<p>Binge drinking (drinking 5 units over a 2 hour period, followed by a period of abstinence) and high alcohol intake (more than 5 units a day), can lead to dependence, tolerance and cravings, which lead to a continuation of alcohol abuse to prevent withdrawal symptoms.</p>
<p>Chronic alcohol abuse can have adverse effects such as loss of balance and gait, slurred speech, slower reactions, poor memory consolidation, compromised emotional modulation and judgement. These effects in turn can lead to difficulties in social and emotional interactions, and a reduction in motivation, attention and impulse control.</p>
<p>These effects are studied and proven using methods such as MRI scans which show loss of neurons, particularly in the frontal lobe, the area most associated with reasoning, decision-making and rationality, however it can affect other areas of the brain such as the cerebellum (associated with balance and movement), hippocampus (memory) and amygdala (memory, decision making and emotional responses). [<ahref='#ref-1'>1</a>]</p>
<pclass='text-center'>Every year millions of people suffer from Alcohol use disorder, leading to physical and mental health problems. Prevalence of alcohol abuse and direct death caused by alcohol dependance across the world [<ahref='#ref-2'>2</a>]</p>
<p>Cerebellum (latin for "little brain") is one of the important areas of the brain with a primary function of motor control, which includes all directed movement, stability and balance, posture, gait and even reflexes. [<ahref='#ref-3'>3</a>] Cerebellum is also important for cognition, emotion, attention, language control and more. [<ahref='#ref-4'>4</a>] Antomatically, the cerebellum is located at the bottom of the brain, separate from the hemispheres. [<ahref='#ref-5'>5</a>] You can see the cerebellum highlighted in the model below.</p>
<p>Our understanding of Cerebellum's function with regards to its primary function, namely motor control, is that it does not initiate movement, but rather calibrates and coordinates the movement for precision and accurate timing, this can in turn affect stability while standing or walking, general posture and coordination. [<ahref='#ref-6'>6</a>]</p>
<p>Alcohol consumption has a detrimental effect on the motor functions of the cerebellum, in particular postural control and coordination. Damage to the cerebellum can also cause speech control problems and poor muscle coordination. For example, it is very common for patrol officers to check the driver’s ability to perform counting or walking exercises. This is why it is extremely dangerous to drive under the influence of alcohol since it could severely affect your visual and motor skills. </p>
<p>Brain imaging technology like computed tomography and magnetic resonance imaging (MRI) showed that heavy alcohol abuse is correlated to brain tissue shrinkage (significant loss of nerve cells) that could increase the risk of having a stroke. Moreover, long-term alcohol abuse can damage nerve signals that can result in permanent functional deficits in cognitive reasoning and mental balance. [<ahref='#ref-7'>7</a>] For instance, chronic alcoholics might no longer recover their ability to perform smooth and rapid movements as a result of motor control deficits. Abstinence from alcohol may show significant signs of improvement although it depends on how reversible their brain tissue injury is.</p>
<p>Past research shows how alcoholics perform poorly in visual and cognitive tasks that involve organizing information in the right temporal order. Lack of coordination between visual and motor skills could increase the danger of head injuries and accidental falls. Cerebellar degeneration can provoke severe adaptation issues to changes in visuospatial perception that makes them unable to walk straight or in the dark with their eyes closed. It can also have a significant impact in the cognitive control of self-movement and sense of position.</p>
<p>It is still unclear whether instability arising from alcohol abuse is directly caused from cerebellum dysfunction or from deficiency of the peripheral nervous system in body position and motor balance. Hence, more research is still needed to understand whether the cerebellar damage represents the prime cause of certain functional deficits in alcoholics. “New research must be conducted to determine if alcohol-related imbalance results from cerebellar pathology or from poor functioning of the peripheral nervous system in the body’s extremities, such as the hands and feet. Peripheral neuropathy can occur in alcoholics, resulting in decreased sensation that may lead to imbalance ” [<ahref='#ref-7'>7</a>]. Knowledge of this kind would be crucial for quickening recovery processes.</p>
<h2id='how-cerebellum-damage-affects-you'>How does damage and dysfunction of Cerebellum affect you?</h2>
<p>Damage to the cerebellum can cause a broad spectrum of motor and cognitive disturbances. It causes impairments in motor coordination and balance which lead to symptoms of clumsiness, irregular walking and feelings of dizziness. [1] Smooth and purposeful movements become difficult for subjects with cerebellar damage. [3]</p>
