Director of Research
Heidi’s research interest lies in exploring how the human central nervous system adapts to its environment, a process known as neural plasticity. Her current line of research explores these central neural effects of chiropractic care and its impact on human function and quality of life.
Haavik H. (2014) The Reality Check: A quest to understand chiropractic from the inside out. Haavik Research, Auckland, New Zealand
Subclinical recurrent neck pain and its treatment impacts motor training-induced plasticity of the cerebellum and motor cortex
Baarbé, J. K., Yielder, P., Haavik, H., Holmes, M. W., & Murphy, B. A. (2018)
PloS one, 13(2), e0193413
Association of Subclinical Neck Pain With Altered Multisensory Integration at Baseline and 4-Week Follow-up Relative to Asymptomatic Controls
Farid, B., Yielder, P., Holmes,M., Haavik H., Murphy, B.A. (2018)
Journal of Manipulative and Physiological Therapeutics. 41(2); 81–91
Posture modulates the sensitivity of the H-reflex
Interexaminer reliability of a multidimensional battery of tests used to assess for vertebral subluxations
Holt, K., Russell, D., Cooperstein, R., Young, M., Sherson, M., Haavik, H. (2018)
Chiropractic Journal of Australia, 46(1), 101–117
The effects of a single session of spinal manipulation on strength and cortical drive in athletes
Christiansen, T. L., Niazi, I. K., Holt, K., Nedergaard, R. W., Duehr, J., Allen, K., Marshall, P., Türker, K.S., Hartvigsen, J. & Haavik, H. (2018)
European Journal of Applied Physiology, 1-13
Interexaminer reliability of seated motion palpation in defined spinal regions for the stiffest spinal site using continuous measures analysis
Holt, K., Russell, D., Young, M., Sherson, M., Haavik, H. (2017)
Journal of Manipulative and Physiological Therapeutics
Pelvic floor functional changes with spinal manipulation in pregnant and non-pregnant women: A pilot study
Haavik H, Kruger J & Murphy B (2016)
Ultrasound in Obstetrics & Gynecology
Influence of subclinical neck pain of the ability to perform a mental rotation task: A 4-week longitudinal study with a healthy control group comparison
Julianne K. Baarbé, Michael W.R. Holmes, Heather E. Murphy, Heidi Haavik, and Bernadette A. Murphy (2016)
Journal of Pediatric, Maternal & Family Health – Chiropractic ~ Volume 2016 ~ Issue 1
Objective: Mental rotation of objects and the frame of reference of those objects are critical for executing correct and skillful movements and are important for object recognition, spatial navigation, and movement planning. The purpose of this longitudinal study was to compare the mental rotation ability of those with subclinical neck pain (SCNP) to healthy controls at baseline and after 4 weeks.
Methods: Twenty-six volunteers (13 SCNP and 12 healthy controls) were recruited from a university student population. Subclinical neck pain participants had scores of mild to moderate on the Chronic Pain Grade Scale, and controls had minimal or no pain. For the mental rotation task, participants were presented with an object (letter “R”) on a computer screen presented randomly in either normal or backwards parity at various orientations (0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°). Participants indicated the object’s parity by pressing “N” for normal or “B” for backwards. Each orientation for normal and backward parities was presented 5 times, and the average response time for all letter presentations was calculated for each participant, at baseline and 4 weeks later.
Results: Both groups had overall improved response times from baseline to 4 weeks. Healthy participants had significantly improved response times compared to SCNP, both at baseline (P b .05) and 4 weeks (P b .05).
