Psychology
2011. Vol.2, No.8, 846-852
Copyright © 2011 SciRes. DOI:10.4236/psych.2011.28129
The Effects of Neurofeedback Training on Memory Performance
in Elderly Subjects
Gaël Lecomte, Jacques Juhel
Centre de Recherche en Psychologie, Cognition et Communication,
Université Européenne de Bretagne Rennes, France.
Email: jacques.juhel@univ-rennes2.fr
Received April 29th, 2011; revised July 25th, 2011; accepted September 1st, 2011.
Neurofeedback or electroencephalographic operant conditioning (EEG-OC) is an EEG biofeedback technique
used to train individuals to control or modify their cortical activity through learned self-regulation. Initially used
for treating a variety of pathologies, neurofeedback has been employed more recently to improve the physical or
cognitive performance of human beings. The purpose of this study is to assess the hypothesis of the effect of
neurofeedback (the ‘awakened mind’ model) on the memory performance of subjects aged over 65. 30 partici-
pants were shared equally between 3 groups: an experimental group that underwent 4 neurofeedback training
sessions; a non-neurofeedback group trained at relaxation; and a ‘waiting list’ control group. Results showed
that the members of the Neurofeedback group learned to increase the spectral power of the alpha frequency
range as well as the alpha/thêta ratio, and that compared with the members of the two other groups, neurofeed-
back training resulted in a more pronounced decrease, albeit without any relation to changes in EEG activity and
the level of stress and anxiety of participants undergoing such training. Yet contrary to expectations, no im-
provement of memory performance (differed recall of words and learning of lists of words) was observed. These
mixed results, which suggest a wide range of applications, underline the need for a more systematic assessment
of the potential applications of NFB training in elderly humans in order to be better able to specify the effects of
the retained protocol on cognitive performance.
Keywords: Aging, Neurofeedback Training, Alpha Stimulation, Memory
Introduction
Neurofeedback training is based on the principle of operant
conditioning and involves informing the subject in real time
about the workings of their organism in order to incite them to
modify their behaviour. The term “biofeedback” is used when
the information provided concerns physiological parameters
such as body temperature, breathing rhythm and heart rate.
Biofeedback has been used for treating migraines (Nestoriuc, &
Martin, 2007), Raynaud’s disease (Katsamanis Karavidas, Tsai,
Yucha, McGrady, & Lehrer, 2006) and urinary incontinence
(Glazer & Laine, 2006). Neurofeedback training (NFB) or elec-
troencephalographic biofeedback (EEG) involves providing the
subject in real time with information relating to the rhythmic
cortical electrical activities that reflect the electrical activity of
specific cortical areas and functions (Evans, & Abarbanel, 1999;
Masterpasqua, & Healey, 2003). The aim of NFB is to enable
the subject to become aware of particular patterns of cortical
activity that we know or assume to be associated with a more
optimal behaviour or state. The information returned to the
subject in the course of an NFB session therefore pertains to the
activity of one or several frequency bands (delta: 0 - 4 Hz; thêta:
4 - 7 Hz; lower and upper alpha: 7 - 12 Hz; sensorimotor
rhythms: 12 - 15 Hz; beta: 15 -20 Hz; gamma: 30 - 80 Hz).
Feedback can be auditive and/or visual, more or less explicit
(graphic or video games/animations), presented continuously or
discontinuously, and can be based on fixed triggering thresh-
olds or adaptive thresholds associated with absolute target-
values (range of cortical waves) or relative target-values (for
example, the proportion of global activity).
Neurofeedback has been used for treating epileptic patients
(Sterman, & Egner, 2006) and subjects suffering from attention
deficit and hyperactivity disorders (Butnik, 2005), but also in
the treatment of addictions (Scott, Kaiser, Othmer & Sideroff,
2005), depression and anxiety (Hammond, 2005, 2006), and for
monitoring the after-effects of neurological lesions (Bearden,
Cassisi & Pineda, 2003) and treating cases of chronic pain in
elderly subjects (Middaugh & Pawlick, 2002). Several studies
have also focused on the effects of NFB on cognitive perform-
ance in healthy subjects (Budzynski, 1996; Egner & Gruzelier,
2004; Gruzelier, Egner & Vernon, 2006; Hanslmayer, Sauseng,
Doppelmayr, Schabus & Klimesch, 2005; Vernon, 2005;
Vernon, Egner, Cooper, Compton, Neilands, Sheri & Gruzelier,
2003).