<p>Signs and symptoms can include a wide-based, uncoordinated walk; a back and forth tremor in the trunk of the body; uncoordinated movements of the arms and legs; slow and slurred speech and uncontrolled eye movements. This lack of coordination of motor movements is often referred to as Ataxia. [4] Subjects with left cerebellar damage report attention deficits while right cerebellar damage can lead to disrupted language skills. [1] </p>
<p>Since the cerebellum plays a role in cognition and emotion, cerebellar dysfunction also contributes to non-motor conditions such as certain neurodevelopmental disorders e.g. autism spectrum disorders. [3] Cerebellar abnormalities have been found in patients with ADHD, which is characterized by inattention, hyperactivity and impulsivity. Moreover neuroimaging studies show cerebellar differences in subjects with dyslexia. Dyslexic subjects have also shown a poorer performance on a variety of cerebellar motor tasks, which leads to the proposal that cerebellar dysfunction is a core neurobiological underpinning of dyslexia. It was found that early cerebellar damage leads to poorer outcomes than cerebellar damage in adulthood, which suggests that the cerebellum is important during development. [2]</p>
<p>Cerebellar damage caused by alcoholism specifically is one of the most common acquired forms of cerebellar ataxia. [5] The developing cerebellum is very sensitive to the toxic effects of alcohol. Children with fetal alcohol spectrum disorder, a group of conditions occurring when the mother consumed alcohol during pregnancy show many symptoms of cerebellar dysfunction. [6]</p>
<p>Since damage to the cerebellum impairs the ability to control motor movements clinical signs can be detected that occur throughout the body. In an examination of a patient the gait, posture and speech of the patient would be observed. [1] Patients with damage to the cerebellum may have abnormal posture and a broad-based gait. When scanning the speech an enunciation of individual syllables may occur. Nystagmus, abnormal eye movements can be detected by asking the patient to follow the movement of the examiner's finger. [2]</p>
<p>In the ‘Finger to nose & finger to finger test’ the patient is first asked to fully extend the arm and then touch their nose and secondly asked to touch the examiner's finger and then their nose. The difficulty of this test can be increased by adding resistance to the patient's movements. Checking for rapid alternating movements is another way of detecting cerebellum damage. In this task the patient is asked to place one hand over the next and have them flip one hand back and forth as fast as possible. Patients with cerebellar damage show abnormalities in this task. The ‘Rebound phenomenon’ (of Stewart & Holmes) is a test where the patient pulls on the examiner’s hand until they slip the hand out of their grasp. Normally the muscles would contract and stop their arm from moving further. Patients with cerebellar damage are unable to quickly stop their arm from moving in the desired direction.
Hypotonia is a condition that can be observed when checking the knee reflex. When the leg keeps swinging after the knee reflex is tested for more than 4 times this suggests damage to the cerebellum. [2]</p>
<h4>Assessment through Neuroimaging</h4>
<p>Magnetic resonance imaging is another way of detecting cerebellar damage. Alcoholic cerebellar degeneration is a cause for cerebellar atrophy which is a reduction of cerebellar volume and connections. [3] This cerebellar volume loss can be detected with neuroimaging techniques and can occur even in the absence of clinical signals such as ataxia. Cerebellar shrinkage occurs mostly for older alcoholics with at least a 10-year duration of alcoholism. [4]</p>
<liid='ref-1'>Crichton, R., & Ward, R. (2013). Metal-based neurodegeneration: from molecular mechanisms to therapeutic strategies. John Wiley & Sons. <ahref="https://doi.org/10.1002/9781118553480.ch12">https://doi.org/10.1002/9781118553480.ch12</a></li>
<liid='ref-2'>Global Burden of Disease Collaborative Network. Global Burden of Disease Study 2019 (GBD 2019) Results. Seattle, United States: Institute for Health Metrics and Evaluation (IHME), 2020. Available from <ahref="http://ghdx.healthdata.org/gbd-results-tool">http://ghdx.healthdata.org/gbd-results-tool</a></li>
<liid='ref-3'>Holmes, G. (1939). The cerebellum of man. Brain, 62(1), 1-30. <ahref="https://doi.org/10.1093/brain/62.1.1">https://doi.org/10.1093/brain/62.1.1</a></li>
<liid='ref-4'>Schmahmann, J. D. (2019). The cerebellum and cognition. Neuroscience letters, 688, 62-75. <ahref="https://doi.org/10.1016/j.neulet.2018.07.005">https://doi.org/10.1016/j.neulet.2018.07.005</a></li>
<liid='ref-5'>Purves, D., Augustine, G. J., Fitzpatrick, D., Hall, W. C., LaMantia, A. S., & White, L. E. (2011). Neuroscience, 5th edn. Sunderland, MA. pp. 417–423.</li>
<liid='ref-6'>Ghez, C. (1985). Fahn S. The cerebellum. Principles of neural science, 2nd edition. pp. 502–522</li>
<liid='ref-7'>Sullivan, E. V., Rosenbloom, M. J., Deshmukh, A., Desmond, J. E., & Pfefferbaum, A. (1995). Alcohol and the Cerebellum: Effects on Balance, Motor Coordination, and Cognition. Alcohol health and research world, 19(2), 138–141.</li>