Conclusions: Healthy participants performed better than the SCNP group at both time points. Subclinical neck pain may impair the ability to perform a complex mental rotation task involving cerebellar connections, possibly due to altered body schema. (J Manipulative Physiol Ther 2016;39:23-30)
Key Indexing Terms: Cerebellum; Adult; Body Schema; Humans; Neuropsychological Tests; Space Perception; Visual Perception; Mental Processes
Induction of long-term depression-like plasticity by pairings of motor imagination and peripheral electrical stimulation
Jochumsen M, Signal N, Nedergaard RW, Taylor D, Haavik H and Niazi IK (2015)
Front. Hum. Neurosci. 9:644
Long-term depression (LTD) and long-term potentiation (LTP)-like plasticity are models of synaptic plasticity which have been associated with memory and learning. The induction of LTD and LTP-like plasticity, using different stimulation protocols, has been proposed as a means of addressing abnormalities in cortical excitability associated with conditions such as focal hand dystonia and stroke. The aim of this study was to investigate whether the excitability of the cortical projections to the tibialis anterior muscle could be decreased when dorsiflexion of the ankle joint was imagined and paired with peripheral electrical stimulation of the nerve supplying the antagonist soleus muscle. The effect of stimulus timing was evaluated by comparing paired stimulation timed to reach the cortex before, at and after the onset of imagined movement. Fourteen healthy subjects participated in six experimental sessions held on non-consecutive days. The timing of stimulation delivery was determined offline based on the contingent negative variation (CNV) of electroencephalography (EEG) brain data obtained during imagined dorsiflexion. Afferent stimulation was provided via a single pulse electrical stimulation to the peripheral nerve paired, based on the CNV, with motor imagination of ankle dorsiflexion. A significant decrease (P=0.001) in the excitability of the cortical projection of tibialis anterior was observed when the afferent volley from the electrical stimulation of the tibial nerve (TN) reached the cortex at the onset of motor imagination based on the CNV. When TN stimulation was delivered before (P=0.62), or after (P=0.23) imagined movement onset there was no significant effect. Nor was a significant effect found when electrical stimulation of the TN was applied independent of imagined movement (P=0.45). Therefore, the excitability of the cortical projection to a muscle can be inhibited when electrical stimulation of the nerve supplying the antagonist muscle is precisely paired with the onset of imagined movement.
Somatosensory Evoked Potentials Show Plastic Changes Following a Novel Motor Training Task With the Thumb
Andrew, D., Haavik, H., Dancey, E., Yielder, P., & Murphy, B. (2015)
Clinical Neurophysiology, 126(3), 575-580
Objective: Accumulating evidence indicates that plastic changes can be maladaptive in nature, resulting in movement and neurological disorders.
The aim of this study was to further the understanding of these neurophysiological changes in sensorimotor integration (SMI) using somatosensory evoked potentials (SEPs) and concurrent performance changes following a repetitive typing task.
Methods: SEPs were recorded following median nerve stimulation at the wrist and performed pre and post intervention. 24 participants were randomly assigned to either an intervention group which performed a 20 min repetitive typing task or a control group which participated in a 20 min period of mental recitation.
Results: The P22–N24 amplitude increased by 59.6%, compared to only 0.96% increase following the control. The P22–N30 SEP peak amplitude increased on average 13.4% following the motor training, compared to only 0.92% following the control. Significant improvement in reaction time when comparing performance of the motor task for the intervention group was observed.
Conclusions: The N24 increase supports the involvement of cerebellar connections and the N30 increase provides further support for changes in SMI following motor learning.
Significance: Combining motor training tasks with electrophysiological techniques gives insight into the mechanisms of disordered SMI and whether the changes are adaptive or maladaptive.