The conceptualisation of NFB as an agent of cognitive
change is essentially based on the correlations observed be-
tween certain EEG frequency bands and various aspects of
information processing (Klimesch, 1999; Klimesch, Vogt &
Doppelmayer, 2000; Klimesch, Schack, & Sauseng, 2005;
Sauseng, & Klimesch, 2008). For example, thêta activity ap-
pears to be related to working memory processes and episodic
memory. It appears that lower alpha waves are largely associ-
ated with attentional processes, while upper alpha waves reflect
recovery proce sses in semantic memory. Bêta wave s associated
with motor activity are also assumed to be involved in the acti-
vation of attentional processes. Finally, gamma activity may
play a ‘universal’ role in sensory and cognitive processing
(Basar, Basar-Eroglu, Karakas, & Schürmann, 2000). The am-
plitude of lower frequency bands (delta and thêta) and upper
frequency bands (gamma) tends to increase in line with cogni-
tive effort while the amplitude of alpha and beta waves tends to
decrease (Basar, 2004; Basar, Basar-Eroglu, Karakas, & Schür-
mann, 2001). More recently, Sauseng, & Klimesch (2008) have
argued that phase synchronization (i.e. cohesion between corti-
G. LECOMTE ET AL.
847
cal sites, between oscillations of differing frequency, with ex-
ternal stimuli) may be the underlying neural mechanism in
certain cognitive processes. However, Sauseng and Klimesch
remark that “we do not know if the association between
physiological mechanisms and cognitive functions is correla-
tional or causal [...] even if the results of several psychophar-
macological and clinical studies suggest attributing a causal
role to phase synchronization in information processing” (p.
1010).
The above remarks point to the application of NFB training
protocols targeting frequency bands related to the cognitive
functions that are deemed to require improved efficiency. Yet
the complexity of the relations between EEG activity and cog-
nition means that it is extremely difficult to clarify a priori the
cognitive objectives of an inhibition or stimulation protocol of
the activity of a given frequency band (thêta, alpha or bêta
training). This clarification is even more problematic in the case
of training protocols in which the participant must learn to am-
plify a level of activity (e.g. thêta) in conjunction with the inhi-
bition of another (e.g. delta). Although results may sometimes
be uncertain, observations of young adults and a number of
findings drawn from studies of elderly subjects suggest several
hypotheses.
Bauer (1976) was the first to study the effect of 4 NFB ses-
sions (alpha stimulation) on short-term memory in young adults.
The results showed an increase of alpha activity but did not
point conclusively to an effect of NFB on memory performance.
More recently, Vernon et al. (2003) studied the effects of two
different NFB training modalities on the performance of young
adults in a memory task involving semantic work (conceptual
span paradigm) and in a visual attention task (continuous per-
formance paradigm). The first training condition was a stimula-
tion of thêta waves (4 - 7 Hz, in connection with working mem-
ory) and an inhibition of delta waves (<4 Hz, associated with
sleep) and alpha waves (8 - 12 Hz, associated with physical
relaxation). The second training condition simultaneously in-
cluded a stimulation of SMR waves (12 - 15 Hz, associated
with attention) and an inhibition of bêta waves (18 - 22 Hz,
associated with problem-solving, and also sometimes anxiety
disorders). Subjects took part in 8 individual sessions with
feedback in the form of a video game. The observations drawn
from the bêta-SMR condition chiefly highlighted an NFB
learning process and a significant improvement of performance
in the task involving semantic working memory and to a lesser
extent in the attention task. The observations drawn from the
stimulation condition of thêta waves and from the inhibition of
alpha waves did not indicate any changes of EEG activity or of
the level of cognitive performance. However, Hanslmayer et al.
