. Ach is directly involved in memory formation in the hippocampus, and indirectly involved in memory formation in other areas of the brain through modulating N-methyl-D-aspartate (NMDA) receptor activity or altering neuron excitability.
Emotional stress and depression are common reasons for transient memory impairment. In cases of chronic memory impairment, think about hypothyroidism, cobalamine or folic acid deficiency, atherosclerosis, a history of hypoxic-ischemic events (myocardial infarctions, stroke, closed head injury, cardio-pulmonary bypass, prolonged status epilepticus).
Hypothyroidism and stress may impair memory by altering the long-term potentiation of neurons synapsing with the hippocampus, in effect slowing down access to memories (Gerges NZ. Brain Res. 2001 Dec 20; 922(2): 250–260). Folate upregulates production of neurotransmitters by increasing the availability of the omega-3 fatty acids, DHA and EPA. Folate levels are generally low in patients who suffer from chronic stress and/or depression, and this also affects production and function of Ach (Tolmunen T. J Nutr. 2003 Oct; 133(10): 3233–3236). A subset of depressed patients have elevated corticotropin-releasing factor which has been shown in animal and human studies to be responsible for many of the symptoms associated with depression (Plotsky PM. Psychiatr Clin North Am. 1998 Jun; 21(2): 293–307).
Lifestyle factors like chronic marijuana or alcohol consumption can alter memory formation. When taking a history, make sure to ask about this.
A number of widely-used medications can also impair memory, especially among the elderly, because drugs in general tend to have longer half-lives in older people. There are a number of drugs that have anticholinergic effects, even though they are not usually thought of as "anticholinergics." The antidepressant amitriptylene, antihistamines like diphenhydramine, and benzodiazepines such as diazepam are good examples. Rarer adverse memory effects may occur with drugs used to treat Parkinson's disease, such as metochlopramide and tacrine (Fick DM. Arch Intern Med. 2003; 163(22): 2716–2724).
The key to keeping a healthy memory is maintaining adequate amounts of Ach or preventing its rapid degradation by acetylcholinesterases in the synaptic clefts. Decreasing NDMA receptor activity may also prove to be a successful strategy. Finally, controlling oxidative damage from hypoperfusion and hypooxygenation states may also play an important role, especially in patients with frank neuro-degenerative disorders.
Medical Aromatherapy & Memory
Medical aromatherapy—the therapeutic use of pure essential oils derived from plants by steam distillation—holds great potential for nootropic (cognitive enhancement) therapy due to its rapid action, low cost, and ease of use for patients. Essential oils are a complex mixture of volatile compounds all under 350 atomic mass units (AMU) in weight, meaning that in addition to activating olfactory nerves in the nose, they are readily absorbed through the skin and across the alveolar-capillary interface.
Scent is powerfully linked to memory. Functional MRI scans have shown that essential oils can activate all the areas involved in memory processing in the brain (Cerf-Ducastel B, Murphy C. Brain Res. 2003 Oct 3; 986(1–2): 39–53).
It is interesting that Cerf-Ducastel's MRI study also showed that while there were no differences between young and old people in terms of the specific brain regions activated by olfactory stimuli, there were marked differences in degree of activation of the primary olfactory regions like the piriform cortex, entorhinal cortex and amygdala. This suggests an age-associated impairment of the sense of smell, begging the questions of whether this in some way correlates with age-associated cognitive impairment, and whether routine use of aromatherapy early on in the process might help to stave off both declines.
When most people think of essential oils, inhalation comes immediately to mind, and this is certainly the most common mode of use. The limitation of inhalation is that the effects are not as long lasting as when essential oils are taken internally. Medical grade essential oils can be safely taken orally in small doses, and there is a long history of their internal use for treatment of a wide range of disorders. (For more on this, join www.holisticprimarycare.net and read Intensive Essential Oil Therapy: Effective Treatment for Common Acute Infections.)
Animal studies suggest that 75% of the physiological effects of inhaling essential oils is from activation of the olfactory nerve versus 25% from secondary trans-alveolar absorption of bioactive volatile compounds into the blood stream (Komori T. Chem Senses. 2006 Oct; 31(8): 731–737). A more systemic effect requires oral administration.
The key to optimal treatment of memory impairment is to combine ingestion of certain essential oils with inhalation of others prior to tasks to improve memory and focus.
Essential Oils & Memory Formation
Sage (Salvia spp.) and Melissa (Melissa officinalis) essential oils address both the neurochemical mechanisms related to impaired memory as well as the psychological causes and effects related to memory impairment. Both have acetylcholine activity, anti-oxidant and anxiolytic effects and improve mood (Perry NS. J Pharm Pharmacol. 2000; 52(7): 895–902; Perry NS. CNS Drugs. 2006; 20(4): 257–280).