Changes in H-reflex and V-Waves Following Spinal Manipulation
Niazi, I. K., Türker, K. S., Flavel, S., Kinget, M., Duehr, J., & Haavik, H (2015)
Experimental Brain Research, 233(4), 1165-1173
This study investigates whether spinal manipulation leads to neural plastic changes involving cortical drive and the H-reflex pathway. Soleus evoked V-wave, H-reflex, and M-wave recruitment curves and maximum voluntary contraction (MVC) in surface electromyography (SEMG) signals of the plantar flexors were recorded from ten subjects before and after manipulation or control intervention. Dependent measures were compared with 2-way ANOVA and Tukey’s HSD as post hoc test, p was set at 0.05. Spinal manipulation resulted in increased MVC (measured with SEMG) by 59.5 ± 103.4 % (p = 0.03) and force by 16.05 ± 6.16 4 % (p = 0.0002), increased V/M max ratio by 44.97 ± 36.02 % (p = 0.006), and reduced H-reflex threshold (p = 0.018). Following the control intervention, there was a decrease in MVC (measured with SEMG) by 13.31 ± 7.27 % (p = 0.001) and force by 11.35 ± 9.99 % (p = 0.030), decreased V/M max ratio (23.45 ± 17.65 %; p = 0.03) and a decrease in the median frequency of the power spectrum (p = 0.04) of the SEMG during MVC. The H-reflex pathway is involved in the neural plastic changes that occur following spinal manipulation. The improvements in MVC following spinal manipulation are likely attributed to increased descending drive and/or modulation in afferents. Spinal manipulation appears to prevent fatigue developed during maximal contractions. Spinal manipulation appears to alter the net excitability of the low-threshold motor units, increase cortical drive, and prevent fatigue.
A novel protocol to investigate motor training-induced plasticity and sensorimotor integration in the cerebellum and motor cortex
Baarbé, J., Yielder, P., Daligadu, J., Behbahani, H., Haavik, H., & Murphy, B. (2014)
Journal of neurophysiology, 111(4), 715-721.
Our group set out to develop a sensitive technique, capable of detecting output changes from the posterior fossa following a motor acquisition task. Transcranial magnetic stimulation (TMS) was applied over the right cerebellar cortex 5 ms in advance of test stimuli over the left cerebral motor cortex (M1), suppressing test motor-evoked potentials (MEPs) recorded in a distal hand muscle. Ten participants typed the letters Z, D, F, and P in randomized 8-letter sequences for ∼15 min, and 10 participants took part in the control condition. Cerebellar-M1 recruitment curves were established before and after the motor acquisition task. Cerebellar inhibition at 50% (CBI50) was defined as the intensity of cerebellar-M1 stimulations that produced MEPs that were 50% of the initial test MEP. Collection also occurred at stimulator intensities 5 and 10% above CBI50. A significant interaction effect of group (experimental and control) vs. time (pre- and postintervention) was observed [F(1,18) = 4.617, P = 0.046]. Post hoc tests showed a significant effect for the learning task in the experimental group [F(1,9) = 10.28, P = 0.01]. Further analysis showed specific disinhibition at CBI50 (P = 0.04), CBI50+5% (P = 0.008), and CBI50+10% (P = 0.01) for the experimental group only. Reaction time (P < 0.001) and accuracy (P = 0.006) improved significantly following practice, implying that disinhibition coincides with motor learning. No changes, however, were seen in the control condition. We conclude that this protocol is a sensitive technique that may be used to study cerebellar disinhibition with motor acquisition in vivo.
Selective changes in cerebellar-cortical processing following motor training
Haavik, H., & Murphy, B. A. (2013)
Experimental brain research, 231(4), 397-403.
The aim of this study was to investigate the effect of varying stimulation rate and the effects of a repetitive typing task on the amplitude of somatosensory evoked potential (SEP) peaks thought to relate to cerebellar processing. SEPs (2,000 sweep averages) were recorded following median nerve stimulation at the wrist at frequencies of 2.47, 4.98, and 9.90 Hz from 12 subjects before and after a 20-min repetitive typing task.
Typing and error rate were recorded 2-min pre- and post-typing task. Effect of stimulation rate was analysed with ANOVA followed by pairwise comparisons (paired t tests). Typing effects were analysed by performing two-tailed paired t tests. Increasing stimulation frequency significantly decreased the N30 SEP peak amplitude (p < 0.02). Both the 4.98 and 9.90 Hz rates lead to significantly smaller N30 peak amplitudes compared to the 2.47 Hz (p ≤ 0.01). The N24 amplitude significantly increased following the typing task for both 4.98 and 2.47 Hz (p ≤ 0.025). In contrast, there was a highly significant decrease (p < 0.001) in the N18 peak amplitude post-typing at all frequencies. Typing rate increased (p < 0.001) and error rate decreased (p < 0.05) following the typing task.