(2005) showed that alpha/thêta training (alpha stimulation, thêta
inhibition) may result in an improvement of cognitive per-
formance (mental rotation task) in participants capable of
learning to increase the alpha/thêta ratio. It appears therefore
that NFB training that simultaneously targets several objectives
in relation to the frequencies that make up the initial profile of
cortical activity and that simultaneously restitute information
relating to several frequency bands (particularly thêta and alpha)
may prove to be eff icient, at least in ‘responsive’ individuals.
Although it has been clearly established that ageing involves
a decrease of EEG activity (Obrist, 1954) and a decrease of the
power of the alpha band (Markand, 1990), very few studies
have so far focused on the impact of NFB on EEG activity and
the cognitive performance of elderly subjects (Albert, Andrasik,
Moore, & Dunn, 1998; Angelakis, Stathopoulou, Frymiare,
Green, Lubar, & Kounios, 2007; Fernandez, Becerra, Roca,
Espino, Bahlke, Harmony, Fernandez-Bouza, Belmont, & Diaz-
Comas, 2008). The only study in the area is by Angelakis et al.
(2007), who target peak alpha frequency (PAF), which meas-
ures the discrete frequency of maximum amplitude in the alpha
band. The PAF is known to be weaker in children and elderly
individuals, and is also weaker in individuals suffering from
Alzheimer’s disease than it is in healthy subjects (Klimesch,
Vogt & Doppelmayer, 2000). The PAF is also correlated posi-
tively (independently of age) with the intellectual level of
healthy individuals or of individuals suffering from neurologi-
cal disorders (Angelakis, Lubar, & Stathopoulou, 2004). Ange-
lakis et al. (2007) administered over 30 NFB sessions to 6 indi-
viduals aged 70 to 78. Three of the subjects underwent a train-
ing process aimed exclusively at increasing the PAF (experi-
mental condition). Two other participants underwent an NFB
protocol aimed at increasing the amplitude of alpha waves (8 -
13 Hz) (control condition 1). The sixth participant underwent a
pseudo-NFB protocol (control condition 2: restitution based on
the recorded EEG activity of another subject). Assessments of
EEG activity at rest and during cognitive activities involving
attentional control (number span, Stroop test, Raven’s matrices,
etc.) were conducted before and after the series of NFB ses-
sions. Angelakis et al. (2007) observed an increase of PAF,
which was particularly pronounced in frontal areas, in 2 of the 3
participants of the experimental condition and an increase of
alpha activity in the 2 participants of the control condition. In
parallel, the results of the cognitive assessments indicate that
NFB PAF training improves the speed of information process-
ing as well as the resistance to interference; training the ampli-
tude of the alpha waves improves memory performance. These
initial results are compatible with the hypothesis of a positive
impact of NFB (stimulation of alpha waves) on the cognitive
performance of elderly subjects. This effect could be explained
by the facilitating role performed by the slower rhythms in the
connections between different cortical areas (Gruzelier, Egner,
& Vernon, 2006).
The aim of this research was to examine these initial findings
in the light of the observations of elderly subjects trained spe-
cifically to increase the power of the upper alpha frequency
band (10 - 12 Hz) in comparison with the power of the thêta
band (4 - 7 Hz) (Hanslmayer et al., 2005). The NFB training
sessions undergone by participants in the experiment were ex-
pected to generate two chief observations: first of all, a change
of EEG activity resulting in an increase of the alpha/thêta ratio;
secondly, an improvement of cognitive performance, measured
in this case in the area of short-term memory.
Method
Participants
Thirty subjects (23 women and 7 men aged 75.25 on average,
age range: 65 to 85) took part in this study. The participants,
who all lived at home, presented no known neurological or
psychiatric antecedents or any known psychological disorder.
None of the participants had undergone psychotropic treatment.
Normality of performances in the Mini Mental State Examina-
tion (MMSE) was also required to minimize the probability of
an inclusion of emerging degenerative pathologies.