Three small-scale clinical studies with Sage essential oil, including 2 internal use studies, show improved speed, quality, and accuracy of memory (Perry NS. Pharmacol Biochem Behav. 2003; 75(3): 651–659; Tildesley NT. Physiol Behav. 2005; 83(5): 699–709; Tildesley NT. Pharmacol Biochem Behav. 2003; 75(3): 669–674). In adults with mild to moderate Alzheimer's dementia, global symptoms improved after 4 weeks of internal consumption. Healthy young volunteers showed measurable effects on cognitive function within hours of internal consumption. A double-blind placebo controlled trial using a tincture of Sage showed similar results (Akhondzadeh S. J Clin Pharm Ther. 2003; 28(1): 53–59).
A double-blind study comparing tincture of Melissa officinalis against placebo showed similar improvement in memory and mood within 2 hours of ingestion of the herbal extract (Kennedy DO. Pharmacol Biochem Behav. 2002 Jul; 72(4): 953–964).
Interestingly, essential oils that have GABA-ergic effects, such as Lavender, improve memory even though they can also have mildly sedating, soporific and anti-epileptic activity.
Improving Task Performance, Reducing Oxidative Stress
Inhalation of Rosemary (Rosmarinus officinalis) and Lavender (Lavandula angustifolia) has been shown in a clinical trial to improve mathematical task performance while reducing anxiety without making subjects feel drowsy (Diego MA. Int J Neurosci. 1998; 96(3–4): 217–224). Rosemary and Lavender essential oils are helpful in rapidly relieving anxiety and improving concentration.
Oxidative damage to the brain from chronic stress, hypoxia and hypoperfusion may also contribute to memory damage. Essential oils of Sage, Rosemary, Lavender and Melissa all possess anti-oxidant activity in vitro. There is one recent clinical study showing that inhalation of Lavender and Rosemary essential oils for 5 minutes, in concentrations as low as 0.001%, had significant anti-oxidant activity and reduced salivary cortisol levels (Atsumi T, Tonosaki K. Psychiatry Res. 2007; 150(1): 89–96).
Medical aromatherapy has many advantages as a treatment modality over encapsulated herbals and nutritional supplements. The concentrated nature of essential oils renders them effective at very small doses. The effect of the scents through the olfactory nerve allows for nearly instantaneous stimulation of neurologic activity without requiring ingestion and gastric absorption. However, the safe and gentle nature of essential oils allows for broad therapeutic safety across a range of clinical conditions and ages.
Medical Aromatherapy in Practice
Sage, Rosemary and Lavender essential oils are more cost-effective and easily obtained at high purity than Melissa, which is a semi-precious essential oil and often adulterated. Inhalation of pure Sage essential oil is a practical way to experience immediate, though short-term, benefit from the effects of essential oils. Be aware, however, that sometimes the intensity of undiluted oils can be irritating if held too close to the nose.
When treating people with memory problems, begin with a combined topical/internal approach. A topical blend of Sage, Lavender and Rosemary containing roughly 5–8% pure essential oils is usually effective. It can be applied directly to the skin, which will also allow the patient to inhale for about 5–10 minutes as the body heat gently evaporates some of the essential oils in the blend.
For mind and memory, the most convenient and effective place to apply the oils would be to the temples and forehead. This has two advantages: these sites are close to the nose, allowing for a longer period of inhalation, and because they are both highly vascularized and close to the brain, the essential oils are rapidly absorbed into circulation and into the brain.
Low concentrations like this are safe on the skin, and do provide some transdermal absorption. This is usually enough for the stressed-out college student or office worker experiencing transient memory deficits.
For sub-acute or chronic memory problems, internal administration of a combination of Sage, Lavender and Rosemary, for a minimum of 4–6 weeks may be able to improve memory by addressing the main neurochemical imbalances in the brain. One can take oral essential oils via gelatin capsules, by mixing them with food, or by simply swallowing a few drops followed by a warm water "chaser." Professional, physician-formulated medical aromatherapy blends are the safest way to deliver essential oils topically and internally at the same time.
Good memory function is essential for function in life, for recalling facts, and for maintaining close emotional relationships. Medical aromatherapy can be a cost-effective and easy treatment modality for memory impairment, appealing to patients and healthcare providers alike.
"The sense of smell, almost more than any other, has the power to recall memories and it is a pity that you use it so little." —Rachel Carson
Kamyar Hedayat, MD is a board-certified pediatrician and critical care physician with an active holistic medicine and clinical aromatherapy practice in Chicago. He is the founder and president of AromaMD, a company dedicated to making high-quality, scientifically-supported clinical aromatherapy products available to physicians and their patients. For more information, visit www.aromamd.net or call 866-472-7662.