The results suggest that the N24 SEP peak amplitude is best recorded at 4.98 Hz since the N30 amplitude decreases and no longer contaminates the N24 peak, making the N24 visible and easier to measure, while still enabling changes due to repetitive activity to be measured. The decrease in N18 amplitude along with an increase in N24 amplitude with no change in N20 amplitude may be explained by the intervention reducing inhibition at the level of the cuneate nucleus and/or interior olives leading to alterations in cerebellar-cortical processing.
Keywords: Cerebellum, Cortical plasticity, Repetitive movement, Somatosensory evoked potentials, Human
Chiropractic Care in New Zealand: Theories, Practice and Research
Holt KR, Haavik H. (2012)
New Zealand Journal of Natural Medicine, Issue 6 Aug-Nov.
The role of spinal manipulation in addressing disordered sensorimotor integration and altered motor control
Haavik, H., & Murphy, B. (2012)
Journal of Electromyography and Kinesiology, 22(5), 768-776.
This review provides an overview of some of the growing body of research on the effects of spinal manipulation on sensory processing, motor output, functional performance and sensorimotor integration. It describes a body of work using somatosensory evoked potentials (SEPs), transcranial magnetic nerve stimulation, and electromyographic techniques to demonstrate neurophysiological changes following spinal manipulation. This work contributes to the understanding of how an initial episode(s) of back or neck pain may lead to ongoing changes in input from the spine which over time lead to altered sensorimotor integration of input from the spine and limbs.
The effects of manual therapy on balance and falls: a systematic review
Holt, K. R., Haavik, H., & Elley, C. R. (2012)
Journal of manipulative and physiological therapeutics, 35(3), 227-234.
Objective: The purpose of this study was to review the scientific literature on the effects of manual therapy interventions on falls and balance.
Methods: This systematic review included randomized and quasi-randomized controlled trials that investigated the effects of manual therapy interventions on falls or balance. Outcomes of interest were rate of falls, number of fallers reported, and measures of postural stability. Data sources included searches through June 2011 of Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, MEDLINE, EMBASE, CINAHL, PsycINFO, Allied and Complimentary Medicine, Current Controlled Trials, Manual Alternative and Natural Therapy Index System, Index to the Chiropractic Literature, National Institutes of Health (USA), and Google Scholar.
Results: Eleven trials were identified that met the inclusion criteria. Most trials had poor to fair methodological quality. All included trials reported outcomes of functional balance tests or tests that used a computerized balance platform. Nine of the 11 trials reported some statistically significant improvements relating to balance after an intervention that included a manual therapy component. The ability to draw conclusions from a number of the studies was limited by poor methodological quality or very low participant numbers. A meta-analysis was not performed due to heterogeneity of interventions and outcomes. Only 2 small trials included falls as an outcome measure, but as a feasibility study and a pilot study, no meaningful conclusions could be drawn about the effects of the intervention on falls.
Conclusion: A limited amount of research has been published that supports a role for manual therapy in improving postural stability and balance. More well-designed controlled trials with sufficient participant numbers are required to draw meaningful clinical conclusions about the role that manual therapies may play in preventing falls or improving postural stability and balance.
Key Indexing Terms: Accidental Falls; Postural Balance; Manual Therapy; Systematic Review; Chiropractic.
Subclinical neck pain and the effects of cervical manipulation on elbow joint position sense
Haavik, H., & Murphy, B. (2011)
Journal of manipulative and physiological therapeutics, 34(2), 88-97.
Objective: The objectives of this study were to investigate whether elbow joint position sense (JPS) accuracy differs between participants with a history of subclinical neck pain (SCNP) and those with no neck complaints and to determine whether adjusting dysfunctional cervical segments in the SCNP group improves their JPS accuracy.