Procedure
The experiment design and data collection procedure incor-
porated recent recommendations concerning the need to have
EEG measurements in pre- and post-tests and the need to in-
G. LECOMTE ET AL.
848
clude a non-contingent control group (Vernon, 2005). Partici-
pants were shared randomly between an experimental group, a
control group and a test/retest group of equal sizes. On 4 sepa-
rate occasions every week, the members of the experimental
group (NFB) and of the control group (RELAX) were studied
individually for approximately 1 hour. The content of each
session varied according to the condition: a) experimental: 5-
minute preparation, 30-minute NFB training session, 5 minutes
for removal of captors and recovery; or b) control: 5-minute
warm-up, 30-minute dynamic relaxation session (simple yoga
movements) and static relaxation (return to rest), 5-minute re-
covery. The session ended with a rapid self-assessment of the
anxiety experienced by participants and of the stress generated
by the situation (5 minutes) followed by a debriefing session
lasting approximately 10 minutes. The assessment of cognitive
performance was conducted before session 1 (20 minutes) and
was repeated after session 4. The third group (the “waiting list”
group) was a test/retest group (TRT). The subjects placed in
this condition took part in all the evaluations (first cognitive
evaluation, self-assessment of stress and anxiety once a week
and on 4 separate occasions, second cognitive evaluation) but
did not benefit from any particular intervention.
Psychological Assessment
Cognitive performance in the area of memory was assessed
by 2 of the 3 memory tests drawn from the Signoret Memory
Battery (Signoret, 1996). The first test, known as the ‘Recall’
test (REC), involved a delayed recall of 6 images (after resolu-
tion of 6 arithmetic and verbal problems and a semantic fluency
test). The second test, known as the ‘learning’ test (LEA), as-
sessed the ability to memorize a list of 8 words immediately
and the improvement of performance through repetition. The
correlation between these tests was moderate (r = .409) on a
sample of 50 elderly. Both tests were rated on a 12-point scale;
the total number of points scored by participants could there-
fore amount potentially to 24. The level of stress generated by
the situation and the level of anxiety experienced during the
session were evaluated using a non-graduated Visual Analogi-
cal Scale (0 - 10) with a recall of the preceding self-assessment.
Both scores were then combined into one single score or ‘ten-
sion level’ (TENS).
EEG Data Collection and Neurofeedback Protocol
The collection of NFB data was conducted using the Pen-
dant® EEG system and BioExplorer software for the purposes
of recording and controlling/monitoring in real time. The
analyses and return in the form of graphic animations and audi-
tive signals correlated with cortical activity and the optimal
profile of targeted activity were carried out using the BioRe-
view sub-module provided by BioExplorer. Two pairs of cap-
tors were set up transversally: C3-Cz/Cz-C4, where Cz repre-
sents the reference points at the top of the skull; C3 and C4
represent the measurement sites in the middle of each hemi-
sphere.
The training protocol used in this study targeted the cerebral
activity of individuals who are expert practitioners of medita-
tion (Cade, & Coxhead, 1979). The practice of meditation aims
to develop the ability to activate a conscious self-regulation of
sensory and motor aspects of the physical body. When per-
formed on a regular basis, this practice appears to have a posi-
tive impact on attention span (Brefczynski-Lewis, Lutz, Schae-
fer, Levinson & Davidson, 2007) and on synchronization be-
tween cerebral areas in the gamma frequency bands (30 - 70 Hz)
that correspond to the completion of metacognitive tasks in
which self-regulation plays a key role (Lutz, Greischar,
Rawlings, Ricard & Davidson, 2004; von Stein, Chiang, &
Konig, 2000). The NFB protocol therefore aimed to harmonize
the different ranges of cerebral waves with a view to tending
towards an optimal reference model that describes the chief
characteristics of the cerebral profile of experts in meditation
(the so-called ‘awakened mind’ model; see Figure 1). It in-
volved a combination of four pairs of filters in comparative
mode (5 minutes for each), with one of these comparisons
stimulating alpha waves in relation to thêta waves and another
comparison inhibiting thêta waves in relation to slow bêta
waves.
The stimulation process was conducted using a continuous
sound signal (eyes closed) and a video animation on replay
(eyes open) so long as it remained within an amplitude range
enabling the subject to direct, for each of the generated ranges
of cortical waves, the respective proportions of the different
wave ranges towards the targeted waves. The sound feedback
(continuous sound replay) and visual feedback (replay of video)
were triggered whenever the conditions of the filters were satis-
fied simultaneously. The program automatically adjusted the
triggering threshold according to the rate of success of the par-
ticipant in order to avoid causing a sense of frustration or fail-
ure, while gradually increasing the level of demand of the trig-
gering thresholds.
The relation between the spectral powers of the alpha and
thêta bands measured during sessions 1 and 4 were computed as
follows. The first three minutes of EEG data were collected at
the beginning of session 1 and 4 and were then processed by
normalizing the specific powers of the higher alpha frequency
bands (10 - 12 Hz) and thêta frequency bands (4 - 7 Hz) and by
relating them to the power of the signal for all frequencies be-
tween 2 Hz and 49 Hz while extracting the noise caused by
electromagnetic parasites on either side of the band. 250 seg-
ments were used based on the Fast Fourier Transform algorithm,
with a resolution of .5 Hz. The average alpha/thêta ratio for the
channels assigned to C3 and C4 (with reference in Cz) were
then computed
Statistical Analysis
Since the NFB group included just 10 participants, the im-
pact of NFB on EEG activity was assessed using the exact
Wilcoxon test (unilateral test) by comparing the observations
made in session 4 (spectral power of alpha and thêta frequency
bands, relation between these spectral powers) with the obser-
vations drawn from session 1. For every member of the NFB
group, we also computed an index measuring changes in EEG
activity in comparison with the average change observed in all
(a) (b)
Figure 1.
a) Example of a pattern of electrical activity of the brain; b) Optimal
targeted pattern (“Awakened Mindmodel).
G. LECOMTE ET AL.
849
the other participants within the group. The index we used was
the Reliable Change Index (RCI), defined by Jacobson &
Truaux (Maassen, 2004), a statistical indicator of centered and
reduced normal distribution.
The assessment of the impact of NFB on memory perform-
ance was conducted using a MANOVA with repeated meas-
urements (2 dependent variables: REC and LEA; 1 between-
subjects factor with 3 modalities: NFB, RELAX and TRT; 1
within-subjects factor with 2 modalities: session 1 and session
4). The null hypothesis of evolution of memory performance
identical to the one observed on average in members of the
TRT group was tested in every member of the NFB group using
the RCI. Finally we used an ANOVA with repeated measure-
ments (1 between-subjects factor with 3 modalities: NFB,
RELAX and TRT; 1 within-subjects factor with 4 modalities:
sessions 1 to 4) to evaluate the evolution of tension level. The
significance threshold retained for all the statistical analyses
was fixe d at .05.
Results
We began by verifying that members of the experimental
group (NFB), of the control group (RELAX) and of the test/
retest group (TRT) had the same average age, F(2.27) < 1, p
> .05, and the same initial level of performance in the ‘recall’
and ‘learning’ tests, F(4.52) = .970, p > .05. Some scores in
deficit by 8 (non deficit limit score = 9/12; Signoret, 1996)
were observed in the REC1 test (NFB: indiv_9; RELAX: in-
div_11, indiv_16, TRT: indiv_23) and in the LEA1 test (TRT:
indiv_25).
The analysis of the evolution of the spectral powers of the
alpha and thêta frequency bands from session 1 to session 4
highlighted a significant increase of the spectral power of the
alpha band, z = 1.89, p = .031 and an increase of the alpha/
thêta relation between the 2 sessions, z = 2.09, p = .019, though
no increase of the spectral power of the thêta band was ob-
served, z = 1.22, p > .05. The analysis of individual change (see
Table 1) indicated that an increase of the spectral power of the
alpha frequency band was observed in 8 participants, that a
decrease of the spectral power of the thêta frequency bands was
observed in 6 participants and that an increase of the alpha/thêta
ratio was observed in 7 participants. These results are indicative
Table 1.