Method: Twenty-five SCNP participants and 18 control participants took part in this pre-post experimental study. Elbow JPS was measured using an electrogoniometer (MLTS700, ADInstruments, New Zealand). Participants reproduced a previously presented angle of the elbow joint with their neck in 4 positions: neutral, flexion, rotation, and combined flexion/rotation. The experimental intervention was high-velocity, low-amplitude cervical adjustments, and the control intervention was a 5-minute rest period. Group JPS data were compared, and it was assessed pre and post interventions using 3 parameters: absolute, constant, and variable errors.
Results: At baseline, the control group was significantly better at reproducing the elbow target angle. The SCNP group’s absolute error significantly improved after the cervical adjustments when the participants’ heads were in the neutral and left-rotation positions. They displayed a significant overall decrease in variable error after the cervical adjustments. The control group participants’ JPS accuracy was worse after the control intervention, with a significant overall effect in absolute and variable errors. No other significant effects were detected.
Conclusion: These results suggest that asymptomatic people with a history of SCNP have reduced elbow JPS accuracy compared to those with no history of any neck complaints. Furthermore, the results suggest that adjusting dysfunctional cervical segments in people with SCNP can improve their upper limb JPS accuracy.
Key Indexing Terms: Proprioception; Upper Extremity; Manipulation, Spinal; Central Nervous System; Posture; Chiropractic
Fall risk profile and quality-of-life status of older chiropractic patients
Holt, K. R., Noone, P. L., Short, K., Elley, C. R., & Haavik, H. (2011)
Journal of manipulative and physiological therapeutics, 34(2), 78-87.
Objectives: The primary aim of this study was to estimate the prevalence of fall risk factors in older chiropractic patients. The secondary aim was to investigate the quality-of-life status of older chiropractic patients and to see whether a history of falling was related to quality-of-life status. Methods: A cross-sectional study was conducted at 12 chiropractic practices throughout Auckland, New Zealand, and Melbourne, Australia. The study involved gaining a profile of health status, fall history, and fall risk from active chiropractic patients who were 65 years or older.
Results: One hundred ten older chiropractic patients were approached, and 101 agreed to participate in this study (response rate, 91.8%). Thirty-five percent of participants had experienced at least 1 fall in the previous 12 months. Of those that had fallen, 80% had at least a minor injury, with 37% of fallers requiring medical attention and 6% suffering a serious injury. The prevalence of most fall risk factors was consistent with published data for community dwelling older adults. Quality of life of older chiropractic patients appeared to be good, but fallers reported a lower physical component summary score compared with no fallers (P = .04).
Conclusions: A portion of the older chiropractic patients sampled in this study had a substantial risk of falling. This risk could be assessed on a regular basis for the presence of modifiable fall risk factors, and appropriate advice, given when fall risks are identified
Key Indexing Terms: Chiropractic; Accidental Falls; Aged; Risk Factors; Postural Balance; Quality of Life
Transient modulation of intracortical inhibition following spinal manipulation
Haavik Taylor H, Murphy B. (2007)
Chiropractic Journal of Australia, Vol. 37, No. 3, Sep 2007: 106-116
Objective: To study the immediate sensorimotor neurophysiological effects of cervical spine manipulation using transcranial magnetic stimulation (TMS).
Design: Experimental design.
Setting: This study was carried out at the Human Neurophysiology Laboratory at the University of Auckland in Auckland, New Zealand.
Participants: Thirteen (13) subjects with a history of recurring neck stiffness and/or neck pain, but no acute symptoms at the time of the study were invited to participate in the study.
Intervention: Three (3) interventions were carried out in a randomised order: a control with no intervention, a passive head movement control condition, and a session of spinal manipulation of dysfunctional cervical joints.