Individual changes between sessions 1 and 4 for alpha and theta fre-
quency band spectral power as well as for alpha/thêta ratio in NFB-
group. The Reliable Change Index (RCI) was computed for every par-
ticipant in comparison with remainder of the NFB-group participants
(*: significant change (p < .05): more important than mean change of
remainder of the group).
RCI
Participant alpha theta alpha/theta
1 .045 –1.914* 1.206
2 1.149 .423 1.286
3 1.874 –1.778* 1.228
4 .819 1.881* –.112
5 .737 .847 –.074
6 2.052* –1.234 1.174
7 .656 –2.015* .56
8 –.891 –2.572* 8.578*
9 .901 –1.653* 2.590*
10 –.988 1.462 –.393
of the inter-individual heterogeneity that subtends the changes
of EEG activity such as they might be summarized at the level
of the NFB group, with certain participants (1, 2, 3, 6, 7 and 9)
appearing to be more capable (4, 5, 8 and 10) of modifying
their EEG activity than others in the direction encouraged by
the training protocol.
Table 2 shows the average performance in the memory tests
for each group and at each measurement. Overall an improve-
ment of memory performance was observed in the members of
all 3 groups, F(2.26) = .376, p = .000, eta2 = .624 [univaried ef-
fects: a) REC1 vs. REC2, F(1.27) = 23.364, p = .000, eta2 = .464;
b) LEA1 vs. LEA2, F(1.27) = 23.351, p = .000, et a 2 = .463]. By
contrast, no significant effect of group x memory performance
interaction was demonstrated, F(4.52) = .720, p > .05.
In order to analyze the evolution of memory performance in
every member of the NFB group compared with the average
memory performance observed in members of the TRT group,
we initially confirmed that the hypothesis of equal variances
between the two sessions was respected in the TRT group, both
for REC, t(8) = .138, p > .05 and for LEA, t(8) = 1.620, p > .05.
Two RCIs—one for REC and one for LEA—were then com-
puted for every member of the NFB group. The ten individual
(NFB) vs. group (TRT) comparisons indicated that the memory
performance of several members of the NFB group increased
significantly more than the average increase of memory per-
formance observed in members of the TRT group. This result
was observed in several participants both for REC (indiv_2:
RCI = 2.128, p = .021; indiv_5: RCI = 2.122, p = .022, indiv_7:
RCI = 2.935, p = .003; unilateral test) and for LEA (indiv_2:
RCI = 2.367, p = .012; indiv_6: RCI = 3.328, p = .001; indiv_8:
RCI = 2.367, p = .012; unilateral test). However, increased
performance in both memory tests was only significant in one
member of the NFB group (indiv_2). As for the connections
between changes in EEG activity and improved performance in
either me mory test, we obse rved no relation between these two
variables (phi = 0, p = 1.000), nor did we observe, more spe-
cifically, any increase of the alpha/thêta ratio in the 5 members
of the NFB group who demonstrated a significant increase of
their performance in either memory test, z = 1.753, p = .063.
Finally, Figure 2 shows the evolution of the mean tension
level during the 4 sessions. The results did not highlight any
difference in the initial level of the 3 groups, F(2.27) = .765, p
> .05, although they do point to a significant decrease of the
tension level throughout the sessions, F(3.81) = 27.639, p
= .000, as well as a significant group x session interaction effect,
F(6.81) = 3.154, p = .000. The post-hoc comparisons helped to
account for this interaction effect by the significant decrease of
the tension level in the NFB group, F(1.27) = 45.99, p = .000,
and the slightly less pronounced decrease in the RELAX group,
F(1.27) = 17.415, p = .000, compared with the stable tension
level observed in the TRT group, F(1.27) = .55, p > .05. Finally,
the correlation observed between the increase of the al-
pha/thêta ratio and the decrease of the tension level between
sessions 1 and 4 could not be demonstrated for members of the
Table 2.
Pre- and post-training mean performance (standard deviation in
brackets) in the two memory tasks (“Recall and Learning”) for the
NFB, relaxation, and control groups.
“Recall” “Learning”
Group Session 1 Session 4 Session 1 Session 4
Neurofeedback10.00 (1.33 )11.10 (.99) 10.50 (1.08) 11.50 (.71)
Relaxtaion9.80 (1.48)10.90 (1.20) 10.80 (1.14 ) 11.50 (.85)
Test/retest 9.80 (1.14)10.40 (1.17) 10.40 (1.27) 11.10 (1.10)
G. LECOMTE ET AL.
850
0
1
2
3
4
5
6
7
8
9
1234
Tension level (VA scale : 0-20)
Session
Neurofeedback RelaxationTest/retest
Figure 2.
Mean tension level (stress and anxiety) across the four sessions for the
NFB-, relaxation- and waiting-list groups.
NFB group, r = .387, p > .05.
Discussion
We have examined the effects of the original training proto-
col of 4 NFB sessions on memory performance in elderly sub-
jects in good health. The experimental control included 2 con-
trol conditions—a so-called relaxation condition and another
condition with no particular intervention aiming to assess the
test-retest effect on memory performance and tension level.
The first issue was to establish whether the NFB training
process that aimed to foster a harmonization of the different
ranges of cortical waves in order to tend towards an optimal
model of cerebral activity could cause pronounced EEG
changes in subjects who had benefitted from it. Considering
that memory performance in young adults at rest is related
positively to the spectral power of upper alpha waves and re-
lated negatively to the spectral power of thêta waves (Hansl-
mayer et al., 2005; Klimesch, 1999; Klimesch, & Vogt, 2000),
our objective was to train the elderly members of the NFB
group to modify both wave ranges in relation to other frequency
bands. Analyses showed that NFB training resulted on average
in an increase of the spectral power of the upper alpha waves
and in an increase of the alpha/thêta ratio. This result needs to
be qualified by the fact that the expected changes in EEG activ-
ity were not observed in 4 of the 10 members of the NFB group.
Our findings corroborate earlier studies carried out on young
adults, that had failed to demonstrate any relation between NFB
training and ‘learned’ changes of EEG activity (Egner, & Gru-
zelier, 2004; Vernon et al., 2003).
Yet our results indicate that an elderly individual can be
trained to modify the amplitude of certain wave ranges and to
regulate brain EEG activity more ‘efficiently’. Our findings
therefore corroborate earlier results pertaining to young adults
(Hanslmayer et al., 2005) and elderly adults (Angelakis et al.,
2007). In a study of 18 young adults, Hanslmayer and col-
leagues observed that 5 participants had learned to increase the
power of the upper alpha waves, that 6 participants had learned
to decrease the power of the thêta waves, that 4 participants had
learned to do both and that 3 had failed to learn either (i.e. the
non-responders). Angelakis and collaborators (2007) made
similar observations in elderly individuals in a study based on a
high number of training sessions (between 31 and 36 sessions).
They observed that 2 of the 3 members of the experimental
group had gradually learned to increase the frequency of peaks
of alpha rhythms and that the 3 members of the control group
had also learned to increase the amplitude of the alpha waves. It
is important to note that in spite of the limited number of train-
ing sessions undergone by the subjects involved in the present
study, over half of them did learn to increase the spectral power
of the upper alpha waves and to reduce the spectral power of
the thêta waves.
Once this result had been established, the second issue was to
determine whether the NFB used to increase the spectral power
of the upper alpha waves and to reduce the spectral power of
the thêta waves could lead to an improvement in the cognitive
performance of elderly subjects. The alpha waves—particularly
the upper alpha waves—have a functional significance in
memory processes (Klimesch, 1999; Klimesch et al., 2005), and
recent findings suggest that fostering the amplitude of alpha
waves could have positive effects on the performance of elderly
subjects in a verbal memory task (Angelakis et al., 2007). Con-
trary to expectations, the observations made in the course of
this research do not corroborate this hypothesis. Of course, we
observed an improvement in the level of memory performance
of NFB group members—albeit an improvement of the same
amplitude as the one observed in the ‘relaxation’ group mem-
bers and in the ‘waiting list’ group members.