Main Outcome Measures: Motor evoked potentials (MEP) and cortical silent periods (CSP) in the abductor pollicis brevis (APB) muscle of the dominant hand following transcranial magnetic stimulation (TMS) over the motor cortex.
Results: The major finding of this study was that the TMS-induced CSP measured in APB was significantly decreased for the first 20 minutes following spinal manipulation. No such changes were observed following either control condition, i.e. following no intervention or following passive head movement.
Conclusion: Spinal manipulation of dysfunctional cervical joints can lead to transient central neural plastic changes, as demonstrated by shortening of the TMS-induced CSP. This study suggests that cervical spine manipulation may alter sensorimotor integration. These findings may help to elucidate the mechanisms responsible for the effective relief of pain and restoration of functional ability documented following spinal manipulation treatment.
Cervical spine manipulation alters sensorimotor integration: a somatosensory evoked potential study
Haavik-Taylor, H., & Murphy, B. (2007)
Clinical neurophysiology, 118(2), 391-402.
Objective: To study the immediate sensorimotor neurophysiological effects of cervical spine manipulation using somatosensory evoked potentials (SEPs).
Methods: Twelve subjects with a history of reoccurring neck stiffness and/or neck pain, but no acute symptoms at the time of the study were invited to participate in the study. An additional twelve subjects participated in a passive head movement control experiment. Spinal (N11, N13) brainstem (P14) and cortical (N20, N30) SEPs to median nerve stimulation were recorded before and for 30 min after a single session of cervical spine manipulation, or passive head movement.
Results: There was a significant decrease in the amplitude of parietal N20 and frontal N30 SEP components following the single session of cervical spine manipulation compared to pre-manipulation baseline values. These changes lasted on average 20 min following the manipulation intervention. No changes were observed in the passive head movement control condition.
Conclusions: Spinal manipulation of dysfunctional cervical joints can lead to transient cortical plastic changes, as demonstrated by attenuation of cortical somatosensory evoked responses.
Significance: This study suggests that cervical spine manipulation may alter cortical somatosensory processing and sensorimotor integration. These findings may help to elucidate the mechanisms responsible for the effective relief of pain and restoration of functional ability documented following spinal manipulation treatment.
Keywords: Cervical spine manipulation; Human; Somatosensory evoked potentials; Brain plasticity; Somatosensory system; Sensorimotor integration
Research Poster Award at the The Parker Experience Seminars, Las Vegas, USA.
Scott Haldeman research award for the best paper presented at the WFC 2015 Congress, Athens, Greece.
Research Poster Award at the World Federation of Chiropractic’s 12th Biennial Congress in Durban, South Africa.
Research Poster Award at the World Federation of Chiropractic’s 11th Biennial Congress in Rio de Janeiro, Brazil.
Award winning paper at the Association of Chiropractic Colleges Research Agenda Conference, Las Vegas, USA.
First, second and third prize award winning papers at the Chiropractors’ Association of Australia Scientific Symposium, Melbourne, Australia, 22nd November.
Two award winning papers at the Association of Chiropractic Colleges Research Agenda Conference, Las Vegas, USA.
Research Poster Award at the World Federation of Chiropractic’s 10th Biennial Congress in Montreal, Canada.
First Prize Award winning paper Basic Science Category at the Association of Chiropractic Colleges Research Agenda Conference, Washington DC, USA.
Award in recognition of outstanding contribution to the chiropractic literature during 2007, awarded by the Editorial Board of the Chiropractic Journal of Australia.
New Zealand College of Chiropractic Alumni Association Chiropractor of the Year
New Zealand Chiropractor’s Association Chiropractor of the Year
Original Research Award (3rd Prize). World Federation of Chiropractic’s 9th Biennial Congress in Vilamoura, Portugal.
University of Auckland Doctoral Scholarship.
Top Achievers Doctoral Scholarship from the New Zealand Tertiary Education Commission.
Foundation for Chiropractic Education and Research Fellowship.
Department of Sport & Exercise Science-University of Auckland Summer Research scholarship.