It appears therefore that this improvement is not indicative of
a mere effect of practice. We also established that the EEG
activity of elderly subjects in the NFB group whose memory
performance improved significantly in comparison with the
memory performance of members of the ‘waiting list’ group
had not changed in the way predicted by an effect of NFB. The
improved memory performance observed in several members
of the NFB group cannot be attributed therefore to changes in
the spectral power of upper alpha waves or of thêta waves
which NFB training might have enabled. The hypothesis of a
relation between NFB training and improved memory per-
formance in elderly subjects is not therefore corroborated by
the predicted empirical support.
Envisaged incidentally, the decrease of perceived stress and
anxiety in elderly members of the NFB group in the course of
the training sessions was a secondary result indicating that in
spite of the initial stress generated by the training mechanism,
NFB training results in a decrease of the tension level and in an
increase of the degree of relaxation in subjects benefitting from
such training. In fact, no difference between the tension level of
members of the NFB group and the tension level of members of
the relaxation group was observed at the end of the four indi-
vidual sessions. Yet NFB training currently has the status of a
‘probably efficient’ method for treating anxiety disorders
(Moore, 2000). Often conducted with eyes closed and with
auditive feedback in patients suffering from anxiety disorders
(Hammond, 2006), NFB training is relatively similar to a
meditation-based training method that uses sophisticated tech-
nology. The NFB training technique used in this research could
therefore be useful in the treatment of stress and anxiety in
elderly individuals (Ayers, Sorrell, Thorp, Loebach, & Wetherell,
2007), and, as several recent studies have begun to suggest
(Andrealotti, Veratti & Lachman, 2006; DeLuca, Lenze, Mul-
sant, Butters, Karp et al., 2005), it may thereby help to reduce
or postpone the process of cognitive decline associated with the
normal ageing process.
Yet this research does imply several limitations that explain
why stimulating alpha waves by NFB training appeared to have
no discernable effect on short-term memory in the elderly sub-
jects who took part in this study. Concerning the defined objec-
tives, the number of training sessions undergone by participants
is possibly insufficient. While earlier studies have been based
G. LECOMTE ET AL.
851
on 4 or 5 NFB sessions, studies in this research area are often
based on approximately ten training sessions (Egner, & Gruze-
lier, 2004; Vernon et al., 2003) and the most compelling effects
of NFB on cognitive performance were observed when partici-
pants were subjected to an even greater number of training
sessions (Angelakis et al., 2007). The relative small size of the
sample also limits the significance of the results by reducing
statistical power and thereby increasing the probability of fail-
ing to highlight a statistically significant difference, despite the
fact that such a difference did in fact exist. Another limitation
of this research is related to the good overall level and relative
homogeneity of memory performance displayed by participants,
one potential effect of which is a decrease of the chances of
observing an improvement of memory performance. Finally,
the type of task used in this research to assess memory per-
formance may have been insufficiently matched with the cogni-
tive processes associated with the frequency of wave ranges
targeted by NFB training.
Conclusion
NFB training provides a field of inquiry and potential appli-
cations that we are only just beginning to explore in the case of
elderly subjects. The present study illustrates this by showing
that it is possible to train an elderly subject to modify the am-
plitude of certain wave ranges according to the optimal model
of regulation of EEG activity using an original NFB protocol
targeting several wave ranges. Currently, we know that the
relations between specific patterns of EEG activity and levels
of cognitive performance also require considering NFB as a
training technique aimed at encouraging an elderly individual to
produce specific patterns of cortical activity in connection with
an improved level of cognitive performance. This research
avenue, which few have so far ventured down, has tended to
generate conflicting results (Bauer, 1976; Angelakis et al.,
2997). Our own observations do not corroborate the hypothesis
of the effect of NFB training of different frequency ranges (in
particular a stimulation of alpha waves) on memory perform-
ance in elderly subjects. A more rigorous and more systematic
assessment of the effects of NFB training on cognitive per-
formance in elderly subjects is therefore required to improve
our understanding of the conditions of application of the dif-
ferent NFB protocols that are applicable to this particular group,
to specify the possible indication and to better specify the ef-
fects on memory performance.
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